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43 Cards in this Set
- Front
- Back
3 things nucleotides have |
Nitrogenous base. Sugar. Phosphate group. |
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RNA structure |
Single strand. A and U. C and G. Ribose |
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mRNA |
Directs protein synthesis (carries instructions for protein synthesis from DNA to the ribsomes) |
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tRNA |
Transfer RNA. Transports/carries amino acids to the ribosomes (to be added to a protein during protein synthesis) |
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rRNA |
Ribsosomal RNA. Makes up a ribsome |
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Transcription |
DNA to mRNA. Occurs in nucleus. Steps: initiation, elongation, termination. |
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Translation |
RNA to protein. Happens in the cytoplasm at the ribosomes. |
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4 Structures needed for translation |
Ribosomes, mRNA, tRNA, amino acids |
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Steps for translation |
Initiation, elongation, termination, protein is folded and further modified by rough ER and golgi appartus. |
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Mutations |
Errors in the DNA sequence. These will usually change the protein and prevent it from forming results in disease or death. |
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Mitosis |
Prophase, metaphase, anaphase, telophase. |
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Interphase |
Period when cell is not dividing. G1, s phase, g2. DNA is replicated in s phase. |
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Meiosis |
Occurs in sex cells. Cell divides twice to reduce chromosome number in half. Yields 4 haploid cells. FSH, sex hormones and inhibin control meiosis. |
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Genetics |
Study of inheritance |
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Homologous chromosomes |
A pair of chromosomes that control the same traits but not necessarily the same alleles |
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Diploid |
Cell contains both chromosomes of each homogolous pair. All cells have 46 chromosomes except gametes. |
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Haploid |
Cell contains 1 chromosome of each homogolous pair. Gamete (sperm/egg) have 23 chromosomes. |
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Law of dominance |
A dominant allele masks the expression of a recessive allele in a gene pair. Ex: Bb |
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Principle of segregation |
Allele pairs separate when gametes are formed. Each gamete receives one allele fir each trait. |
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Principle of independent assortment |
Traits carried on separate chromosomes are inherited independently of one another. Results in more genotypes. |
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Incomplete dominance |
Neither allele dominates so both are partially expressed. Ex: sickle cell trait, flower color |
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Codominance |
Two alleles are equally dominant Ex: blood type |
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Polygenic inheritance |
Combined effect of 2 or more genes |
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Sex linked traits |
Abnormal gene on x chrom., shows up more often in males since the y chrom can't mask the x Ex: color blindness, hemophilia |
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Sex influenced trait |
Gene is dominant in males and recessive in females. Ex baldness |
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Complex inheritance |
Combined effects of many genes and environmental factors, results in a wide variety of phenotypes. Ex skin color, hair, eyes, height |
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Rh incompatibility |
Rh+ is dominant, Rh- is recessive. Happens when mom is negative and fetus is positive in second etc pregnancies. |
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Genetic abnormalities |
If mutations happen in gametes. 1 in 12 pregnancies have this and end in miscarriage. 1 in 150 births has a chromosomal aberration. |
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Aneuploidy |
Abnormal number of chromosomes. Not 46 |
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Monosomy |
Missing one chromosome. Usually not fatal |
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Polysomy |
One or more extra chrom. Death or severe disabilities |
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Nondisjuction |
Chromosomes fail to separate during meiosis. One gamete ends up with 24 and one with 22 chrom. |
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Anaphase lag |
One chrom lags behind during meiosis and is left out of the cell. Ex 23 and 22 |
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Examples of aneuploidy |
Down syndrome: Extra chrom 21 from nondisjuction during oogenesis. Trisomies of other chrom don't survive. |
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Abnormal chromosome structure |
Right number of chromosomes but wrong structure. Usually happen during crossover in meiosis. |
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Translocation |
Crossover occurs between nonhomolgous chrom. Eg swapping genes with a different trait |
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Inversion |
Genes are in the wrong order |
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Deletion |
Loss of a portion of a chromosome |
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Duplication |
A portion of a chrom is duplicated |
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Mendelian single gene disorders |
Mutations of single genes, which then code for abnormal enzymes, structural proteins or regulatory proteins. 85% are inherited. |
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Autosomal dominant disorders |
Single gene disorder. The abnormal allele is dominant so only one copy of the affected allele is needed to have the disease. Ex. Huntingtons |
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Autosomal recessive disorders |
Single gene disorder. The abnormal gene is recessive so two copies of the affected allele are needed to have the disease. If you are heterozygous that makes you a carrier. Ex. Tay sachs |
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Triple repeat mutations |
Many extra repeating triplets of DNA bases |