Biochemistry 2 Final Exam - B

Exam 1

:)

does phosphorylation increase or decrease the activity of glycogen synthase

decrease

pyruvate carboxylase converts pyruvate to what

oxaloacetate (OAA)

NADH can be considered a carrier of 2 _________

electrons

The citric acid cycle converts the carbons of an acetyl group into what

CO2

List 3 small molecules that are allosteric regulators of glycolysis

AMP, ATP, NAD+

Which of the following is not a major metabolic control mechanism:

A. Control of enzyme activity

B. Compartmentation

C. Allosteric diversion

D. Control of enzyme concentration

C. Allosteric diversion

T or F: the general strategy for metabolizing galactose is to turn it into an intermediate in glucose metabolism

True

PFK-1 converts fructose-6-phosphate to what?

fructose-1,6-Bisphosphate

T or F: the citrate synthase reaction is irreversible

True

___________ is the division of metabolism in which complex substances are degraded to simpler molecules

catabolism

List three small molecules that are allosteric regulators of the citric acid cycle

NADH, ADP, ATP

Which of the following does not appear in the overall reaction of glycolysis:

A. 2 ADP

B. 6 O2

C. 2 Pyruvate

D. 2 H2O

B. 6 O2

In glycogen synthesis, glucose is transferred from what nucleotide to a pre-existing glycogen polymer?

UDP-glucose

Reactions that generate citric acid cycle intermediates are known as ___________ reactions

anaplerotic

True or False: gout results from cytosine metabolism

False; purine metabolism

Which of the two mitochondrial membranes is a true barrier to the movement of substances in and out of the mitochondrion?

Inner mitochondrial membrane

Which of the following does not appear in the overall reaction of gluconeogenesis:

a. 2 pyruvate

b. 2 GTP

c. glucose

d. 2 FAD

d. 2 FAD

Are pathways regulated primarily by altering their thermodynamics, their kinetics, or both?

Kinetics

T or F: most reactions of glycolysis are near equilibrium

True

What enzyme releases glucose-1-phosphate from glycogen?

glycogen phosphorylase

What does amphibolic mean?

both catabolic and anabolic

Approximately how many ATP are produced in aerobic catabolism of glucose?

30-32 ATP

Does phosphorylation of pyruvate dehydrogenase increase or decrease its catalytic activity?

decrease

In liver, does the isozyme of hexokinase (hexokinase IV) have a higher or lower Km for glucose compared to the other isozymes of hexokinase?

Higher Km

cAMP is a _______ messenger

secondary

Which of the following does not appear in the net reaction of the citric acid cycle

a. Citrate

b. 2 H2O

c. 2 Co2

d. Acetyl-CoA

a. Citrate

Interconversion of NAD+ and NADH is associated with what general type of chemical reaction?

Redox

List three of the five coenzymes found in pyruvate dehydrogenase complex.

Coenzyme A (CoA)

FAD

NAD+

Fermentation allows glycolysis to continue by regenerating what coenzyme?

NAD+

Which class of biochemical compounds is generally more energy dense, carbohydrates or fats?

fats

THe first five reactions of glycolysis are referred to as the energy ________ phase

investment

T or F: in most cases, metabolically opposing pathways are simply the reverse of each other

F

What small molecule binds to and allosterically activates protein kinase A?

cAMP

T or F: generation of any one citric acid cycle intermediate raises the levels of all of them.

T

Exam 2

:)

When 2 electrons flow through the electron transport chain, how many H+ are transported out of the mitchondria?

10 H+

How is ATP synthase regulated?

it is under respiratory control by its substrates

What is the ultimate precursor for the biosynthesis of cholesterol?

Acetyl CoA

In what part of a eukaryotic cell does oxidative phosphorylation occur?

inner membrane of mitochondria

How many ATP are produced as a result of β-oxidation of palmitoyl CoA?

106

What carries electrons from complex II to complex III?

Coenzyme Q

Which part of ATP synthase is in the inner mitochondrial membrane, F0 or F1?

F0 (F1 is in matrix)

Which lipoprotein synthesized in the liver consists of endogenously produced lipids?

VLDL

What effect does insulin have on blood glucose?

lowers blood glucose

If ΔE°' is positive, what is the sign on ΔG°'?

will be spontaneous so negative (-ΔG°')

How many ATP are hydrolyzed in the biosynthesis of palmitate?

7 ATP

What unusual amino acid is used to carry fatty acids from the cytoplasm to inside the mitochondrion?

carnitine

How many ATP are simultaneously synthesized by ATP synthase?

3 ATP

The malate-aspartate shuttle transports what product from glycolysis into the mitochondria?

NADH

T or F: in humans, cholesterol is catabolized to acetyl CoA.

False (acetyl CoA is the precursor of cholesterol)

Write the overall reaction for flow of electrons from NADH to O2

NADH + 1/2 O2 + H+ --> H2O + NAD+

What general class of enzymes hydrolyzes fatty acids from triglycerides?

lipases

What is the preferred fuel for the brain?

glucose (brain will NOT use fatty acids)

What does ATP synthase transport across the inner mitochondrial membrane?

H+

What 3 compounds are the ketone bodies?

acetone, acetoacetate, β-hydroxybutarate

In what form of diabetes is insulin absent?

Type I

Which of the following is not a carrier of electrons in the electron transport chain?

A. Iron-sulfur proteins

B. Cytochrome k

C. Cytochrome c

D. Coenzyme Q

B. Cytochrome k

How many ATP are produced from glucose under aerobic conditions?

30-32 ATP

What enzyme is the major site of regulation for cholesterol biosynthesis?

HMG-CoA Reductase

Which electron transport chain complex does not transport H+ out of the mitochondrion?

complex II

For saturated fatty acids how many reactions are there in each round of β-oxidation?

4 reactions (dehydrogenation, hydration, dehydrogenation, thiolytic cleavage)

In what organ does ketogenesis occur?

liver

What is the value for P/O ratio for FADH2

1.5 ATP

What product of acetyl CoA carboxylase regulates β-oxidation?

malonyl CoA

What effect does glucagon have on glycogen metabolism in the liver?

causes glycogen breakdown to increase in order to produce glucose to raise levels

Which of the following is not evidence for the chemiosmotic theory?

A. β-oxidation requires aerobic conditions

B. An intact inner membrane is required for oxidative phosphorylation

C. Membranes can establish proton gradients

D. Key electron transport proteins span the inner membrane

A. β-oxidation requires aerobic conditions

Uncouplers dissipate what?

H+ ion gradient across the membrane

When blood insulin levels are high, blood glucagon levels are _______.

low

Exam 3

🙂 (this one)

What catalytic is responsible for degrading polyubiquinated proteins?

26S protease

Tumor _____ proteins act to prevent formation of tumors.

suppressor

Ribonucleotide reductase (RNR) converts UDP to what?

dUDP

Which of the following is not found in the net reaction of the urea cycle?

a) Fumarate

b) 3 ATP

c) HCO3-

d) Uric Acid

d) Uric Acid

What enzyme converts dUMP to dTMP?

thymidylate synthase

List 3 metabolic intermediates from which nonessential amino acids can be synthesized.

OAA, Pyruvate, alpha-ketoglutarate

In what part of the cell does the lysosomal protein degradation system break down proteins?

lysosomes

What enzyme activity is affected by the alpha subunits in epinephrine signaling?

adenylate cyclase

What small molecule is an allosteric regulator of urea production?

(NAG) N-acetylglutarate

True or false: binding of nucleotides to the specificity site of ribonucleotide reductase alters the specificity of the enzyme for its substrates.

True

What carbohydrates is the precursor for making PRPP?

Ribose-S-Phosphate

When alpha-ketoglutarate transaminates, what amino acid does it become?

glutamate

True or false: nitrogen fixation does not require ATP hydrolysis.

False

What amino acid derivative is the major source of methyl groups in biochemical methylation reactions?

AdoMet

List the 3 sources of the atoms found in pyrimidine bases.

carbamoyl phosphate, aspartate, folate

In what part of the cell are steroid hormone receptors found?

cytoplasm

What enzyme releases the NH4+ from glutamate?

glutamate dehydrogenase

Loss of what enzyme activity causes Lesch-Nyhan syndrome?

HGPRT

What nucleotide allosterically inhibits the major regulatory step in pyrimidine biosynthesis?

CTP

Oncogenic forms of Ras often have a decrease in what catalytic activity?

GTPase

What enzyme activity is affected by the alpha subunits in IP3 signaling?

phospholipase C

In a general transamination reaction, an alpha amino acid (donor) donates its alpha-NH2 group to what?

alpha-ketoacid acceptor

List 3 sources for the atoms found in purine bases.

CO2, folate, aspartate

What ion signal for neurons to release acetylcholine into the synapse?

Ca2+

How many subunits does a G protein have?

3 subunits: alpha, beta, gamma

What is the end product of purine base catabolism?

uric acid

What nucelotides allosterically inhibit the first step of purine biosynthetic pathway?

ADP, AMP, GDP, GMP

What catalytic activity does the insulin receptor have?

(RTK) Tyrosine kinase

Which amino acids are soley ketogenic?

leucine and lysine

What nucleotide is the initial product of the purine biosynthetic pathway?

IMP