Term
What is the rate-limiting step in fatty acid synthesis?
A. the condensation step of fatty acid synthase
B. cleavage of the fatty acid from the acyl carrier protein (ACP)
C. attachment of a malonyl group to the acyl carrier protein (ACP)
D. the formation of malonyl-CoA |
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Definition
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Term
Which of the following lipids or lipid-derived molecules has a glycerol backbone?
A. sphingomyelin
B. cerebroside
C. estrogen
D. plasmalogen |
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Definition
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Term
If malonyl-CoA is synthesized from 14CO2 and unlabeled acetyl-Coa, and the labeled malonate is then used for fatty acid synthesis, the final product will have radioactive carbon in:
A. no part of the molecule
B. every even-numbered C-atom
C. only the omega-carbon atom (farthest from C-1)
D. every C |
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Definition
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Term
The assimilation of CO2 into organic compounds in green plants:
A. takes place in the cytosol
B. takes place at equal rates in light and darkness
C. requires NADPH
D. involves the condensation of the 2 carbon compound acetate with CO2 to form 3-PG
E. results in the production of ATP |
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Definition
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Term
The compound that condenses with CO2 in the first reaction of carbon dioxide assimilation is:
A. rubisco
B. ribulose 5-phosphate
C. ribose 1,5-bisphosphate
D. 3-phosphoglycerate
E. ribulose 1,5-bisphosphate |
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Definition
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Term
the rate-limiting step in fatty acid synthesis is:
A. formation of acetyl-CoA from acetate
B. reduction of acetoacetyl group for a B-hydroxybutyryl group
C. condensation of acetyl-CoA and malonyl-CoA
D. formation of malonyl-CoA from malonate and coenzyme A
E. the reaction catalyzed by acetyl-CoA carboxylase |
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Definition
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Term
Which of the following is not true of the reaction producing malonyl-CoA during fatty acid synthesis?
A. It requires CO2
B one molecule of ATP is converted to ADP+Pi for each malonyl-CoA synthesized
C. It requires acyl carrier protein (ACP)
D. The cofactor is biotin
E. It is stimulated by citrate |
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Definition
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Term
The synthesis of both glycerophospholipids and triacylglycerols involves:
A. phosphatidate phosphatase
B. CDP-choline
C. phosphatidic acid
D. phosphoethanolamine
E. CDP-diacylglycerol |
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Definition
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Term
In C4 plants of tropical origin, the first intermediate into which 14CO2 is fixed is
A. malate
B. phosphoenolpyruvate
C. 3-phosphoglycerate
D. aspartate
E. oxaloacetate |
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Definition
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Term
Which of the following is not an intermediate in the synthesis of lanosterol from acetyl-CoA?
A. HMG-CoA
B. mevalonate
C. malonyl-CoA
D. squalene
E. isopentenyl pyrophosphate |
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Definition
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Term
The synthesis of glycogen, starch, and sucrose all:
A. use glucose-6-phosphate as substrate
B. take place in liver and muscle of mammals
C. use a sugar nucleotide as substrate
D. involve addition of a sugar residue at the reducing end of the growing polymer
E. use glucose 1-phosphate as the only substrate |
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Definition
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Term
Which types of amino acids are both ketogenic and glucogenic?
A. those that are degraded to succinyl-CoA
B. those that are degraded to acetyl-CoA
C. those that are degraded to pyruvate
D. those that are degraded to oxaloacetate
E. none of the above |
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Definition
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Term
5-phosphoribosyl-alpha-pyrophosphate (PRPP) is a synthetic precursor for all of the following except:
A. AMP
B. tryptophan
C. arginine
D. histidine
E. UMP |
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Definition
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Term
Fixation of one molecule of atmospheric N2 by the nitrogenase complex:
A. requires 16 moles ATP
B. requires 8 moles electrons total
C. produces one mole NH4+
D. A and B
E. A, B, and C |
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Definition
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Term
CMP, UMP, and TMP all have ___ as a common precursor.
A. inosine
B. adenosine
C. S-adenosyl methionine
D. glutamine
E. aspartate |
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Definition
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Term
Urea synthesis in mammals takes place primarily in tissues of the:
A. skeletal muscle
B. kidney
C. brain
D. small intestine
E. liver |
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Definition
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Term
The conversion of glutamate to produce an alpha-ketoacid and NH4+:
A. occurs in the cytosol
B. is catalyzed by glutamate dehydrogenase
C. is a reductive deamination
D. requires ATPE. does not require any cofactors |
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Definition
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Term
The hormones epinephrine and norepinephrine are derived biosynthetically from:
A. tryptophan
B. arginine
C. isoleucine
D. histidine
E. tyrosine |
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Definition
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Term
In the urea cycle, arginase catalyzes:
A. formation of citrulline from ornithine and another reactant
B. cleavage of urea to ammonia
C. formation of ornithine from citrulline and another reactant
D. transamination of arginine
E. formation urea from arginine |
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Definition
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Term
Newborn infants sometimes develop jaundice because of an accumulation of
A. urobilin
B. biliverdin
C. bilirubin
D. heme
E. none of the above |
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Definition
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Term
Which of the following processes are carried out in the cytosol?
A. glycolysis, gluconeogenesis, fatty acid synthesis
B. ketogenesis, citric acid cycle, B-oxidation
C. photosynthesis, DNA replication
D. all of the above
E. none of the above |
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Definition
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Term
Which of the following occurs when a presynaptic neuron releases acetylcholine into the synaptic cleft?
A. the acetylcholine receptor channel of the postsynaptic neuron allows outward flux of NA+ ions
B. the acetylcholine receptor channel of the postsynaptic neuron closes.
C. activation of the receptor protein kinase activity results in the activation of additional protein kinases
D. acetylcholine is internalized by the postsynaptic neuron
E. the plasma membrane of the postsynaptic neuron becomes depolarized |
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Definition
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Term
| Which of the following is an application for Scatchard analysis? A. measuring the biological response of a stimulus B. measuring the number of ions that pass through an ion channel C. measuring the affinity of receptor for its ligand D. measuring the amplification of a biological signal E. none of the above |
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Definition
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Term
Insulin action includes:
A.increased glucose transport into cells
B. supression of glycogen breakdown
C. stimulation of triacylglycerol synthesis
D. A and B
E. A B and C |
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Definition
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Term
Which of the following is true about the hormone epinephrine?
A. it causes a derease in blood pressure
B. it stimulates glycolysis in liver and muscle cells
C. it must be present in high concentrations to carry out its actiity
D. its intracellular signal persists long after it has stopped binding its receptor
E. it promotes the mobilization of glucose from glycogen |
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Definition
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Term
Which signal input is matched correctly with the result?
A. epinephrine- sensory cell depolarizes
B. light- sensory cell depolarizes
C. sweet molecule- no effect on sensory cell membrane potential
D. odorant- sensory cell depolarizes
E. none of the above |
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Definition
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Term
Of the two types of diabetes, which of the following situations is unique to type 2 diabetes?
A. inability to produce sufficient insulin
B. inability to take up glucose efficiently from the blood
C. inability to respond to insulin (insulin resistance)
D. presence of glucose in the urine
E. requires administration of insulin |
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Definition
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Term
What do the detection of hormones and sensory stimuli have in common?
A. a change in the concentration of a second messenger
B. detection is communication through hyperpolarization of hte plasma membrane
C. adenylyl cyclase is activated
D. receptors for those stimuli are found on neurons
E. a change in the activity of PKA |
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Definition
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Term
The B-cells of the islets of Langerhans secrete __ in response to __ glucose levels, the alpha-cells release __ in response to __ glucose levels.
A. insulin, low; glucagon, low
B. glucagon, high; insulin high
C. insulin, high; glucagon, low
D. glucagon, low; insulin, high
E. none of the above |
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Definition
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Term
Which of the following statements is true?
A. muscle cannot use fatty acids as an energy source
B. fatty acids cannot e used as an energy source in humans because humans lack the enzymes of the glyoxylate cycle
C. amino acids are a preferable energ source over fatty acids
D. in a well-fed human, about equal amounts of energy are stored as glycogen as as triacylglycerol
E. the brain prefers glucose as an energy source, but can use ketone bodies |
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Definition
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Term
During elongation, eukaryotic RNA polymerase is modified by:
A. phosphorylation
B. acetylation
C. cleavage
D. all of the above
E. none of the above |
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Definition
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Term
Base excision repair includes:
A. removal of a damaged base by glycosylase
B. endonuclease cleavage of the damaged DNA
C. gap repair by DNA polymerase
D. A and C
E. A, B, and C |
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Definition
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Term
The sigma factor of E. coli RNA polymerase:
A. is inseparable from the core enzyme
B. is required for termination of an RNA chain
C. will catalyze synthesis of RNA from both DNA template strands in teh absence of the core enzyme
D. associates with the promoter before binding to the core enzyme
E. combines with the core enzyme to confer specific binding to a promoter |
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Definition
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Term
A branched (lariat) structure is formed during:
A. splicing of all classes of introns
B. splicing of group II introns
C. attachment of a 5' cap to mRNA
D. attachment of poly(A) tails to mRNA
E. processing of preribosomal RNA |
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Definition
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Term
PRocessing of a primary mRNA transcript in a eukaryotic cell doesn't normall involve:
A. attachment of a long poly(A) sequence at the 3' end
B. excision of intervening sequences
C. joining of exons
D. conversion of normal bases to modified bases, such as inosine and pseudouridine
E. methylation of one or more guanine nucleotides at the 5' end |
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Definition
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Term
The proofreading function of DNA polymerase involves all of the following except:
A. reversal of the polymerization reaction
B. a 3' to 5' exonuclease
C. a detection of mismatched base pairs
D. phosphodiester bond hydrolysis
E. base pairing |
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Definition
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Term
Synthesis of telomeres requires the enzyme __ which is a type of __
1. ribonuclease, riboprotein
2. ribotelase, ligase
C. telomerase, helicase
D. telomerase, ribonucleoprotein
E. none of the above |
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Definition
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Term
DNA ligase
A. provides the phosphate group needed to form a phosphodiester bond
B. transfers AMP to the 5' phosphate group at a nick
C. catalyzes hte formation of a phosphodiester bond between a 3' phosphate and a 5' hydroxyl group
D. fills in gaps
E. all of the above |
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Definition
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Term
In homologous recombination in E. coli, the protein that moves along a double-stranded DNA, unwinding the strands ahead of it and degrading them is:
A. DNA ligase
B. RecA protein
C. chi
D. recBCD enzyme
E RuvC |
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Definition
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Term
Type II topoisomerases:
A. change the degree of supercoiling of a DNA molecule but not its linking number of DNA
B. always change the linking number in increments of 1
C. require energy from ATP
D. can act on single stranded DNA circles
E. cleave only one strand of duplex DNA |
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Definition
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Term
Posttranslational modifications include:
A) disulfide bond formation and glycosylation
B) phosphorylation and proteolysis
C) N-terminal acetylation
D) A and B
E) A, B, and C |
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Definition
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Term
Ubiquitin-mediated protein degradation in eukaryotes is a complex process, and many of the signals
remain unknown. One known signal involves recognition of amino acids in a processed protein that are
either stabilizing (Ala, Gly, Met, Ser, etc.) or destabilizing (Arg, Asp, Leu, Lys, Phe, etc.), and are located
at:
A) a zinc finger structure in the protein.
B) a helix-turn-helix motif in the protein.
C) the amino-terminus of the protein.
D) the carboxy-terminus of the protein.
E) a lysine-containing target sequence in the protein. |
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Definition
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Term
The DNA binding motif for many prokaryotic regulatory proteins, such as the lac repressor, is:
A) leucine zipper.
B) homeobox.
C) zinc finger.
D) helix-turn-helix.
E) homeodomain. |
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Definition
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Term
When damage to DNA is detected, activated p53 leads to arrest of the cell cycle in what phase?
A) G1
B) M
C) G0
D) G2
E) None of the above. |
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Definition
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Term
Consider the lac operon of E. coli. When there is neither glucose nor lactose in the growth medium:
A) CRP protein binds to the lac operator.
B) repressor is bound to the lac operator.
C) the operon is fully induced.
D) RNA polymerase binds lac promoter and transcribes the lac operon.
E) CRP protein displaces the lac repressor from the lac promoter. |
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Definition
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Term
Which of the following is true of cyclin-dependent kinases (CDKs)?
A) Their activity changes throughout the cell cycle.
B) They are degraded as a result of addition of ubiquitin.
C) They alter the activity of cyclins.
D) They are inactivated by binding to cyclin.
E) All of the above are true. |
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Definition
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Term
Formation of the ribosomal initiation complex for bacterial protein synthesis does not
require:
A) formylmethionyl tRNAfMet.
B) mRNA.
C) GTP.
D) initiation factor 2 (IF-2).
E) EF-Tu. |
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Definition
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Term
Signal sequences are not required on proteins destined
A) for the nucleus.
B) for secretion.
C) for the cytosol.
D) for the lysosome.
E) none of the above. |
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Definition
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Term
Which one of the following is not involved in steroid hormone action?
A) Hormone-receptor complexes
B) Hormone Response Elements
C) Regulation of transcription
D) Zinc fingers
E) All of the above are involved |
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Definition
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Term
Which one of the following types of eukaryotic regulatory proteins interact directly with
enhancer sequences?
A) Repressors
B) TATA-binding proteins
C) Coactivators
D) Activators
E) Basal transcription factors |
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Definition
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Term
If a cell were unable to synthesize or obtain THF, it would probably be deficient in the biosynthesis of:
A. leucine
B. methionine
C. lysine
D. isoleucine
E. serine |
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Definition
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