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68 Cards in this Set
- Front
- Back
List 4 similarities between the citric acid cycle and beta oxidation.
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1) cycles only occur under aerobic conditions
2) both occur entirely only in the mitochondria 3)at least some intermediates are processed as coenzyme-A thioesters 4)hydrogen is extracted from a C-C single bond to yield a C=C double bond using FAD as the cosubstrate |
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What amino acids can be degraded to energy-rich metabolites?
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All standard amino acids can be degraded in human metabolism.
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The sulfonylurea receptor is a __________ that mediates __________. When activated by its ligand, it causes ___________. The receptor and its associated ion channel are controlled by ________.
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- a membrane protein associated with a potassium ion channel
-mediates secretion of insulin -when activated it causes the cell membrane to depolarize -the receptor & the ion channel are controlled by ATP; high levels of ATP lowers the permeability of the ion channel |
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The rate of insulin secretion is _________ when blood glucose is high.
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The rate of insulin secretion is high when blood glucose is high.
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The key energy-rich compound in human energy metabolism is ____.
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ATP (adenosine triphosphate)
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Carbon atoms that are oxidized in the TCA may enter it as _____ or _____.
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acetyl-CoA or in the form of TCA intermediates
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Acetyl-CoA is formed in the following reaction:
_____ + _____ --> 2 acetyl-CoA This is catalyzed by _______. |
acetoacetyl-CoA + coenzyme A --> 2acetyl-CoA
thiolase |
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Beta-oxidation produces substrates for _______.
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the citric acid cycle because fatty acids are broken down to Acetyl-CoA
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Aspartate is a precursor for __________ in the _____ cycle.
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ornithine
urea cycle |
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Glucogenic amino acids can be degraded to _______ or an intermediate in the _______ Cycle.
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pyruvate
Krebs cycle |
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Ketogenic amino acids produce ketones when energy sources are low: some are degraded directly to _________ such as _______, or converted to acetyl CoA.
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- ketone bodies such as acetoacetate that can be used as fuel in the brain and muscle
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Acetacetate cannot be used in __________, since acetyl CoA cannot be converted directly to __________.
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-gluconeogenesis
-cannot be converted directly to oxaloacetate. |
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In humans,some examples of glucogenic amino acids are ...?
2 ketogenic amino acids? Both keto and glucogenic? |
-serine, arginine, cysteine, proline, glutamate, aspartate
-lysine & leucine -phenylalanine threonine, isoleucine,tryptophan and tyrosine |
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Ketogenic amino acids produce ketones when energy sources are low: some are degraded directly to _________ such as _______, or converted to acetyl CoA.
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- ketone bodies such as acetoacetate that can be used as fuel in the brain and muscle
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Acetacetate cannot be used in __________, since acetyl CoA cannot be converted directly to __________.
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-gluconeogenesis
-cannot be converted directly to oxaloacetate. |
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In humans,some examples of glucogenic amino acids are ...?
2 ketogenic amino acids? Both keto and glucogenic? |
-serine, arginine, cysteine, proline, glutamate, aspartate
-lysine & leucine -phenylalanine threonine, isoleucine,tryptophan and tyrosine |
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Cholesterol and sunlight can form _____.
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Vitamin D.
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What is the precursor to bile salts and steroid hormones?
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Cholesterol.
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What happens when a person fasts (low carbohydrate diet or high fat)?
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Malonyl CoA (synthesis) decreases and in turn Carnitine transferase (oxidation) activity increases
oxaloacetate increasingly used for gluconeogenesis since no glycolytic energy demands. Thus TCA cycle slows, meaning Citrate concentration will decrease and Acetyl CoA will accumulate. Alternative uses for Acetyl CoA begin including production of ketone bodies and thier increased use in the brain. Ketone production increases found in urine and result in urine acidosis and loss of Na ions. |
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Acetyl-CoA carboxylase is _____ by citrate and ______ by epinephrine.
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activated by citrate
inhibited by epinephrine |
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Beta oxidation occurs in the _________, while fatty acid synthesis mostly occurs in ________.
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beta-oxidation in the mitochondria
FA synthesis in the cytoplasm The acetyl CoA is inside the mitochondria and must be shuttled out of the mitochondria for fatty acid synthesis |
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If DNA was replicated in a conservative way Meselson and Stahl's experiment would have had a different result. They would have found _____ bands inthe ______ generation.
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two bands in the first and second generation
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The Meselson-Stahl experiment was an experiment by Matthew Meselson and Franklin Stahl which demonstrated that DNA replication was _______ .
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semiconservative
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Semiconservative replication means
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when the double stranded DNA helix was replicated, each of the two double stranded DNA helices consisted of one strand coming from the original helix and one newly synthesized
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During DNA replication nucleotides are added to to the growing chain at the
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OH group at the 3' end
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The enzymes that stabilize the DNA fork upstream during replication are called
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gyrases
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Okazaki fragments are
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short fragment of DNA (with an RNA primer at the 5' terminus) found on the lagging strand
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bidirectional replication is ______ in eukaryotes and prokaryotes?
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the same
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A mutational change in the third base of a codon is unlikely to make a change in the resulting amino acid sequence because of
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the degeneracy of the code
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post-transcriptional processing in eukaryotes
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5' end cut and 7mG cap added
introns excised and exons spliced together 3' end cut at AAUAA |
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Ames test is _______ to assess the _________ of chemical compounds.
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a biological assay using Salmonella typhimurium that carry mutations in genes involved in histidine synthesis; require histidine for growth
mutagenic potential |
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The tester strains used in the Ames test are specially constructed
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to have both frameshift and point mutations in the genes required to synthesize histidine
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What is the variable being tested in the Ames test?
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the mutagen's ability to cause a reversion to growth on a histidine-free medium
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How do you conduct the Ames test?
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bacteria spread on agar plate with small amount of histidine - allows the bacteria to grow and have the opportunity to mutate; when histidine is depleted only bacteria mutated to gain the ability to produce histidine survive
plate incubated for 48 hours mutagenicity of substance proportional to number of colonies observed |
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One strategy that eukaryotic organisms have evolved to supply cells with lots of ribosomes during periods of heavy protein synthesis is to have
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many repeats of rRNA genes in the genome
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Where on the ribosome will the first charged tRNA with the anticodon UAC attach?
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P site of the small subunit
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For a new mutation to be important in the evolution of an organism (to give an organism a selective advantage in it's phenotype). The mutation must be
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in the gametic cell line
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If a single mutation causes several amino acids in a protein to change it is probably going to be a
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frameshift mutation
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do not result in a change to the amino acid sequence of a protein; may occur in non-coding region (outside of a gene or within an intron), or within an exon but w'out altering the final amino acid sequence
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silent mutation
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single base substitution, is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide
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point mutation (transitions & transversions)
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replacement of a purine base with another purine or replacement of a pyrimidine with another pyrimidine
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transitions
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replacement of a purine with a pyrimidine or vice versa
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transversions
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point mutations, code for a stop, which can truncate the protein
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nonsense mutations:
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more common than
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Transition mutations are about an order of magnitude __________ transversions.
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point mutations, code for a different amino acid
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missense mutations
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what mutation causes sickle-cell disease?
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sickle-cell disease is caused by a single point mutation (a missense mutation) in the beta-hemoglobin gene that converts a GAG codon into GTG, which encodes the amino acid valine rather than glutamic acid.
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Which is the main enzyme involved in E. coli DNA replication?
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DNA Polymerase III
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The presence of nucleosomes complicates ______ in eukaryotes.
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RNA transcription
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Eukaryotes have more kinds of ______ than prokaryotes.
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RNA polymerase
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There are more _____ involved in the gene expression of eukaryotic genes than prokaryotic genes
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receptors
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Somatic mutations are expressed only if they are ______.
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dominant
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Somatic mutations are _______ from generation to generation.
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not passed down
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Gametic mutations are ____ compared to somatic mutations.
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rare
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This sequence is likelly to form pyrimidine dimers & cause a mutation in subsequent generations of DNA
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C-C
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When the lac operon is transcribed, RNA polymerase initially interacts with a stretch of DNA called the
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promoter
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When lactose is present in E.coli it binds to the
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repressor molecule
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A merodiploid is formed with an F plasmid that carries the complete lac operon. The bacterial genome carries a constitutive mutation in the lac operon operator. Will there be beta galactosidase activity if lactose is absent?
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Yes, because the mutation in the bacterial operator will cause transcription to occur all the time.
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type of eukaryotic regulatory molecules have regions that interacts with DNA
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activators
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types of of DNA-binding protein domain
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helix-turn-helix region
leucine zipper zinc finger |
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Alkaptonuria is caused by a build-up of
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homogentisic acid
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Wildtype Neurospora crassa that can grow on minimal media are called
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prototrophic
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The mutational change that produces the abnormal beta globin molecule and causes the disease sickle-cell aneamia could be described as a
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missense mutation
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The most common CF mutation, causes the abnormal gene product to
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get stuck in the endoplasmic reticulum and never reach the cell membrane
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The most common mutational change that creates a CF allele could be described as a
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deletion
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The trp operon is
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a repressible, negatively controlled operon
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RNA polymerase in eukaryotes combines with the ______.
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basal factors
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Allele frequencies for a gene with two alleles can be calculated from a population that is not in H-W equilibrium if
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heterozygotes have a distinctive phenotype
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assumptions of H-W equilibrium
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Large population size
Random mating No migration |