Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
462 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
Give three sources of evidence for evolution on Earth |
Evidence for evolution can be found in the fossil record, in selective breeding of domesticated animals, and through homologous structures. |
|
|
|
What is evolution? |
The gradual change of heritable factors in a species over time. |
|
|
|
When species "diverge" what is happening? |
Species with a common ancestor become more and more different, diverging from a common ancestor. |
|
|
|
Evolution does not occur when:
|
1. There is a large population
2. There is random mating 3. There is no mutation 4. There is no natural selection 5. There is no gene flow |
|
|
|
Define polyploidy
|
Polyploidy is when an organism (usually plants because of their ability to self–pollinate) have more than one full set of chromosomes. This is usually due to an error in meiosis where the cell does not go under cytokinesis.
|
|
|
|
Define disruptive selection
|
Disruptive selection is when individuals are more fit when they have one of either extreme traits. Natural selection favours both extreme traits over the average
|
|
|
|
Define directional selection
|
Directional selection is when an individual that has the extreme form of a particular trait is more fit. Natural selection favours one extreme trait over other phenotypes
|
|
|
|
Define stabilizing selection
|
Stabilizing selection is when individuals with the average trait are more fit. Natural selection favours those with an average form of the trait.
|
|
|
|
What do the variables in the Hardy Weingburg equations represent?
|
q = the recessive allele/gene frequency
p = the dominant allele/gene frequency p + q = 1 p^2 = homozygous dominant genotype/phenotype/trait frequency q^2 = homozygous recessive genotype/phenotype/trait frequency 2pq = heterozygous genotype/phenotype/trait frequency p^2+2pq+q^2=1 |
|
|
|
What is an example of polyploidy?
|
An example is the onion (A. cepa), 16 Chromosomes. The English Leek (A. cepa) has 32 chromosomes. Because the leek can no longer breed with the onion, speciation is said to have occurred.
|
|
|
|
What is phyletic gradualism?
|
Phyletic gradualism, or just gradualism, is the continuous change at a constant rate of heritable traits over a long period of time.
|
|
|
|
How does gradualism arise?
|
Through the gradual accumulation of mutations/variations over time.
|
|
|
|
What gives evidence to gradualism?
|
Gradual change in the fossil record with intermediate forms between species.
|
|
|
|
Give an example of gradualism
|
The modern horse evolved slowly with a gradual change of size and structure of foot with changing habitat.
|
|
|
|
What is punctuated equilibrium?
|
Evolution proceeding rapidly, in short bursts, cushioned by long periods of stability (no little to no change)
|
|
|
|
What happens during periods of stability in punctuated equilibrium?
|
Organisms become well suited to the environment, natural selection acting to maintain characteristics.
|
|
|
|
Equilibrium is punctuated by:
|
rapid environmental change (e.g. volcanic eruption, meteor impact) which leads to directional selection.
|
|
|
|
What evidence is there for punctuated equilibrium?
|
Gaps in the fossil record and lack of intermediate forms for many species.
Strata in fossil record show the appearance of many new species after a mass extinction. |
|
|
|
Define adaptive radiation
|
Adaptive radiation is the rapid speciation of a single ancestral lineage into two or more similar but distinct species. This occurs when different populations of the same species are exposed to a variety of different environmental selection pressures. Each population must adapt to a different niche, therefore making morphological adaptions as well. This may be further enhanced by reproductive isolation.
|
|
|
|
What is a similarity between convergent and divergent evolution?
|
Both explain the presence of similar structures in different organisms.
|
|
|
|
Describe Convergent evolution
|
Different ancestor. Converge to produce analogous structures. Species appearance becomes more similar over time. Species are unrelated (genetically different). E.g. Wings in insects, birds and bats.
|
|
|
|
Describe Divergent evolution
|
Common ancestor. Diverge to produce homologous structures. Species appearance becomes more different over time. Species are closely related (share genetic homology). E.g. Pentadactyl limb structure (vertebrates).
|
|
|
|
What are the four forms of reproductive isolation?
|
Temporal, Ecological, Behavioral, and Geographic
|
|
|
|
Define temporal reproductive isolation
|
When organisms cannot mate because of different mating seasons.
|
|
|
|
Define ecological reproductive isolation
|
Although in the same area, the two species cannot mate because they live in different habitats.
|
|
|
|
Define behavioral reproductive isolation
|
When two species cannot mate because they do not exhibit the right mating rituals (song, dance, etc.) or produce the right pheromones for each other. Members of the species will only mate with and be attracted to those who exhibit the correct behaviors.
|
|
|
|
Define geographic reproductive isolation
|
What was once a continuous population is divided into two or more smaller population by geographical circumstance, preventing them from mating with each other. (e.g. rivers change course, continents drift, organisms migrate, unfavorable habitat between the two populations)
|
|
|
|
Define gene pool
|
The total collection of different alleles in an interbreeding population.
|
|
|
|
Define allele frequency
|
Allele frequency is the proportion of all copies of a gene that is made up of a particular gene variant (allele).
|
|
|
|
What is a gene?
|
A heritable factor that consists of a length of DNA that controls or influences a specific characteristic.
|
|
|
|
Where are genes found?
|
Genes are found on a particular position on a chromsome (called a locus or loci)
|
|
|
|
What is an allele?
|
Alleles are the various forms of a gene (or alternate forms). They differ from each other by one or only a few nitrogenous bases.
|
|
|
|
Does the number of genes determine an organism's complexity?
|
No. An organism's complexity should also be determined by its organ systems, complexity of nervous system, and stimulus in response.
e.g. Humans have 22 333 genes while grapes have 30 434 genes. |
|
|
|
How do new alleles arise?
|
By mutations.
|
|
|
|
What is a mutation?
|
Random, rare changes in genetic material. They are permanent changes in the nitrogen base sequences of DNA.
|
|
|
|
Are mutations good or bad for an organism?
|
Mutations can be positive (increases fitness), negative (decreases fitness or leads to mortality), or neutral/silent (no effect).
|
|
|
|
What is a base substitution mutation?
|
A mutation resulting in the change of a single nitrogenous base.
|
|
|
|
What could be a possible effect of a base substitution mutation?
|
Changing one base could mean that a different amino acid is placed on the polypeptide chain. This could have a major influence, no influence, or tiny influence on the physical characteristics of the organism or protein function. E.g. Sickle cell anemia
|
|
|
|
What are the causes of sickle cell anemia? What are the affects of the disease?
|
Base substitution mutations. By changing the sixth codon triplet GAG to GTG, valine is produced instead of glutamic acid. The haemoglobin becomes sickle.
The biggest effect is interrupted is that sickle cells block blood flow and carry less oxygen. |
|
|
|
How is sickle cell anemia an example of natural selection.
|
Those with sickle cell anemia are immune to malaria, so in countries where malaria is a large cause of death, the debilitating disease can actually give individuals an advantage in their environment. Over time, sickle cell anemia becomes more prominent because they passed on their genes. Natural selection favored them.
|
|
|
|
Define genome
|
The genome is the whole of the genetic information (genetic material) of an organism. Think of it like a library. This includes genes and non–coding sequences.
|
|
|
|
What is the Human Genome Project?
|
The Human Genome Project was a mission whose primary goals were to discover the complete set of human genes and make them accessible for biological study. AKA, to determine the complete sequence of DNA bases in the human genome.
|
|
|
|
Did the Human Genome Project succeed?
|
Yes, but they now have the goal of discovering the function of all genes as well.
|
|
|
|
Draw a prokaryotic cell
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/63/64/63/14636463_m.png
|
|
|
|
How is prokaryotic DNA unique in comparison to eukaryotic DNA?
|
–Single chromosome
–Plasmids –One copy of each gene –Copies are made before binary fission (asexual reproduction) |
|
|
|
What is unique about plasmids?
|
–No histones
–small circular rings of DNA –not responsible for normal life processes –used for survival characteristics –can be passed between prokaryotes –can be incorporated into the nucleoid chromsome –Can be used to transfer genes into bacteria |
|
|
|
What are the characteristics of eukaryotic DNA?
|
–linear DNA held in helix
–associated with histones –two copies of each gene (one maternal, one paternal) –DNA strands are supercoiled into chromosomes when not being transcribed |
|
|
|
Chromosomes vary by:
(4 things) |
–Length
–position of centromere –banding pattern –what genes are on it (in the same species the same gene is always located at the same loci) |
|
|
|
What are homologous chromosomes?
|
Homologous chromosomes carry the same sequence of genes but not the necessarily the same alleles of those genes. One is from mom, one is from dad.2n ––> full chromosome set.
|
|
|
|
What is a diploid nucleus?
|
Diploid nucleus has two of each chromosome (2n). All human genes (except for the gametes) are diploid, and they have 46 chromosomes.
|
|
|
|
What is a haploid nucleus?
|
Haploid nucleus has one of each chromosome (n). Only gametes are haploid. Human haploid cells have 23 chromosomes.
|
|
|
|
Define sister chromatids
|
When chromosomes replicate up prior to cell division, the two identical chromosomes are said to be sister chromatids until they split at the centromere at the start of anaphase.
|
|
|
|
What is a characteristic feature of a member of a species?
|
A characteristic feature is the chromosome number. All members of a species have the same number of chromosomes, and only organisms with the same amount can interbreed. To a degree, n number (chromosome number) reflects the complexity of the organism.
|
|
|
|
How do chromosome numbers change?
|
It is possible for chromosomes to fuse or split during evolution, but chromosome numbers tend to stay the same for millions of years.
|
|
|
|
What is the difference between a karyotype and a karyogram?
|
Karyotype: the humber and type of chromosomes in a nucleus, not a photo or diagram of them.
Karyogram: a diagram/photo of chromosomes present in a nucleus of a eukaryote cell arranged in homologous pairs of decreasing length. |
|
|
|
How are chromosomes arranged in a karyogram?
|
By size, shape, centromere location, and banding pattern.
|
|
|
|
How is sex determined?
|
Everyone has two sex chromosomes, but women always have XX and men always have XY. The presence and expression of the SRY gene on the Y chromosome leads to male development.
|
|
|
|
What is the difference between autosomal chromosomes and sex chromosomes.
|
22 pairs of autosomes, which are in homologous pairs.
1 pair of sex chromosomes, which are either XX or XY. There are many genes in the non–homologous region which are not present in Y. |
|
|
|
What was John Cairns known for?
|
Producing images of DNA molecules from E. coli. He was able to measure the length of the molecule through autoradiography.
|
|
|
|
What is genome size?
|
The total number of DNA base pairs in one copy of a haploid genome. (for humans it is 3.2 billion base pairs).
|
|
|
|
How can one identify Down Syndrome and sex from a karyogram?
|
Through a karyogram, if there are three 21 chromosomes (trisomy 21), the human has down syndrome. If there are two X chromosomes, the human is female, and if it has an X and a Y it is male.
|
|
|
|
What are some differences between mitosis and meiosis? (give 3)
|
–mitosis vs meiosis
–one division vs two divisions –diploid cells produced vs haploid gametes produced –no crossing over vs crossing over in prophase I –No chiasmata vs chiasmata form –homolous pairs do not associate vs homologous pairs associate as bivalents –diploid to diploid vs diploid to haploid |
|
|
|
Define meiosis
|
Meiosis is a reduction division of the nucleus to form haploid gametes.
|
|
|
|
What are three reasons why there is near infinite variation in genetic information of gametes?
|
Random orientation and crossing–over, as well as sexual reproduction, a fusion of two gametes.
|
|
|
|
What is independent assortment?
|
The idea that the separation of alleles for one gene will occur independently of the separation of alleles for another gene. This does not apply to linked genes.
|
|
|
|
How is random orientation related to independent assortment?
|
Random orientation something that happens during metaphase I in prophase. Homologous pairs line up randomly on the equator, and then are separated from each other during anaphase I. This promotes independent assortment.
|
|
|
|
Why is meiosis important in sexual reproduction.
|
To preserve the number of chromosomes, a reduction division must go under way. As gametes fuse in sexual reproduction, there must n chromosomes to form 2n in the zygote.
|
|
|
|
What occurs during Interphase I of meiosis?
|
–DNA replication
–chromosome duplicates attached by a centromere form sister chromatids –preparation for meiosis |
|
|
|
What occurs during Prophase I of meiosis?
|
–synapsis causes homologous pairs to form a bivalent
–nuclear membrane dissolves –centrioles migrate to the poles of the cell –crossing–over between non–sister chromatids may occur. |
|
|
|
What is crossing over? What are chiasmata?
|
Crossing over is the exchange of genetic material between homologous chromatids. Chiasmata form between non–sister chromatids, which is the point around which the exchange of alleles may occur.
|
|
|
|
Is crossing over sure to happen?
|
No. Crossing over might, and often does, happen, but it does not always happen.
|
|
|
|
What are the three steps to crossing over?
|
1. Synapsis. Homologous chromosomes associate.
2. Chiasmata formation. 3. Recombination. Segments of DNA twist around, swapping segments of DNA. |
|
|
|
What is the standard notation for writing genotypes of linked genes?
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/77/46/14647746_m.png
|
|
|
|
What are the key points when drawing chiasmata?
|
•
|
Use colour of shading toindicate the each of the sister chromatids
• |
|
|
What occurs during metaphase I of meiosis?
|
–Random orientation
–bivalents line up on the equator –spindle fibres attach to the centromeres of the sister chromatids. |
|
|
|
Difference between random orientation and independent assortment?
|
Random orientation: Behaviour of homologous pairs or pairs of sister chromatids in meiosis.
Independent assortment: behavour of alleles of unlinked genes as a result of meiosis. |
|
|
|
What occurs in anaphase I of meiosis?
|
–bivalent is split and half the chromosomes move towards each pole.
–spindle fibres contract or shorten. –reduction division |
|
|
|
What occurs in telophase I of meiosis?
|
–cytokinesis begins to occur
–new nuclei form –chromosomes decondence |
|
|
|
What is non–disjunction? How many gametes does it affect?
|
Non–disjunction is a cell's failure to perform meiosis correctly. Homologous chromosomes fail to separate correctly at anaphase. If it occurs during Anaphase I, it affects all gametes. If it occurs during anaphase II it affects half of the gametes.
|
|
|
|
What is the effect of non–disjunction? Give an example.
|
Trisomy (one chromosome too many), or monosomy (one chromosome too few. E.g. Trisomy 21 (AKA Down Syndrome) is when an individual has three of chromosome 21.
|
|
|
|
What is amniocentisis?
|
Amniocentesis is type of prenatal testing given to pregnant women to determine the karyotype of the child they are carrying. A sample of amniotic fluid is taken with a syringe. The fluid contains cells from the foetus, which is used for karyotyping.
|
|
|
|
What is Chorionic Villus Sampling?
|
A type of prenatal testing. A biopsy needle takes a few cells from the chorion (a membrane in the placenta), which are then cultured. When enough cells have grown, they are used for karyotyping.
|
|
|
|
What are the risks of prenatal testing?
|
There is a chance that a miscarriage might occur.
|
|
|
|
What occurs in prophase II of meiosis?
|
–nuclear membrane dissolves
–no crossing–over –centrioles move to opposite poles –chromosomes consisting of two sister chromatids. |
|
|
|
What occurs in metaphase II of meiosis?
|
–pairs of sister chromatids align at the equator
–random orientation –spindle fibres attach to centromeres. |
|
|
|
What occurs in anaphase II of meiosis?
|
–Spindle fibres contract and shorten.
–The centromeres split –the chromatids become chromosomes and are pulled to opposing poles. |
|
|
|
What occurs in telophase II of meiosis?
|
–nuclear membrane reforms
–chromosomes decondense –new haploid nuclei are formed –cytokinesis begins –four haploid gamete cells created |
|
|
|
Which phase of meiosis is this?
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/95/31/14649531_m.jpg
|
Anaphase II
|
|
|
Which phase of meiosis is this?
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/95/43/14649543_m.jpg
|
Metaphase II
|
|
|
Which plants did Mendel work with?
|
Pea plants
|
|
|
|
What are Mendel's laws? (3)
|
1. Law of dominance
2. Law of segregation 3. Law of independent assortment |
|
|
|
Explain the law of dominance.
|
If there is an organism with alternate forms of a gene, it will express the form that is dominant.
|
|
|
|
Explain the law of segregation.
|
When gametes fuse, each have one allele for every gene. A diploid cell therefore has two alleles for each trait.
|
|
|
|
Explain the law of independent assortment.
|
Each pair of alleles separates independently from other pairs of genes (as long as they are not on the same chromosome).
|
|
|
|
Define genotype and phenotype.
|
Genotype: reprentation of alleles through letters (AA, Aa, aa, Bb)
Phenotype: Characteristic/trait of an organism (blood type, hair colour, earwax type) |
|
|
|
Define dominant and recessive alleles.
|
Dominant allele: allele that is expressed.
Recessive allele: allele that is only expressed when in the homozygous state. |
|
|
|
Define codominant alleles.
|
Both alleles have an affect on phenotype when in heterozygote.
|
|
|
|
What is a test cross procedure?
|
A procedure used to find out the genotype of an organism by breeding it with an organism of known genotype. (Can be illustrated with a punett square)
|
|
|
|
What is a monohybrid cross?
|
A genetic cross which involves one trait and one pair of contrasting genes.
|
|
|
|
Cross between a heterozygous smoothseed and a wrinkled seed pea plant.(Smooth is dominant over wrinkled)
|
Answer in booklet |
|
|
|
What is the notation for co–dominant punnet square?
|
Capital C with superscript capital letters representing allele
|
|
|
|
Roan coat color seen in some shorthorncattle which is a mixture of red hairs and white hairs. Each individual hair is either all red or allwhite, but both appear together.Cross a roan shorthorn bull with awhite shorthorn cow. Include P1, F1, GR and PR. Determine the probability of getting a redoffspring?
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/98/43/14649843_m.png
|
|
|
|
What is the notation for incomplete dominance (heterozygote is a blend of allele phenotype. E.g. red and white make pink)
|
Capital letter with ' to signify different allele. E.g. red = RR
white = R'R' Pink = RR' |
|
|
|
What is an example of multiple alleles?
|
Blood types (The term multipleallele is used to describe a genethat has three or more alleles, and each allele can produce a distinct phenotype)
|
|
|
|
What is the notation for blood types?
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/98/55/14649855_m.png
|
|
|
|
What is sex–linkage?
|
Genes that are found on the sex chromosomes.
|
|
|
|
3 examples of sex–linked disorders
|
Colour blindness
Haemophilia Muscular dystrophy |
|
|
|
Notation for sex–linked genes?
|
sex linked alleles are designated byadding a superscript tothe letter X ONLY.A letter if the gene is known or a question mark if it is unknown.
|
|
|
|
Are calico male cats possible? Why or why not?
|
Not possible because it is a case of sex–linked co–dominance. Two X chromosomes are therefore required to make it happen. The only way a male can be calico is if it has three sex chromosomes, two X and one Y.
|
|
|
|
Are genetic diseases common?
|
No, especially since many genetic diseases are autosomal recessive. The chances of both parents carrying a mutant gene are slim.
|
|
|
|
Cystic fibrosis is a __________ ___________ disorder.
|
recessive autosomal
|
|
|
|
Huntington's disease is a __________ ___________ disorder
|
dominant autosomal
|
|
|
|
What are the rules of pedigrees?
|
–Males are squares, females are circles
–Males always on the left of marriages –Generations represented by roman numerals on the left hand side –Children are below parents and are listed and numbered in chronological order of birth –a genotype is listed below each circle or square –shaded circle/square shows an exhibited phenotype. –half shaded or dotted circles are carriers |
|
|
|
Awoman and man who both have normal vision have two children. Their oldest son has normal vision, but theiryoungest son is colorblind. The youngestson marries a normal vision woman and they have two color–blind daughters. Red–greencolor–blindness is a recessive sex–linked disorder.
|
note that generation one genotypes should be below and men should be on the left.
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/99/03/14649903_m.png
|
|
|
How do you analyse a pedigree? Autosomal vs. Sex linked
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/99/12/14649912_m.png
|
|
|
|
How do you analyse a pedigree? Dominant vs. Recessive
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/99/18/14649918_m.png
|
|
|
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/64/99/21/14649921_m.png
|
1. autosomal dominant
2. sex linked dominant 3. sex–linked recessive 4. recessive autosomal |
|
|
|
What is a dihybrid cross
|
Unlike a monohybrid cross, a dihybrid cross determines the allele combinations of offspring for two particular genes that are unlinked.
|
|
|
|
How do you find the gametes of the parents in a dihybrid cross?
|
Using the FOIL method. E.g. For parent AaBb, gametes would be:
|
|
|
|
When crossing two heterozygous parents in a dihybrid cross, what will be the genotypic and phenotypic ratio patterns?
|
GR pattern: 1 : 2 : 2 : 1 : 4 : 1 : 2 : 2 : 1
PR pattern: 9 : 3 : 3 : 1 |
|
|
|
How do you do a dihybrid cross?
|
The same as a monohybrid cross, except you have to find the gametes of the parents, and the punnet square may be up to 16 squares.
|
|
|
|
Define linked genes.
|
Linked genes are genes which do not assort independently of one another because their gene loci are on the same chromosome. The only way they can be separated is through recombination (via crossing over).
|
|
|
|
Define linkage group.
|
A group of linked genes that are often inherited together because of their location on the same chromosome (e.g. red hair, pale skin, and freckles).
|
|
|
|
For an individual with linked genes AABB and aabb, the gametes before recombinants are AB and ab. If recombination occured, what would the recombinants be?
|
aB and Ab
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/65/53/45/14655345_m.png
|
|
|
How can you identify linked genes?
|
–Through a dihybrid cross, if most of the offspring resemble the parent's phenotypes, it is likely because the genes are linked.
– Heterozygous testcross of unlinked genes = 1 : 1 : 1 : 1 phenotypic ratio –Heterozygous testcross of linked genes = 1 : 1 : 0.1 : 0.1 phenotypic ration (uncommonphenotypes are recombinants) |
|
|
|
What is polygenic inheritance?
|
The inheritance of a single phenotypic trait that is controlled by two or more pairs of genes.
|
|
|
|
Polygenic inheritance gives rise to _________ __________ in the phenotype.
|
continuous variation
|
|
|
|
What are two examples of polygenic inheritance?
|
Human skin colour, wheat kernal colour
|
|
|
|
How does polygenic inheritance give rise to continuous variation?
|
Multiple genes give a small, equal influence over the phenotype. In affect, the blend together, giving a gradation effect in phenotype.
|
|
|
|
What is epistasis?
|
Epistatic genes are genes that suppress the effect of a gene at another locus (in polygenic inheritance).
e.g. The gene for albinism is epistatic because even though someone might have the gene for pigmentation, the albino gene does not allow pigment expression to occur. The epistatic gene can be dominant or recessive. |
|
|
|
Coat color in dogs. Gene 1 controls coat colour. Blackcoat color (B) is dominant to brown (b)Gene 2 controls pigment expression.This is an epistatic gene that prevents pigment formation and color formation (W) in the dominant form to thegene that does not prevent pigment formation and color formation (w) in the recessiveform.Cross a white dog (heterozygous for nopigment, and heterozygous for black colour) and a black dog (heterozygous forblack colour expression.)
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/65/60/83/14656083_m.png
|
|
|
|
What is discontinuous variation?
|
Individuals fall into descrete classes or categories that cannot be measured across a range. E.g. blood groups. There is no in between option. You either are in a blood group or you aren't.
|
|
|
|
What is continuous variation?
|
Individuals fall into a complete range of measurements from one extreme to the other. E.g. Height has a complete range of phenotypes, from very short to very tall and everywhere in between.
|
|
|
|
How else might polygenic traits be influenced other than genetics?
|
Environment. E.g. Dietary factors and childhood diseases can effect height. Exposure to sun, burns, and scarring can effect skin colour.
|
|
|
|
In brief, why do women tend to have lighter skin tones than men living in the same population?
|
Lighter skin allows for greater intake of vitamin D from the sun, which is necessary for embryo development. The more vitamin D a mother intakes, the healthier a newborn is likely to be as vitamin D is necessary for calcium absorption.
|
|
|
|
What methods are involved in the analysis of DNA and gene transfer?
|
–copying DNA in a lab –– the polymerase chain reaction (PCR)
–Using DNA to reveal its owner's identity –– DNA profiling –Mapping DNA by finding where every A,T, C, and G –– gene sequencing, including the Human Genome Project –Cutting and pasting genes to make new organisms –– gene transfer –Clone cells and animals |
|
|
|
At a crime scene, a small amount of blood is found, carrying a small amount of the criminal's DNA. What method might a forensic investigator use so that more DNA can be used for the investigation?
|
PCR (polymerase chain reaction) may be used. It amplifies small samples of DNA through the use of a machine called a thermocylcler.
|
|
|
|
What are the three steps to PCR?
|
1. Denaturation: DNA is heated to separate two strands
2. Annealing: DNA primers attach to opposite ends of the target sequence 3. Elongation: A heat–tolerant DNA polymerase (Taq) copies the strand |
|
|
|
Multiple suspects have been identified for a crime. How method might forsenic investigators use to identify the culprit?
|
DNA profiling using gel electrophoresis.
|
|
|
|
Most human's genes are almost exactly alike. Then how can biologists determine between individuals using gel electrophoresis?
|
Satellite DNA, sections of DNA separating coding genes, are made up of short tandem repeats and vary in length between different individuals. These fragments are what is used for DNA profiling.
|
|
|
|
How does electrophoresis separate DNA fragments?
|
DNA is put into wells in porous agarose gel.
The gel is exposed to an electric current. Because DNA is negatively charged, it will go towards the positive end. Heavy, long fragments of DNA stay close to the wells because they cannot move easily through the gel. Light, short fragments travel farther because they move easily through the porous gel. |
|
|
|
How is DNA profiling used for paternity testing?
|
DNA samples from the mother, child, and potential father are used. If the child matches with half of dad's bands and half of mom's band's, it is a match.
|
|
|
|
What is a standard lane in gel electrophoresis?
|
A standard lane is the "control" lane. It has a band at every possible spot.
|
|
|
|
Another word for gene transfer is_____________.
|
transgenics
|
|
|
|
Why is transgenics possible?
|
The genetic code is universal (with a few rare exceptions).
|
|
|
|
What is a basic technique used for gene transfer involving plasmids, a host cell, restriction enzymes, and DNA ligase.
|
Foreign DNA has the gene of interest cut with restriction enzymes, making a sticky end pattern (along with plasmid).
PCR DNA ligase is used to ligate the gene of interest and plasmid. Creates recombinant DNA. Insert into bacterium. Bacteria will clone itself and recombinant DNA DNA purification. E.g. The cloning of genetically engineered bacteria to create human insulin. |
|
|
|
What is the difference between transfection and transformation?
|
Transfection is when recombinant plasmid is inserted into the host cell (for eukaryotic cells) and transformation is when recombinant plasmid is inserted into the desired host cell (for prokaryotic cells)
|
|
|
|
What are some uses for transgenic crops?
|
1. Engineering crops to extend shelf life of fresh produce (Flavr Savr tomatoes).
2. Engineering crops to provide protection from insects (Bt corn made to be toxic to corn borers) 3. Other (Salt tolerant tomato plants, golden rice made with beta–carotene. |
|
|
|
What are some uses for transgenic animals?
|
1. Engineering animals to enhance production (Sheep made to produce more wool (cysteine))
2. Engineering animals to produce desired products (sheep engineered to produce alpha–1–antitrypsin to help those with emphysema) 3. Other (goat milk containing spider silk. human insulin produced by bacteria) |
|
|
|
What are the potential benefits to transgenic crops?
|
–Allows new characteristic into the gene pool
–Increased productivity of food. –Less use of pesticides, reducing cost of farming –Can grow in new regions, decreasing deforestation. |
|
|
|
What are the potential harms to transgenic crops?
|
–Could have surprise harmful effects on humans.
–Accidental mixing with native plants may result in competition. –Possibility of cross pollination into weeds, making super weeds –Reduces genetic variation/biodiversity (killing corn borers) |
|
|
|
What is a clone?
|
A clone is a group of genetically identical organisms, derived from a single original parent cell.
|
|
|
|
Are there natural methods of cloning?
|
Yes. Many plant species and some animal species clone themselves. E.g. Runners are clones produced by asexual reproduction by many plants, allowing fast propagation.
|
|
|
|
Which animals clone themselves?
|
Star fish, Plenaria, Mammals (twins)
|
|
|
|
How can animal cells be cloned at an early embryonic stage?
|
Micropipetting is used to extract stem cells and grow them elsewhere, making identical twins.
|
|
|
|
How can adult animals be cloned?
|
Through Somatic Cell Nuclear Transfer (SCNT).
|
|
|
|
What are the steps of Somatic Cell Nuclear Transfer?
|
–A surrogate mother is treated with hormones to increase egg production (such as FSH)
–An egg cell is enucleated, removing the surrogate mother's genetic information. –The egg cell is fused with the nucleus of a body cell of another animal (the one to be cloned), making the egg cell diploid. –An electric shock stimulates mitosis. –After a blastocyst has formed, it is implanted into the surrogate mother's uterine lining. |
|
|
|
What is an example of an animal clone?
|
Dolly the Sheep.
|
|
|
|
Is human cloning possible?
|
Yes, but it is illegal.
|
|
|
|
What is the difference between reproductive cloning and therapeutic cloning?
|
Reproductive cloning is done for the goal of making a living clone of an organism.
Therapeutic cloning is done for the goal of cloning an organism's tissues and using them for therapeutic uses (stem cells). |
|
|
|
What are the arguments for therapeutic cloning?
|
–May be used to cure serious diseases.
–Stem cell research may result in future discoveries and beneficial technologies. –Stem cells can be harvested from embryos which would have died anyway. –Cells are taken at a stage when the embryo's nervous system feels no pain. |
|
|
|
What are the arguments against therapeutic cloning?
|
–Involves the creation and destruction of human embryos.
–Embryonic stem cells could become cancerous cells if they continue to divide. –More embryos are generally produced than needed, killing many excess embryos. –Different technology could be developed to fulfill similar roles. |
|
|
|
Define species |
A group of organisms that can interbreed to produce fertile offspring. (on a test, be specific) |
|
|
|
What are four defining characteristics of a species? |
1. They have similar physiological and morphological characteristics that can be observed and measured. 2. They have the ability to interbreed to produce fertile offspring. 3. They are genetically distinct from other species. 4. They have a common phylogeny (family tree). |
|
|
|
What happens when members of different species mating and producing offspring? |
Hybrids are created. Examples are ligers, mules, zorses |
|
|
|
Are hybrids fertile? |
No. If one generation of hybrids are produced, a second generation is very unlikely to occur. |
|
|
|
What might happen if populations are isolated from each other (reproductively isolated)? |
The two groups will evolve along different pathways due to different selective pressures. |
|
|
|
What is speciation? |
When groups within a species evolve to the point that the two groups cannot interbreed successfully, this is called speciation. A new species has formed. |
|
|
|
What is an autotroph? |
An organism capable of making their own organic materials as a food source from simple inorganic substances. |
|
|
|
What are some expamples of autotrophs? |
Cyanobacteria, algae, grass, trees, flowers |
|
|
|
What is a heterotroph? |
An organism that cannot make their own food from inorganic materials and must obtain organic molecules from other organisms. |
|
|
|
What are some examples of heterotrophs? |
zooplankton, fish, birds, insects, humans |
|
|
|
What is a consumer? |
A consumer is any organism that cannot synthesize their own food from inorganic material and relies on others for food. They ingest (eat) other organisms (organic matter) that are living or have recently been killed. |
|
|
|
What is decomposer? |
A decomposer is any organism that eats non-living organic matter. Breaks down the body parts of dead organisms. |
|
|
|
What is the difference between a detritivore and a saprotroph? |
Detritivores ingest dead organic mater. Saprotrophs live in dead organic matter, secrete digestive enzymes, and absorb the products of digestion. |
|
|
|
What is a detritivore? Why are they important? Give examples. |
An organism that ingests non-living organic matter like dead leaves, faeces, or carcasses. They are important in the recycling of nutrients within the food chain. Examples are earthworms, woodlice, dung beetles, bottom feeders, hyenas, vultures. |
|
|
|
What is a saprotroph? Why are they important? Give examples. |
An organism that lives on or in dead organic matter and secretes digestive enzymes, absorbing the digestive products. They are important in the recycling of nutrients within the food chain and breaking down waste material. Examples are fungi and bacteria. |
|
|
|
Define community. Give examples. |
A community is a group of populations living and interacting with each other in an area. E.g. soil community in a forest, or fish community in a river |
|
|
|
Define ecosystem. Give examples. |
An ecosystem is a community and its abiotic environment. This is similar to a habitat but it refers to where a group of interacting populations lives rather than where a single species lives. Examples are forests, ponds, and oceans. |
|
|
|
What does abiotic mean? |
non-living components of the environment (water, air, soil, minerals) |
|
|
|
What does biotic mean? |
living components of the environment (plants, animals, decomposers, microorganisms) |
|
|
|
What is a systemic sampling technique? |
A technique of random sampling using a quadrat or systemic sampling using a transect. |
|
|
|
What is a transect? |
(in systemic sampling) A line traced from one environment to another (like a grassland to a woodland) the line may be 10-50m long and can be made using a rope or tape measure. |
|
|
|
What is a quadrat? |
(in systemic sampling) A square device which is placed down every meter along a transect or at other specific intervals in order to count the organisms found within the quadrat. |
|
|
|
Why is systemic sampling useful? |
It is useful for the study between distribution of organisms living along the transect. It answers questions like: Are populations heavy in one area? Why? What resource changes might make this happen? |
|
|
|
How is the supply of inorganic nutrients maintained? |
Through nutrient cycling. Ecosystems recycle carbon, nitrogen, phosphorus, and other elements and compounds necessary for life to exist (and water for the water cycle). |
|
|
|
Why are decomposers important in ecosystems? |
They break down organic molecules into inorganic molecules so they can be used again (nutrient cycling) They prevent waste from building up. They play a major role in the formation of soil. A rich black layer called humus is made up of organic debris and nutrients released from decomposers. |
|
|
|
What cycle allows ecosystems to have the potential of being sustainable over a long period of time? |
Nutrient cycling |
|
|
|
How does the cycle of nutrients go? |
-Producers convert CO2 to C6H12O6 -Consumers eat producers -consumers die and are broken down by decomposers -Their minerals are returned to the soil -Producers absorb nutrients from the soil and grow new sources of food -the cycle is complete |
|
|
|
Why is sunlight important in an ecosystem? |
Sunlight is the main source of energy for all life either directly or indirectly |
|
|
|
What is the role of photosynthesis? |
To convert light energy into chemical energy: sunlight+CO2+H2O --> C6H12O6+ATP (chemical energy) |
|
|
|
What is a food chain? How does it connect to energy flow? |
A food chain is a sequence showing feeding relationships and energy flow between species. The direction of the arrows show which way the energy flows. |
|
|
|
Energy flows in ______ way. |
one |
|
|
|
What are three examples of food chains (at least three linkages) using these organisms: fox, snake, seeds, insects, grass, hawk, bird, toad, mice, spider |
grass—>insect—>spider—>toad seed—>bird—>snake—>hawk seed-->mouse-->snake-->hawk-->fox |
|
|
|
Energy flows in one way. Where does the flow start, and where does it end? Which types of organisms are in the middle? |
Energy from sunlight --> producers --> primary consumers --> secondary consumer --> tertiary consumer |
|
|
|
What is a way in which nutrients are gained (from already abiotic element), and how nutrients are lost. |
-Gained by the weathering of rocks -Lost by leaching/sedimentation (eg. Shells sinking to sea bed |
|
|
|
The supply of nutrients is ______. |
Finite |
|
|
|
After energy from carbon compounds has been used, what happens to it? |
ATP is used for cellular respiration. It is used for body functioning and is then converted into heat. |
|
|
|
Can heat energy be used again once it has left an organism? |
No. Heat generated through cellular respiration is lost to the environment. It cannot be used as a biological energy source again. |
|
|
|
Where does heat go after it is "lost"? |
It radiates into the surrounding environment and cannot be used again. |
|
|
|
Can energy be recycled like nutrients? |
No. But this is not usually a problem because the sun is constantly providing new energy to producers. |
|
|
|
How efficient are energy transformations? (How much heat is lost between organisms) |
Only 10-20% of energy can be used from the last trophic level to the next. Approximately 80-90% of energy is lost at each trophic level. |
|
|
|
The energy supply from the sun is ________ and ___________. |
continuous/variable |
|
|
|
Why is energy lost between trophic levels? |
-Not all organisms can be ingested (some parts are rejected) -Not all food can be assimilated into the body. It is excreted or coughed up. -Some organisms die without being eaten by the next trophic level. -Most energy is lost as heat because of cellular respiration. |
|
|
|
What is an energy pyramid? |
A diagram that shows how much energy flows through each trophic level in a community. |
|
|
|
What is the correct unit for measuring in an energy pyramid? |
kJ m-2 y-1 (-2 and -1 are superscripts) |
|
|
|
Why is an energy pyramid shaped as a triangle? |
Because the most energy is at the bottom and the higher in the trophic levels you get, the less energy there is (because energy is lost between trophic levels) |
|
|
|
Draw a diagram of an energy pyramid where sunlight produces 10 000 kJm-2y-1. |
energy pyramid |
|
|
|
What is a food web? |
An interconnecting series of food chains. (since each organism eats more than one type of food, a food chain does not tell the whole story) |
|
|
|
What is a trophic level? What is its purpose? |
A trophic level refers to the organism's position on a food chain. It offers a way to classify organisms by their feeding relationships with the other organisms in the same ecosystem. |
|
|
|
What determines the length of a food chain? What is the average length of a food chain? |
Average length: four trophic levels Determinants: How much energy enters the ecosystem, number of organisms in the chain, and how much light is available. |
|
|
|
What is the biomass of a trophic level? |
An estimate of a trophic level's mass of all organisms within that level. Less biomass at higher trophic levels occurs because not all energy or biomass from previous levels is passed on. |
|
|
|
Plants (mainly cotton Sedges) eaten by caribou, voles, lemmings, ground squirrels, jaegers, grizzly bears (primary consumers) caribou are eaten by wolves, jaegers (secondary consumers) voles and lemmings are eaten by wolves, wolverines, jaegers, gulls weasels, owls, hawks (tertiary consumers) ground squirrels are eaten by wolves, wolverines, weasels, owls, hawks, and grizzly bears Draw a food web. What is the trophic level of the weasels? |
arctic food web secondary |
|
|
|
How is carbon equilibrium maintained? |
Through the removal and return of CO2. Through sink and fluxs of CO2 |
|
|
|
How is CO2 removed from the atmosphere? |
Photosynthesis |
|
|
|
*How is CO2 moved through the biosphere? |
Cell respiration Feeding Death Incomplete decomposition and fossilization combustion |
|
|
|
*What is a sink in carbon? What is a flux? |
A sink is carbon being trapped somewhere int he biosphere. A flux is carbon moving throughout the biosphere. |
|
|
|
What are four examples of carbon sinks? |
Carbon compounds in fossil fuels Carbon compounds in producers Carbon compounds in consumers Carbon compounds in dead organic matter |
|
|
|
*What are seven examples of carbon fluxs? |
Cell respiration Photosynthesis Incomplete decomposition and fossilization Feeding Egestion Combustion Death |
|
|
|
Draw a carbon cycle |
|
|
|
|
Why is carbon called organic? |
It is a crucial element to living things and is part of the definition of a living thing |
|
|
|
What do chemotrophs do? |
They fix carbon by utilizing energy bonds of inorganic compounds such as hydrogen sulifide |
|
|
|
In aquatic ecosystems, what form does carbon exist as? |
dissoloved carbon dioxide or hydrogen carbonate ions H2O + CO2 —>H2CO3 —> H+ + HCO3-
Carbonicacid—> hydrogen ion and bicarbonate ion< |
|
|
|
Where does carbon dioxide in the hydrosphere/atmosphere go? |
It diffuses from the hydrosphere/atmosphere and is absorbed by photosynthetic autotrophs |
|
|
|
How is carbon dioxide produced? |
Cellular respiration |
|
|
|
What produces methane gas? |
Methanogens |
|
|
|
What are methanogens? Where do their products accumulate? |
Methanogenic archaeans are anaerobic microbes that produce methane gas when they metabolize food. This gas can accumulate in the atmosphere or ground. |
|
|
|
Where are methanogens commonly found? |
Wetlands (they produce marsh gas), and in the digestive tract of mammals and termites. |
|
|
|
How long is methane averaged to persist in the atmosphere? |
8.4 years |
|
|
|
How does the burning of fossil fuels (methane gas) produce carbon dioxide? |
Methane (AKA natural gas) can be oxidized into making carbon dioxide and water in the atmosphere. CH4 +2O2 --> 2H2O + CO2 |
|
|
|
What is peat? |
Partially decomposed organic matter. It is brown waterlogged soil found in certain types of wetlands (mires and bogs). |
|
|
|
How does peat form? |
Peat forms by the partial decomposition of plant material due to acidic and or anaerobic conditions in wetlands that are do not allow decomposers to live. |
|
|
|
How can peat be used as a fossil fuel? |
Peat is energy rich and once cut and dried, it can burn easily as a fossil fuel. |
|
|
|
Is peat a renewable resource? |
No. Once it is used it is gone and takes thousands of years to reform. |
|
|
|
How does coal, oil, and gas form? |
Partially decomposed organic matter left in the right conditions will be transformed into other types of fossil fuels. This occurs when sediments accumulate over peat and compress it for many geological eras. Heat and pressure cause chemical transformations in a hydrocarbon chain. This can change it into coal or into oil and gas that accumulate into porous rocks. |
|
|
|
Why is carbon important for some marine animals? |
Some marine organisms take dissolved carbon out of the water and use some of it to make their carbonate shells. |
|
|
|
What kind of animals use carbon in this way. |
Reef-building corals (coral polyps) and molluscs (such as snails, clams, oysters) develop hard parts that are composed of calcium carbonate. |
|
|
|
Ca2+ + 2HCO3-—> CaCO3 + CO2 + H2O What does this equation simulate? |
The use of carbon to make calcium carbonate shells. |
|
|
|
What happens to the shells of molluscs after they die? |
They accumulate at the bottom of the ocean. After being buried and compressed for many years they eventually turn to limestone rock. |
|
|
|
Carbon becoming trapped in limestone rock is a huge _______ ____. |
Carbon sink |
|
|
|
Is it possible to measure the size of carbon sinks and fluxes? |
No. Only estimates are available, measured in gigatonnes/year. |
|
|
|
What trend is generally seen carbon fluctuations annually? |
Because large amounts of forests and other plant-life do not photosynthesize in the northern-hemisphere winters, carbon dioxide levels raise in the winter and lower in the summer due to increased photosynthesis. |
|
|
|
What are the two most significant greenhouse gases? |
Carbon dioxide and water |
|
|
|
What are two other greenhouse gases that have less impact? |
Methane and nitrogen oxides |
|
|
|
How much do greenhouse gases take out of the entire atmosphere? |
Less than 1% |
|
|
|
What does the impact of greenhouse gases depend on? |
1. Its ability to absorb long wave radiation (especially infrared/heat) 2. Its concentration in the atmosphere |
|
|
|
Compare methane and CO2 |
CO2 vs Methane Very abundant in the atmosphere vs. Not very abundant lasts 50-200 years vs lasts 8-12 years one times the effect vs. 33 times the effect of CO2 |
|
|
|
What kind of radiation is emitted from the warmed Earth? |
When sunlight (short wave radiation) touches an object, some of the light energy is absorbed and converted into heat energy or long wave radiation. |
|
|
|
What kind of radiation is absorbed by greenhouse gases? |
Longer wave radiation. This retains the heat in the atmosphere. |
|
|
|
Why is it called "the greenhouse effect"? |
The atmosphere's ability to retain heat is similar to the way a greenhouse does. Natural greenhouse gases are like the glass. They are more transparent to light than heat, so they let light leave, but trap heat inside. As a result, some heat that is radiated from the earth is trapped, keeping the atmosphere warm. |
|
|
|
How does the greenhouse effect work? |
1. Sunlight enters Earth's atmosphere. 2. Most sunlight reflects off Earth's surface, but some is absorbed and converted into longwave radiation. 3. Longwave radiation is absorbed by greenhouse gases and reradiated, warming the atmosphere. |
|
|
|
What is the precautionary principle? |
When a human-induced activity raises significant threat or harm to the environment or human health, then precautionary measures should be taken even if there is no scientific consensus regarding cause and effect. AKA, you must prove that it is not harmful to do it rather than do it because there is no proof that it is harmful. |
|
|
|
What changes might the global temperature have on arctic systems? |
Change in arctic conditions, rising sea levels, expansion of temperate species, decomposition of detritus trapped in ice, increased spread of pests, behavioural changes, loss of habitat, extinction and loss of biodiversity in food chains. |
|
|
|
What is binomial nomenclature? |
A naming system for species. One part of the name is the genus, which is the first capitalized word. The second part is the species, the lower case word. When written longhand it is underlined. When typed it is italicized. |
|
|
|
What is the mnemonic used for the taxa? (Name the taxa as well) |
Did King Phillip come over for great sex? Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (Domain is often left out) |
|
|
|
What are the three domains? |
Archaea, Bacteria, Eukaryote |
|
|
|
What are the kingdoms of Eukaryote?
|
Animalia, Fungi, Protista, Plantae |
|
|
|
What are the eight taxa that humans fall into? |
Eukaryote, Animalia, Chordata, Mammalia, Primates, Hominidae, Homo, sapiens |
|
|
|
What are the four phyla of plants? |
Bryophyta, Filicinophyta, Coniferophyta, Angiospermophyta |
|
|
|
What are the characteristics of bryophyta? Give examples |
No 'true' leaves or roots (non-vascular) Spores produced in a capsule at the end of a stalk Anchored by rhizoids Short in stature E.g. Mosses and liverworts |
|
|
|
What are the characteristics of filicinophyta |
Have leaves, roots, and non-woody stems (vascular) Spores in sporangia on underside of leaf Have large leaves (fronds) that are divided into leaflets Max hight 15 m E.g. Ferns |
|
|
|
What are the characteristics of coniferophyta? |
Have leaves, roots, and woody stems (vascular) Shrubs or trees with roots Seeds found in cones in females. Males produce pollen Leaves usually narrow with a thick waxy cuticle Can get quite tall in stature (max 100 m) E.g. Conifers and pines |
|
|
|
What are the characteristics of angiospermophyta? |
Have leaves, roots, and woody stems (woody or non-woody)(vascular) Many different charactertics Seeds found in fruits, flowers Have flowers E.g. Flowering plants and grasses |
|
|
|
What are the six phyla of animals (not the only six, but the six you are learning)? |
Porifera, Cnidaria, Platyhelminthes, Annelida, Mollusca, Arthropoda |
|
|
|
What are the characteristics of porifera? |
Asymetrical, no mouth or anus, pores through body, attached to a surface e.g sponges |
|
|
|
What are the characteristics of cnidaria? |
Radial, mouth but no anus, may have tentacles with stinging cells e.g. jellyfish and anenomes |
|
|
|
What is the outcome of increased concentrations of greenhouse gases? |
-higher global average temperature -more frequent, intense heat waves -some areas more prone to drought -some areas more prone to intense periods of rainfall, flooding -tropical storms more frequent, more powerful -changes in ocean currents -climate pattern changes -warming of arctic regions |
|
|
|
What is the relationship between increased greenhouse gases and the enhanced greenhouse effect? |
It is hypothesized that an increase in greenhouse gases intensifies the greenhouse effect because increased abundance results in overall increase in longwave radiation absorption. |
|
|
|
Are greenhouse gases bad? |
Not necessarily. In fact, without them our earth would not be able to retain the heat that it does. However, they are naturally present in small quantities, and rise in human populations increases the demand of fuel for food increase, so excess waste gasses are produced. |
|
|
|
What is the most likely cause of increased atmospheric levels of CO2? |
Human activity that includes the combustion of human activity. Evidence is the sharp increase of atmospheric carbon dioxide after the industrial revolution. |
|
|
|
What are some possible effects of increased carbon dioxide in water? |
Ocean acidification. Although CO2 is important for marine animals, too much makes the environment unsuitable for organisms such as corals, sea urchins, oysters, clams, and photosynthetic algae. |
|
|
|
What are some ways humans produce carbon dioxide? |
-transportation that is based on burning fossil fuels -deforestation -heating homes -purchasing goods -commuting -purchasing foreign goods |
|
|
|
What are some ways humans produce methane? |
Increased meat consumption leads to a large amount of methane escaping into the atmosphere. |
|
|
|
What are some ways humans produce oxides of nitrogen? |
burning fossil fuels, organic and commercial fertilizers, industrial processes (production of nitric acid) |
|
|
|
What might be a result of electric power production? |
-air pollution -sulphur dioxide emission from coal burning power plants leads to acid rain -acid rain acidifies freshwater and kills aquatic organisms |
|
|
|
Who are Charles Darwin and Alfred Wallace? |
Two men who believed in natural selection (the fathers of evolution) |
|
|
|
Define evolution. |
The cumulative change in the heritable characteristics of a population over many generations. |
|
|
|
What are three examples of evolution? |
1. Fossil record 2. Artificial breeding/selective breeding 3. Homologous/vestigial structures |
|
|
|
Discuss the embryological evidence for evolution |
Embryology, the study of embryos at their earliest stages, is evidence for evolution because many animals look similar in early embryonic development. Although these animals may not be closely related, evidence of a common ancestor can be seen in the embryos' similar developments due to common genes from a common ancestor. |
|
|
|
Discuss the biochemical evidence for evolution |
Biochemistry, the study of evolutionary relationships between organisms, is evidence of evolution. All living organisms use DNA as their genetic code. Differences and similarities between the genetic code can be used to compare the relationships between organisms. Amino acid sequences can be used to determine their closeness in relation. Few differences suggest recent speciation. |
|
|
|
How does the fossil record provide evolutionary evidence? |
-The sequence in which fossils appear in strata provide evidence of the sequence in which organisms evolved -The record gives us a history of life and allows us to trace decent -shows that there are many living organisms that don't have an identical form in the fossil record -shows a succession of fossil forms in sedementary rock from ancient forms to modern forms |
|
|
|
Discuss the fossil record |
-Fossils tend to be simpler than the organisms that exist today -sequences of fossils show gradual series' of changes. -continuous fossil record is often rare with gaps -One conclusion formed from fossils is that life is constantly changing and has been for millions of years. |
|
|
|
What is significant about Acanthostega? |
-It had four legs but gills and a fish like tail and lived in water. -It is the missing link -It is an example of a transitional fossil which shows the links between certain ancestral groups (fish and amphibians) -Supports the notion that life began in the ocean and moved onto land |
|
|
|
How does selective breeding show evidence of evolution? |
-Selective breeding is when humans breed animals and plants for certain traits -This changes their characteristics by artificial means. -Traits are more desirable for the human, but would not necessarily help offspring better survive in the wild -Evidence of natural selection |
|
|
|
How are animals selectively bred? |
A specific plant or animal is chosen for a desired trait and is bred with another with a similar trait. The resulting offspring have a higher potential of displaying that trait as well. This cycle is repeated until the trait is achieved at the desired rate. |
|
|
|
What are examples of selective breeding? |
-speed in racehorses -milk production in cows -trail scenting in dogs -crops bred for increased yeild -crops bred for increased disease resistance |
|
|
|
Define Homologous structures |
-Certain anatomy in different groups of animals or plants that are similar in structure and placement. -They may be used in different ways. Similar usage shows closer relation. -Is evidence of descendant of a common ancestor |
|
|
|
Define vestigial organs |
-Anatomical features that are fully developed in one group but reduced or non-functional in another -Structures may have been important for ancestors. -They are traces of ancestors' anatomy which are no longer essential -evidence of evolution |
|
|
|
Define adaptive radiation |
-Species in a group diverge rapidly and evolve into a number of similar but distinct species -Each new species occupies a new environment -Spreading into different environments is accompanied with adaptations -this may happen when there is a niche that no other species is taking and that group takes it |
|
|
|
Define common ancestry |
-An organism which is the shared ancestor of two or more different descendant groups of organisms -All living organisms on Earth are descended from a common ancestor or ancestral gene pool |
|
|
|
How do pentadactyl limbs act as evidence for evolution? |
-they are an example of homologous structures -an explanation for similar structures is common ancestry -limbs have adapted to different modes of locomotion -shows that all organisms (humans, bats, monkeys, dolphins) descended from a common ancestor |
|
|
|
How might homologous structures emerge as a result of adaptive radiation? |
When exposed to different environmental pressures, certain members exploited different niches. -this resulted in certain morphological changes, but the general structure was conserved |
|
|
|
What are two examples of adaptive radiation? |
-Different species of lemur in Madagascar with different specialities tp adapt to a new niche -Darwin's finches on the Galapagos Islands with a wide variety of beak shapes to adapt to different food sources |
|
|
|
How might speciation occur? |
-Two groups are geographically isolated so they develop in different groups -gene pools are separated, so through evolution different gene pools will evolve in each group |
|
|
|
What are the two steps to speciation? |
Geographical isolation (allopatric speciation): A barrier is created between gene pools so that the gene pools can no longer intermix. Reproductive isolation (sympatric speciation): Two varieties of a species live in the same geographical area but cannot interbreed. -speciation occurs when formally interbreeding groups of organisms are prevented from producing fertile offspring. |
|
|
|
Why is it sometimes difficult to classify and determine between populations? |
because populations are always gradually diverging, it is natural to see continuous variation across geographical ranges |
|
|
|
Explain the development of melanistic insects in polluted areas. |
-The peppered moth occurs in two variations, light and dark -Before the industrial revolution, light coloured moths were more common because they camouflaged better -after the industrial revolution, dark coloured moths became more common because the trees were covered in soot. -dark colouration increased survival, became more prevalent in the gene pool |
|
|
|
Define natural selection |
-A passive process (not purposeful decisions) -favorable traits are picked by the demand of the environment -an ongoing process which disrupts the genetic equilibrium -makes some members more likely to contribute to the gene pool -uneven reproduction, certain individuals with certain traits survive better and reproduce more successfully |
|
|
|
Why is variation and natural selection important in a population? |
-organisms vary within a species in many ways -variation connects to successfulness of a species -some variations cause individuals to be fit -some variations make them less fit -some individuals will be more suited and pass on to the next generation -better suited survive and reproduce more -this is natural selection |
|
|
|
What are the sources of variation in a species? |
1. mutations in DNA 2. Meiosis 3. Sexual reproduction |
|
|
|
How do mutations lead to variation? |
-they provide new alleles -the raw material for evolutionary change -mutations can be positive or negative or neutral on the survival of species -most effects are minor or neutral -mutations occur constantly by chance, causing change in the gene pool |
|
|
|
How does meiosis lead to variation? |
-4 cells are reproduced that are genetically different and only 50% of the parent genome -variation in gametes occurs because of: 1. random orientation 2. crossing over |
|
|
|
How does sexual reproduction promote variation? |
-Genes are mixed -random fertilization leads to new gene combinations |
|
|
|
Why are adaptations important? |
-adaptations are inherited -this enables them to become more fit -individuals that inherit well adapted genetic characteristics are more successful at reproducing and survival -less adapted tend to die earlier or have fewer offspring |
|
|
|
Why do organisms produce so many offspring? |
-Numerous offspring increases the chances for species survival -ensures that at least a few offspring will survive in an environment where many die -number of offspring produced is greater than the number that can survive |
|
|
|
Is having too many offspring a problem? |
-Overpopulation may occur -competition is created for food resources and living spaces because of this -a struggle for survival is created, in which some will live and some will die (survival of the fittest) |
|
|
|
What is meant by biological fitness? |
-Fitness describes how successful an organism has been at passing on its genes. -most likely, this is because individual survives longer to reproduce due to higher fitness |
|
|
|
Describe the rule of "survival of the fittest" |
-better adapted (on average) will reproduce more successfully -lead to a fit population -environmental changes cause most fit to reproduce most -species evolves a new adaptation -gene frequency changes -favourable alleles are passed on by those who reach reproductive age -better adapted alleles become more frequent -this is natural selection |
|
|
|
Why is important for an organism to survive and successfully mate? |
-survival offers opportunity to reproduce -reproduction ensures genes are passed on -species become extinct if organism stops reproducing |
|
|
|
How can natural selection effect a population over time? |
1. increased frequency of better adapted characteristics 2. decrease in the frequency of other characteristics 3. natural selection leads to changes in the species |
|
|
|
What three main features is natural selection based off of? |
-Variation allows some individuals to be better suited to their environment -Overpopulation leads to a struggle for survival -Passing on of successful traits to the next generation |
|
|
|
What kind of natural selection is likely in a stable environment? |
Long, slow evolution (hundreds of thousands of years) |
|
|
|
What kind of natural selection is likely in a rapidly changing environment? |
rapid, short term evolution (months, years, decades) |
|
|
|
Why is overpopulation important? |
-Overpopulation leads to -struggle for existence leads to -variation leads to -natural selection If there's never overpopulation, there isn't a struggle and everyone survives. Nothing changes |
|
|
|
How might a group of bacteria become resistant to antibiotics? |
-first dose kills most bacteria -a few are naturally resistant -resistant individuals survive and reproduce -no competition results in a good breeding ground -offspring contain large percentage of resistant bacteria -increasing numbers of resistant bacteria are produced -doctors may prescribe different antibiotics to control bacteria -this is why antibiotics should be used sparingly, because they can result in resistance |
|
|
|
What are some risks of antibiotic overuse? |
-new syphilis strains -new tb strains -no cure for those who get sick from super-resistant germs, so can only rely on immune systems -finding a new antibiotic is only a temporary solution -antibiotics cannot be found fast enough |
|
|
|
What are the characteristics of kingdom archaebacteria? |
-prokaryotic -unicellular -feed by autotrophy and heterotrophy |
|
|
|
What are the characteristics of kingdom eubacteria? |
-prokaryotic -unicellular -autotrophy and heterotrophy |
|
|
|
What are the characteristics of kingdom protista? |
-Eukaryotic -unicellular and multicellular -autotrophy and heterotrophy |
|
|
|
What are the characteristics of kingdom fungi? |
-Eukaryotic -Unicellular and multicelluar -Heterotrophy |
|
|
|
What are the characteristics of kingdom plantae? |
-Eukaryotic -multicellular -Mostly autotrophic, some heterotrophic |
|
|
|
What are the characteristics of kingdom animalia? |
-Eukaryotic -Multicellular -heterotrophy |
|
|
|
Why don't viruses fit into the five-kingdom system? |
-Not classified living organisms -they do not reproduce independently -do not contain similar structures as other organsims (organelles) -they do contain genetic material |
|
|
|
Why does natural classification help identify species? |
-Natural classification groups species that have common ancestry. -These groups share important attributes and homologous traits. -E.g. plant and fungi were classified together but it has been seen that they evolved separately so now they are classified differently |
|
|
|
What are the characteristics of platyhelminthes |
-bilateral symetry -flat bodies -unsegmented -mouth but no anus -e.g tapeworm, planaria, liverflukes, flatworms |
|
|
|
What are the characteristics of annelida? |
-bilateral symettry -bristles often present -segmented -mouth and anus -earthworms, leeches, sandworms -segmented worms |
|
|
|
What are the characteristics of mollusca? |
-muscular foot and mantle -shell may be present -segmentation not visible -mouth and anus -slugs, clams, squids, snails |
|
|
|
What are the characteristics of arthropoda? |
-bilateral symmetry -exoskeleton -segmented body -jointed appendages -spiders, scorpions, millipedes, insects |
|
|
|
How do you remember the animal phyla? |
Polly came promptly and made a commotion Porifera, cnidaria, platyhelminthes, annelida, mollusca, arthropoda, chrodata |
|
|
|
Identify six different characteristics for classifying organisms. |
-Morphology: The shape of animal structures -Anatomy: The type and number of structures -Cytology: The structure of cells and function -Phytochemistry: Organic compounds that are produced by -Chromosome number: Similar chromosome numbers likely indicate close relation -Molecular differences: Proteins (AAs) and DNA seqeunces differ one species and another |
|
|
|
Define cladistics |
A system of classification that groups taxa together according to the characteristics they have evolved most recently |
|
|
|
What is a clade? |
A group of organisms that have evolved from a common ancestor -clades can be small or large, and large clades can contain smaller clades |
|
|
|
Define cladogram |
-tree diagram that represents cladistics in a visual way. -shows the similarities and differences between species -show most probable sequence in divergence |
|
|
|
How do you read a clade? |
-cladograms are mostly based on DNA base sequences of the amino acid seqeunces in a protein -the branching points are called nodes -nodes denote speciation, a common ancestor splits into two or more species -length of lines represents estimated time since divergence |
|
|
|
What is the evidence used to show species are a part of a clade? |
-Biochemical evidence -mutations that persist and are inherited at a predictable rate |
|
|
|
Define phylogeny |
The study of the evolutionary past of species |
|
|
|
Is there a relationship between differences between species and the time since they diverged from the common ancestor? |
-There is a positive correlation -this is because sequence differences accumulate gradually -the rate of mutations can be used as a molecular clock to calculate time since divergence |
|
|
|
Compare analogous and homologous traits |
homologous vs analagous common ancestor vs different ancestor divergent evolution vs convergent evolution close relation vs little relation different function vs similar function pentadactyl limbs vs eyes |
|
|
|
What does cladistic reveal about similar structures and evolutionary origins? |
-that similar structure does not denote similar evolutionary origins -reclassifying a taxon is called circumscription -this is done in an effort to show monophyletic groups -thereby showing they all have a common ancestor |
|
|
|
Is DNA the only evidence for evolutionary relationship? |
No |
|
|
|
Compare divergent and convergent evolution |
divergent vs convergent moving away vs moving towards become dissimilar vs become similar common ancestor vs no common ancestor different environmental pressures cause divergence vs similar environmental pressures cause convergence adaptive radiation vs analagous structures |
|
|
|
How do nucleic acids differ from each other (3)
|
–Double ring or single ring
–Nitrogenous base (cytosine, guanine, adenine, thymine, uracil) –type of sugar (ribose or deoxyribose) |
|
|
|
What does NTP stand for?
|
Nucleoside triphosphate
|
|
|
|
What types of RNA are there?
|
mRNA
tRNA rRNA |
|
|
|
What does DNA stand for?
|
deoxyribonucleic acid
|
|
|
|
What does RNA stand for?
|
Ribonucleic Acid
|
|
|
|
What does ATP stand for?
|
Adenozine Triphosphate
|
|
|
|
What are the main components of a nucleotide?
|
1. 5 carbon sugar (pentose)
2. Phosphate group 3. Nitrogen base (adenine, cytosine, guanine, thymine, uracil) |
|
|
|
What's the difference between a purine and a pyrimidine?
|
A purine is a nitrogenous base made up of a double carbon–nitrogen ring.
A pyrimidine is a nitrogenous base made up of a single carbon–nitrogen ring. |
|
|
|
Which nitrogenous bases are purines, and which are pyrimidines?
|
Purines: Guanine and Adenine
Pyrimidine: Cytosine, Thymine, and Uracil |
|
|
|
What kind of bonds (and how many) form between the nitrogenous bases, connecting the two strands of DNA?
|
Hydrogen bonds form between the nitrogenous bases. Three form between Guanine and Cytosine. Two form between Adenine and Thymine (in DNA only. In RNA Uracil pairs with Adenine).
|
|
|
|
What is a nucleosome? What is its purpose?
|
A nucleosome is the complex of a DNA strand supercoiled around a histone protein core. Its purpose is to supercoil DNA so it fits inside the nucleus.
|
|
|
|
Which enzymes are responsible for DNA replication? (5)
|
1. Helicase
2. DNA Polymerase III 3. RNA Primase 4. DNA Polymerase I 5. Ligase |
|
|
|
Why is DNA replication necessary? What is the main reason? What are other reasons?
|
Main reason: cell division/mitosis
Other reasons: cell growth and repair, embryonic development |
|
|
|
In brief, what are the five steps to DNA replication?
|
1. Helicase unzips the double helix
2. RNA primase acts as a primer 3. DNA polymerase III adds new nucleotides to parent strand. 4. DNA polymerase I removes RNA primase and replaces it with DNA nucleotides. 5. Ligase enzygme joins Okazaki fragments to form a solid strand. |
|
|
|
What is the end result of DNA replication?
|
2 identical DNA strands, each strand holding one parent strand.
|
|
|
|
What is a polysome?
|
A polysome is a protein used to speed up the process of replication in eukaryotic cells. It creates many replication bubbles so the process goes in both directions quickly.
|
|
|
|
What is meant by replication being 'semi–conservative'?
|
DNA replication creates DNA that is half the original parent DNA strand and half a newly synthesized DNA strand. Half of the parent strand is conserved in the replicate.
|
|
|
|
Explain the first step to DNA replication. Hint: Helicase
|
Using Helicase, weak hydrogen bonds are broken/separated between the nitrogenous bases at the origin bubble/replication bubble to form a replication fork.
|
|
|
|
Explain the second step to DNA replication. Hint: RNA Primase
|
RNA primase acts as a primer and attaches to exposed DNA nitrogenous bases to which a new DNA nucleotide will pin onto the parent strand using DNA polymerase III.
|
|
|
|
Explain the third step to DNA replication. Hint: DNA polymerase III
|
DNA polymerase III Attaches onto the RNA primase to add new nucleotides to original parent strand on both leading/lagging strands.
DNA polymerase III attaches nucleoside triphospates, which release energy when two phosphate groups are released. This allows them to join to the parent strand and become nucleotides. |
|
|
|
Explain the fourth step to DNA replication. Hint: DNA polymerase I
|
DNA polymerase I removes RNA primase and replaces it with DNA nucleotides.
|
|
|
|
Explain the fifth and final step of DNA replication. Hint: Ligase
|
The ligase enzyme will join discontinuous fragments on lagging strand called Okazaki fragments to form a solid strand on lagging side.
|
|
|
|
Give a diagram of the first step of DNA replication. Hint: Helicase
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/87/78/37/14877837_m.jpeg
|
|
|
|
Draw a diagram of the second step of DNA replication. Hint: RNA primase
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/87/78/40/14877840_m.jpeg
|
|
|
|
Draw a diagram of the third step of DNA replication. Hint: DNA polymerase III
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/87/78/43/14877843_m.jpeg
|
|
|
|
Draw a diagram of the fourth step of DNA replication. Hint: DNA Polymerase I
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/87/78/46/14877846_m.jpeg
|
|
|
|
Draw the fifth and final step of DNA replication. Hint: ligase
|
//fce-study.netdna-ssl.com/2/images/upload-flashcards/87/78/49/14877849_m.jpeg
|
|
|
|
What are three differences between DNA and RNA?
|
–DNA vs RNA
–Double strand vs single strand –Uses Thymine vs Uses Uracil –Deoxyribose sugar vs Ribose sugar –Genetic instruction vs Carry out DNA instruction for protein synthesis –Large, billions of N Bases vs Small, thousands of N Bases –Location: Nucleus only vs Location: Nucleus, ribosome, or cytoplasm |
|
|
|
What are three similarities between DNA and RNA?
|
–Both nucleic acids
–Both genetic material in the nucleus –Both key components for protein synthesis |
|
|
|
What are the three types of RNA? (full names)
|
(messenger) mRNA, (transfer) tRNA, (ribosomal) rRNA
|
|
|
|
What is the purpose of mRNA? Where is it found? What is its shape?
|
Purpose: Copies the DNA code
Location: Nucleus and cytoplasm Shape: Linear |
|
|
|
What is the purpose of tRNA? Where is it found? What is its shape?
|
Purpose: Transport and assemble amino acids onto growing protein chain.
Location: Cytoplasm and ribsome Shape: clover leaf |
|
|
|
What is the purpose of rRNA? Where is it found? What is its shape?
|
Purpose: Oversee the process of protein synthesis
Location: Inside the ribosome Shape: Linear strand supercoiled like a ball of yarn to form the ribosome. |
|
|
|
What is the school analogy?
|
Principal — DNA
Secretary — mRNA Students — tRNA (does all theactual work)Teacher — rRNA (supervisor) |
|
|
|
What is the central dogma of genetics?
|
DNA ––> RNA ––> protein
|
|
|
|
What is the first step of transcription? Hint: RNA polymerase
|
RNA polymerase unwinds DNA at specific sites from promoter codon to terminator codon. This section contains instructions for one specific gene only, to make a specific protein.
|
|
|
|
What is the second step of transcription? Hint: Free RNA nucleotides
|
Free RNA nucleotides are assembled to the exposed DNA nucleotides on the antisense strand
|
|
|
|
What is the third step of transcription? Hint: phosphodiester bond
|
RNA nucleotides bond together with covalent (phosphodiester) bond to form mRNA.
|
|
|
|
What is the fourth step of transcription? Hint: Before it leaves the DNA it must...
|
mRNA detaches from the DNA strand and DNA winds back together unchanged.
|
|
|
|
What is the fifth step of transcription? Hint: Snurpius Splice...
|
mRNA is processed (only in eukaryotic cells). Introns are removed. Exons are spliced together.
|
|
|
|
What is an intron? What is an exon?
|
An intron is a section of the mRNA which was transcribed from satellite DNA. It is a non–coding region, which is therefore excised.
An exon is a section of the mRNA which was transcribed from coding DNA. It is a coding region, which is therefore spliced together and kept. |
|
|
|
What is the sixth step of transcription? Hint: pores
|
Mature mRNA leaves nucleus through nuclear pores.
|
|
|
|
If the DNA sense strand is AAC TCG GGC, what is the antisense strand, the mRNA strand, the tRNA anticodons, and the amino acids produced.
|
DNA sense strand: AAC TCG GGC
Antisense strand: TTG AGC CCG mRNA strand: AAC UCG GGC tRNA strand: UUG AGC CCG Amino acids: Asparagine, serine, proline |
|
|
|
What are the four steps of translation?
|
1. Initiation2. Elongation
3. Translocation 4. Termination |
|
|
|
Explain Initiation (four steps)
|
1. Assemble the two subunits of the ribosome (30s + 50s eukaryotic)
2. mRNA at the 5' end attaches to the ribosome. 3. Ribosome moves along until it finds the start codon (AUG) 4. First tRNA arrives carrying methionine amino acid (first contact is at the P site) |
|
|
|
Explain Elongation (2 steps)
|
5. Second tRNA arrives in the A site carrying a comlementary amino acid to the mRNA strand.
6. The first tRNA transfers its amino acid to the second tRNA which creates an amino acid chain. Note: two amino acids are held together using a peptide bond. |
|
|
|
Explain Translocation (4 steps)
|
7. The ribosome moves over one codon.
8. First tRNA (unloaded) moves into the E site which can now exit the ribosome. The tRNA holding the dipeptide chain moves into the P site, leaving the A site open. 9. Another tRNA attaches to the empty A site and the process repeats 10. Multiple ribosomes can translate a single mRNA sequence simultaneously (forming polysomes) |
|
|
|
Explain termination (3 steps)
|
11. Elongation and translocation continue until the ribosome reaches a stop codon. These codons do not have an amino acid.
12. Polypeptide is released and ribososome disassembles back into subunits. The polypeptide may undergo post–translational modification prior to becoming a functioning protein. 13. Protein is exported to where it has to go |
|
|
|
If a protein is produced the endoplasmic reticulum, what happens next?
|
It is moved to the golgi body where it is modified and then transferred to the cell wall where it exits by exocytosis.
|
|
|
|
What enzyme attaches an amino acid to a tRNA molecule?
|
tRNA Activating enzyme
|
|
|
|
What is the purpose of a nucleosome?
|
–reduce DNA size so it will fit into the nucleus
–marks the genes for transcription –supercoils |
|
|
|
What is a base substitution mutation?
|
A single nitrogenous base change in the DNA sequence that results in a single amino acid change.
E.g. Sickle cell anemia |
|
|
|
Mutations can be________, __________, or _________
|
positive, negative, or neutral
|
|
|
|
Give an example of a base substitution mutation
|
TAC TTT TGA TTC to TAC TAT TGA TTC
One base change causes the amino acid to go from met–lys–thr–lys to met–iso–thr–lys |
|
|
|
What may happen to a protein made from a base substitution mutation?
|
The protein may not function correctly.
|
|
|
|
What is a deletion mutation?
|
A mutation with severe consequences on protein production which is caused by the deletion of a single nitrogenous base.
|
|
|
|
Deletion and insertion mutations are both ________ _________ mutations
|
frame shift
|
|
|
|
Why is a deletion mutation so harmful?
|
It changes all of the amino acids in a protein chain and may lead to nonsense or non functioning proteins.
|
|
|
|
What is an example of a deletion mutation?
|
TAC GGG ATT to TCG GGA TT
The deletion of one base sequence changes the protein from met–pro–stop to ser–pro– No stop codon and no start codon will not allow the production of a polypeptide. |
|
|
|
Why does DNA form a double helix?
|
Because of its antiparallel nature.
|
|
|
|
The promoter is on the ______________ strand
|
antisense
|
|
|
|
What kinds of bonds hold together the sugar, nitrogenous base, and phosphate group in a nucleotide?
|
covalent bonds.
|
|
|
|
What is similar about RNA and DNA?
|
Both are nucleic acids made up nucleotides, which have an extremely similar structure of a phosphate group, a nitrogenous base, and a sugar group.
|
|
|
|
What is a highly repetitive sequence? What is a unique sequence?
|
A highly repetitive sequence is satellite DNA. A unique sequence is a coding sequence.
|
|
|
|
Why is base pairing important in DNA replication?
|
Base pairing is important because complementary base pairing allows DNA to replicate through the use of only one strand (as there is only one nitrogenous base that pairs with another nitrogenous base). Because of this, an exact replicate can be made using one of the parent strands. Semi–conservative replication may occur because of complementary base pairing.
|
|
|
|
Why is base pairing important in transcription?
|
In order to make an RNA replicate of the sense strand, the antisense strand is used as a template. Complementary base pairing allows for a transcript to be made from the sense strand's complementary strand, ensuring accuracy and efficiency.
|
|
|
|
How is base pairing important in protein synthesis?
|
Complementary base pairing gives tRNA molecules a mechanism in which they can pair up the correct amino acids. By carrying an anti–codon that pairs with a specific amino acid, the mRNA code may be "read" and the correct amino acid may be paired up, as the anticodon will pair up with the codon due to complementary base pairing.
|
|
|
|
When DNA is given in a sequence, it is always the _____________ strand unless otherwise specified.
|
antisense
|
|
|
|
The cell theory states that: |
1. All living things are composed of cells (or cell products) 2. The cell is the smallest unit of life 3. Cells only arise from pre-existing cells |
|
|
|
How are microscopes evidence of cell theory? |
-microscopes have allowed humans to view tiny objects -all living things have been found to be made of cells when examined with a microscope. |
|
|
|
Certain types of cells are exceptions to the general cellular structure. What are these? |
-Muscle cells which have multiple nuclei -Fungal hyphae which have multiple cells but a continuous cytoplasm |
|
|
|
What is the difference between a light and electron microscope? |
-light microscopes are the type that are used in schools. They use light and can view tiny objects. -electron microscopes are the type that are used in professional labs. They used electrons to view very tiny objects. |
|
|
|
How have experiments supported the cell theory? |
-Cells removed from tissues survive independently for short periods of time. (1) -Nothing smaller than a cell has been found to be able to live independently (2) -Experiments by Francesco Redi and Louis Pasteur have shown that cells cannot grow in sealed and sterile conditions. (3) |
|
|
|
What are some examples of unicellular organisms? |
Amoeba, paraceium, euglena, and bacterium |
|
|
|
What seven characteristics do all living things share? |
Mrs. Gren -Movement (external or internal) -Reproduction: asexual or sexual -Sensitivity: respond and interact with environment -Growth: Can grow/change shape -Respiration: Use abiotic material to make energy -Excretion: remove wastes -Nutrition: exchange materials and gases with the environment |
|
|
|
What are the units used measure cells? |
-micrometre (fancy u) -0.000001 m -millionth of a metre -nanometer (nm) -0.000000001 m -billionth of a meter |
|
|
|
What are the average sizes of: -a molecule -cell membrane thickness -virus -bacteria -organelles -and eukaryotic cells |
molecule: 1 nm cell membrane thickness: 7.5 nm virus: 100 nm (20 - 200 nm) bacteria: 1 - 5 um organelles: <10 um eukaryotic cells: <100 um |
|
|
|
What is the formula for calculating linear magnification of a drawing? |
magnification = measured size / actual size mag = meas / act |
|
|
|
What is the formula for calculating the actual size when given the magnification? |
act = meas / mag |
|
|
|
Why is surface area to volume ratio an important factor in limiting cell size? |
-metabolic rate is a function of its mass/volume -rate of material exchange is a function of surface area -when a cell grows, volume increases faster than surface area (decreasing SA:Vol ratio) -if metabolic rate > rate of material exchange, cell dies -cell must divide to |
|
|
|
What does glycolysis do? |
-Glycolysis splits glucose into two pyruvate molecules. -uses two ATP to create 4 ATP -convert |
|
|
|
What does Glycolysis do? |
-produces net 2 ATP (uses 2, produces 4) -reduction reaction of NAD+ to NADH -splits glucose into 2 pyruvate |
|
|
|
Where does glycolysis occur? |
In the cytosol (or cytoplasm) |
|
|
|
What occurs in oxidative phosphorylation? |
-NADH gets oxidized to NAD+ (losing electrons) -This releases a lot of energy -Oxygen accepts these electrons and is turned to water (is reduced) -this happens in steps where energy is released when it is accepted enzymes which pump hydrogen protons across a membrane. |
|
|
|
How is ATP produced in oxidative phosphorylation? |
-Electrons go down a gradient in the phospholipid bilayer when proteins in the membrane accept electrons from the oxidation of NADH to NAD+ -creates a proton gradient, more protons on the intermembrane space side. -Then they flow down a protein called ATP synthase, turning a rotor, and causing the creation of ATP. -ADP plus a phosphate group makes ATP |
|
|
|
What are the steps of cellular respiration? Where does each step occur? |
Glycolysis in the cytoplasm Link Reaction in the matrix Kreb's Cycle in the matrix Oxidative Phosphorylation (electron transport chian + chemiosmosis) in the matrix, inner membrane, and intermembrane space |
|
|
|
How much NADH is produced by the link reaction? How much ATP? |
2 and 0 |
|
|
|
How much NADH is produced by glycolysis? how much ATP? |
2 and 2 |
|
|
|
how many times is NAD+ reduced to NADH in the citric acid cycle? |
3 times |
|
|
|
How much NADH is produced in the Kreb's Cycle? How much ATP? |
6 and 2 |
|
|
|
How does cell respiration start? |
A Glucose (hexose) molecule is broken into two pyruvates in glycolysis. |
|
|
|
What is a reduction reaction? |
A reaction where electrons are gained, or oxygen is removed, or hydrogen is gained |
|
|
|
What is an oxidation reaction? |
A reaction where electrons are lost or oxygen is added, or hydrogen is lost. |
|
|
|
What is the most common hydrogen carrier and what is its reduced and oxidized form? |
NAD+, Nicotinamide Adenine Dinucleotide If it goes through a reduction reaction, NADH is produced. If NADH is oxidized, NAD+ is produced |
|
|
|
What is the less frequent hydrogen carrier and what is its reduced and oxidized form? |
FAD, Flavin Adenine Dinucleotide If it goes through a reduction reaction, FADH2 is produced. If FADH2 is oxidized, FAD is produced |
|
|
|
What is an electron/hydrogen carrier? |
A molecule that is capable of accepting electrons/hydrogen ions from another molecule (electron donor) and then transport these electrons to donate to another molecule during ETC. E.g. NADH and FADH2 are co-enzymes that source electrons (and H+) in ETC Think of them as tickets for creating ATP |
|
|
|
Describe the first step of Glycolysis. |
Substrate level phosphorylation: -Glucose is phosphorylated to create Fructose 1,6 bisphosphate. -It is a six carbon molecule with a phosphate group on carbon 1 and 6 (making it unstable) -this requires the investment of 2 ATP. ATP is oxidized to give the energy to bond, producing 2 ADP + Pi |
|
|
|
Describe the second step of glycolysis. |
Lysis: -The Fructose 1,6 bisphosphate splits into two 3 carbon molecules called: -glyeralaldehyde 3 phosphate/PGAL/triose phosphate (TP) |
|
|
|
Describe the third step of glycolysis. |
Oxidation: -Another phosphate group is added to the PGAL -Oxidation removes hydrogen, which is used to reduce NAD+ to NADH -2 NADH are produced |
|
|
|
Describe the fourth step of glycolysis. |
ATP formation: -Through the reduction of 2 ADP + Pi to 2 ATP on each 3 C molecule, 4 ATP total are produced -As well, a 3C molecule called a pyruvate is formed. |
|
|
|
What is the result of glycolysis? |
2 NADHs 2 net ATP (4 gross ATP) 2 3C pyruvates |
|
|
|
Why are phosphate groups added to molecules in glycolysis? |
Phosphorylation, (the addition of phosphorous to a hydrocarbon or ADP molecule), makes a molecule less stable. This allows reactions to proceed faster without needing to use energy. |
|
|
|
What occurs in the link reaction? |
-A pyruvate binds with Coenzyme A through the decarboxylation and oxidation of of the pyruvate. -This occurs through the reduction of NAD+ to NADH H+ -the waste product is CO2. -the product is Acetyl CoA (2C), which can be used in the Kreb's cycle |
|
|
|
What is the product of the link reaction? |
-2 CO2 per glucose molecule -2 NADH per glucose molecule -2 Acetyl CoA per glucose molecule |
|
|
|
How can fatty acids be used in cell respiration? |
-glycolysis is not needed -fatty acid jumps to the link reaction, where CoA oxidises the long carbon chain of fatty acids. -the reaction is slower |
|
|
|
In the Kreb's cycle, how is citric acid produced? |
Acetyle CoA (2C) and Oxaloacetate (4C) bind, producing CoA and Citric Acid. The CoA can no bind with another pyruvate in the link reaction. |
|
|
|
In the Kreb's cycle, how is citric acid turned into a 5 carbon molecule? |
-Citric acid is oxidized into a 5 carbon molecule, producing a CO2 molecule (this reaction is called decarboxylation) and an NADH. -A reduction reaction is what causes the oxidation of citrate. NAD+ is reduced to NADH. |
|
|
|
In the Kreb's cycle, how is the 5 carbon molecule turned into a 4 carbon molecule? |
-The molecule is oxidized into a 4 carbon molecule through: -The substrate-level phosphorylation of ADP + Pi to ATP -The decarboxylization of CO2 -and the reduction of NAD+ to NADH |
|
|
|
In the Kreb's cycle, how is the 4 carbon molecule modified to create oxaloacetate? |
-The 4 carbon molecule is modified into oxaloacetate through: -the reduction of FAD to FADH2 -and the reduction of NAD+ to NADH |
|
|
|
Why is the Kreb's cycle a cycle? |
It starts and ends with the same molecule: oxaloacetate, so the process can keep repeating over and over. |
|
|
|
How many CO2, NADH, ATP, and FADH2 are produced from the Kreb's cycle per glucose molecule? |
-4 CO2 (2 per spin) -6 NADH (3 per spin) -2 ATP (1 per spin) -2 FADH2 (2 per spin) |
|
|
|
Why is it important that NADH and FADH2 are produced from the Kreb's cycle? |
They are like the tickets to make ATP in the ETC. They carry H+ ions and electrons which are responsible for the ETC in the cristae. |
|
|
|
What is the first step of oxidative phosphorylation? |
Electron transport chain: -NADH is oxidized, releasing 2 electrons into the inner membrane and a protein pumps 2 hydrogen ions into the intermembrane space -the electron jumps between integral proteins like ubiquione and cytochrome III, following the energy gradient. -Energy is released from the electrons as they move down -This activates protein channels which pump H+ ions through the cristae into the intermembrane space. |
|
|
|
When does FADH2 come into play in electron transport chain? |
-FADH2 is used only at lower energy levels along ETC and donates 2 electrons as well. |
|
|
|
What is the second step of oxidative phosphorylation? |
Chemiosmosis: -Pumping of carrier proteins (activated by electons moving along the electron transport chain) cause a high H+ conc. in the intermembrane space -Osmosis: areas of high conc. want to move to areas of low conc. -H+ ions flow through ATP synthase enzyme, causing it to spin. -Spinning ATP synthase catalyzes the phosphorylation of ADP + Pi to make a maximum of 34 ATP |
|
|
|
How can chemiosmosis be compared to a dam? |
-The inner membrane is the damn -The ATP synthase enzyme is the turbine -The H+ in the intermembrane space is the high water level on one side of the dam -The H+ in the matrix is the low level water level on the other side of the dam -When water spins the turbines, energy is created -When H+ spins the ATP synthase, ATP is created |
|
|
|
On average, how much ATP do NADH and FADH2 yeild per glucose molecule in oxidative phosphorylation? |
1 NADH yields 3 ATP. 10 NADH produce 30 ATP 2 FADH2 yeilds 2 ATP. 2 FADH produce 4 ATP This amounts to 34 ATP produced by oxidative phosphorylation. |
|
|
|
Why is oxygen important in the ETC? |
Oxygen is the terminal electron acceptor. It maintains the concentration gradient of H+ and removes electrons by forming water from 1/2 O2 + 2H+ 2 e-. This needs to happen in order for the ETC to continue. |
|
|
|
Compare aerobic and anaerobic respiration. |
Aerobic vs Anaerobic -greater ATP yeild vs low ATP yield -goes through glycolysis to OP vs goes through glycolysis only -end product is 38 ATP vs end product is lactic acid or ethanol and 2 ATP -glycolysis yields 2 ATP, 2 NADH, and 2 pyruvate vs glycolysis yields 2 ATP, 2 ethanol/lactate, and 2 CO2 -uses oxygen vs doesn't use oxygen -both modes of generating energy that need glucose |
|
|
|
What is the difference between substrate-level phosphorylation and oxidative phosphorylation? Where can both of them be found? |
??? |
|
|
|
What is the difference between substrate-level phosphorylation and oxidative phosphorylation? |
SLP vs OP Occurs in glycolysis and krebs vs occurs due to chemiosmosis Phosphorylation of ATP due to the direct phosphorylation of ADP by an intermediate vs phosphorylation of ADP with Pi and chemiosmosis |
|
