Exam 3 - Most Missed Questions and Quizzes Flashcards
Which fatty acid is commonly attached to soluble proteins to allow membrane localization?
A) eicosapentaenoic acid (EPA)
B) farnesylic acid
C) myristic acid
D) linoleic acid
E) arachidonic acid
C) myristic acid
Of the major lipoproteins, ________ are highest in cholesterol and cholesterol esters while ________ are highest in triacylglycerols.
A) LDL; chylomicrons
B) HDL; VLDL
C) VLDL; LDL
D) chylomicrons; HDL
E) LDL; VLDL
A) LDL; chylomicrons
During β-oxidation in the peroxisome, what reoxidizes the enzyme-bound FADH2 during the first oxidation of the pathway?
A) FMN
B) O2
C) NAD+
D) H2O2
E) none of the above
B) O2
When the transaminase enzyme is in the ________ form, it will only react with ________.
A) pyridoxal; α-amino acid
B) pyridoxal; β-keto acid
C) pyridoxal; α-keto acid
D) pyridoxamine; α-amino acid
E) pyridoxamine; β-amino acid
A) pyridoxal; α-amino acid
The hydrolysis of triacylglycerols stored in adipose tissue is catalyzed by the enzyme ________.
A) chylomicron lipase
B) hormone-sensitive lipase
C) albumin-associated lipase
D) lipoprotein lipase
E) adipocyte lipase
B) hormone-sensitive lipase
Identify the compound below.
A) ceramide
B) glycerophospholipid
C) ganglioside
D) sphingosine
E) spingomylelin
E) spingomylelin
For every two electrons transferred from NADH to oxygen, ________ protons are pumped from the matrix to the intermembrane space.
A) 6
B) 8
C) 10
D) 4
E) 12
C) 10
What enzyme is the major control point of cholesterol synthesis in humans?
A) HMG-CoA lyase
B) isopentenyl pyrophosphate synthase
C) thiolase
D) HMG-CoA synthase
E) HMG-CoA reductase
E) HMG-CoA reductase
Which of the following statements describes integral membrane proteins?
A) their association with the membrane is through an attached fatty acyl or prenyl group
B) they are easily removed by changes in pH or high salt
C) they tend to be water soluble
D) they never completely span the lipid bilayer
E) the amino acids that contact the core of the membrane are hydrophobic
E) the amino acids that contact the core of the membrane are hydrophobic
After depolarization of a nerve cell, what event restores the resting potential?
A) K+ influx
B) Cl- efflux
C) Na+ influx
D) K+ efflux
E) Na+ efflux
D) K+ efflux
D-Glucose and D-Mannitol are similarly soluble, but D-Glucose is transported through the erythrocyte membrane four times as rapidly as D-Mannitol. What is the most likely explanation?
A) D-Glucose flux through the membrane is linear, whereas D-Mannitol flux is described by a hyperbolic curve.
B) D-Glucose and D-Mannitol are transported via a system that distinguishes the two sugars.
C) D-Glucose and D-Mannitol enter the erythrocyte via an ion-gated channel.
D) D-Glucose undergoes simple diffusion more rapidly than D-Mannitol because glucose is less polar.
E) None of the above provides the explanation.
B) D-Glucose and D-Mannitol are transported via a system that distinguishes the two sugars.
Ubiquinone is a ________ molecule that serves as a ________ electron carrier; cytochrome c is a ________ molecule that serves as a ________ electron carrier.
A) hydrophilic; 2; hydrophobic; 1
B) hydrophobic; 1; hydrophilic; 2
C) hydrophilic; 2; hydrophobic; 2
D) hydrophobic; 1; hydrophilic; 1
E) hydrophobic; 2; hydrophilic; 1
E) hydrophobic; 2; hydrophilic; 1
What free radical is thought to be commonly produced by the electron transport chain?
A) peroxyl, ROO∙
B) hydroxyl, HO∙
C) hydrogen peroxyl, H2O2∙
D) superoxide, O2∙
E) all of the above
D) superoxide, O2∙
In the electron transport chain, electrons are passed from redox center to redox center ________.
A) because of the proton gradient
B) spontaneously because of the redox potential gradient
C) in an ATP dependent fashion
D) with the assistance of a carrier protein
E) because of the addition of free energy
B) spontaneously because of the redox potential gradient
To oxidize the fatty acids in a triacylglycerol, what must occur first?
A) transport into the mitochondria
B) fatty acid activation
C) lipolysis
D) oxidation of a carbon-carbon single bond to an alkene
E) none of the above
C) lipolysis
In the β-oxidation pathway, the oxidation occurs at carbon ________ with the acetyl group that becomes acetyl-CoA derived from the ________ end of the fatty acid.
A) 2; carbonyl
B) 1; methyl
C) 3; carbonyl
D) 1; carbonyl
E) 2; methyl
C) 3; carbonyl
How many photons of light must be absorbed by photosystem II to produce one molecule of oxygen?
A) 4
B) 8
C) 16
D) 1
E) 2
A) 4
All are properties of uncouplers EXCEPT:
a. They dissipate the proton gradient.
b. ATP/ADP ratio increases.
c. Electron transport continues.
d. They were briefly used as weight-loss drugs.
e. Heat is produced.
b. ATP/ADP ratio increases.
Membrane fluidity is influenced by
a) van der Waals contacts
b) acyl chain length
c) degree of acyl chain saturation
d) cholesterol concentration in membrane
e) all of the above
e) all of the above
proteins linked to a lipid-carbohydrate groups are most likely on the ________ side.
a) extracellular
b) intracellular
c) either intracellular or extracellular
a) extracellular
what is responsible for the extremely rapid propagation of axon potential?
a) Na+ channels open quickly to allow Na+ to flood into the cell
b) K+ channels close quickly to prevent K+ leaving the cell
c) axons are insulated with myelin sheath which prevents ion movement except at the nodes between the myelinated sheaths
d) K+ channels open quickly to allow K+ ions to enter the cell
c) axons are insulated with myelin sheath which prevents ion movement except at the nodes between the myelinated sheaths
the Na+/K+ transporter is an example of
a) passive transport
b) active transport
c) an antiporter
d) a symporter
e) both B and C
e) both B and C
the concentration of cytosolic K+ is ______ the extracellular concentration.
a) dependent upon
b) less than
c) the same as
d) greater than
e) linearly related to
d) greater than
which sequence shoes the correct order of mitochondrial electron transport?
a) ubiquinone –> complex III –> cytochrome c
b) cytochrome b –> NAD+ –> complex I
c) ubiquinone –> NADH –> cytochrome c
d) NAD+ –> O2 –> complex IV
a) ubiquinone –> complex III –> cytochrome c
O2 is converted to H2O _______
a) at each step of electron transfer
b) as part of the Q cycle
c) in complex IV
d) in complexes I, III, and IV
c) in complex IV
During fuel abundance, excess ____ is (are) catabolized to
acetyl-CoA , which is used in fatty acid synthesis.
a) glucose
b) amino acids
c) nucleotides
d) A and B
e) A, B, and C
d) A and B
Insulin is released from pancreatic ___ cells in response to ____
blood glucose.
a) β; low
b) β; high
c) α; low
d) α; high
b) β; high
Which enzyme is the better sensor of glucose concentration?
a) Hexokinase
b) Glucokinase
b) Glucokinase
The initial effect of insulin binding on muscle cells is the
translocation of ____.
a) GLUT4
b) β-adrenergic receptors
c) α-adrenergic receptors
d) adenylate cyclase
e) G proteins
a) GLUT4
Which of the organs listed below has the capacity to generate
glucose through gluconeogenesis?
a) Liver
b) Muscle
c) Adipocytes
d) Kidneys
e) A and D
e) A and D
Which cycle is properly paired with its purpose?
a) The Cori cycle functions to transfer nitrogens to the liver.
b) The glucose-alanine cycle functions to break down glycogen in
the liver.
c) The Cori cycle functions to synthesize glucose in the liver to
replenish glucose in muscle.
d) The glucose-alanine cycle returns alanine from the liver to the
muscle.
e) None of the above is correct.
c) The Cori cycle functions to synthesize glucose in the liver to
Glycogen phosphorylase is allosterically ______ by ATP.
a) activated
b) inhibited
c) not affected
b) inhibited
The hormone ______ stimulates the liver to generate glucose by
glycogenolysis and gluconeogenesis.
a) epinephrine
b) norepinephrine
c) insulin
d) glucagon
e) leptin
d) glucagon
The hormone ______ stimulates lipolysis in adipocytes.
a) epinephrine
b) norepinephrine
c) insulin
d) glucagon
e) leptin
d) glucagon
The hormone ______ stimulates muscle to generate glucose by
glycogenolysis.
a) epinephrine
b) norepinephrine
c) insulin
d) glucagon
e) leptin
a) epinephrine
