Bis 103 practice final 3

Proline is synthesized from Glu in a pathway that involves the following reaction:
Pyrroline 5 carboxylate + NAD(P)H + H+ ---> Proline + NAD(P)+
Which enzyme below catalyzes this reaction?

- Proline reductase
-Pyrroline 5 carboxylate dehydrogenase
- Proline isomerase
- Pyrroline 5 carboxylate reductase
- Proline phosphatase

Proline is synthesized from Glu in a pathway that involves the following reaction:
Pyrroline 5 carboxylate + NAD(P)H + H+ ---> Proline + NAD(P)+
Which enzyme below catalyzes this reaction?

- Proline reductase
-Pyrroline 5 carboxylate dehydrogenase
- Proline isomerase
- Pyrroline 5 carboxylate reductase
- Proline phosphatase

Pyrroline 5 carboxylate reductase

Which of the following statements accurately describe(s) an allosteric regulator of amino acid biosynthesis?

- Isoleucine activates an enzyme that catalyzes the first step in its biosynthesis pathway.
-. High levels of AMP (a product of Gln metabolism) decreases the activity of glutamine synthetase.
- Low levels of glycine decrease the activity of glutamine synthetase.
- Covalent attachment of an AMP to glutamine synthetase alters the enzyme's activity.
- All of the above.

High levels of AMP (a product of Gln metabolism) decreases the activity of glutamine synthetase.

What is a difference between the inner mitochondrial membrane (IMM) and the outer mitochondria membrane (OMM)?

- The OMM is not permeable to any molecules, while the IMM is permeable to some molecules.
- The OMM has more cristae than the IMM.
- The IMM contains Complexes I, II, III, and IV of the electron transport chain.
- ATP synthase is embedded in the OMM, with the catalytic sites of the enzyme facing the intermembrane space.
-Two or more of the above are differences between the OMM and IMM.

- The IMM contains Complexes I, II, III, and IV of the electron transport chain.

In the context of amino acid catabolism, which of the following cofactors plays a role in the transfer of carbon as methyl groups?

- Biotin
- Tetrahydrofolate
- S-Adenosylmethionine
- Pyridoxal phosphate
- Two or more of the above

Two or more of the above

Which of the following statements about the Urea cycle is/are true?

- The urea cycle does not require ATP hydrolysis.
- Most reactions of the urea cycle occur in the mitochondria.
- Oxaloacetate is one enzymatic step away from being an intermediate of the urea cycle.
- Urea is formed by a condensation reaction catalyzed by a synthetase.
- All the above.

Oxaloacetate is one enzymatic step away from being an intermediate of the urea cycle.

Which of the following statement(s) about flavoproteins is/are true?

-Flavoproteins catalyze oxidation and reduction reactions.
-NAD+ is associated with flavoproteins and can accept 1 or 2e−.
- Flavoproteins have a standard reduction potential of -0.314 V.
- Flavoproteins are coenzymes.
- More than one choice above is true.

Flavoproteins catalyze oxidation and reduction reactions

Which of the following molecules decreases the rate of flux through the citric acid cycle?

- Adenosine monophosphate
- Coenzyme A
- Calcium ions
- Adenosine diphosphate
- None of the above

none of the above

ATP synthase utilizes rotational catalysis to facilitate ATP synthesis. Rotational catalysis specifically refers to _____.

- the rotation of α and β subunits of the F1 domain.
- the rotation of substrates binding the active sites in the beta subunits of ATP synthase.
- the transfer of H+ across the inner mitochondrial membrane.
- the rotation of the γ subunit of the F1 domain.
- the rotation of all F0 domain proteins.

the rotation of the γ subunit of the F1 domain.

In the direction that drives of ATP synthesis, the electron transport chain (ETC) involves _____.

- Direct electron transfer from NADH to Complex II of ETC.
- Direct electron transfer from Fumarate to Complex II of ETC.
- Direct electron transfer from Complex IV to Ubiquinone.
- Complex IV of the ETC pumping H+ from P side to N side.
- None of the above.

None of the above.

Nitrogen from amino acid catabolism in skeletal muscle is primarily transported to the liver in the form of _____.

- Alanine
- Glutamate
- γ-Glutamyl phosphate
- Ammonia
- All the above

alanine

Which of the following molecules is an excretory form of nitrogen in animals?

memorize structures

Which of the following enzymes catalyzes this reaction?

glutamate dehydrogenase

You are studying an unknown toxin. You add various compounds, including the toxin, to mitochondria in buffer and record the graph below. Based on your data, which of the following is the most likely effect that this toxin has on healthy, functional mitochondria? (Note: Venturicidin is an antibiotic that inhibits ATP synthase.)

idk just look at practice test

This toxin likely dissipates the proton gradient.

Which of the following molecules can increase the activity of pyruvate kinase when it is at high enough concentration?

- Fructose 1,6-bisphosphate
- ATP
- Pyruvate
- Alanine
- Acetyl CoA

Fructose 1,6-bisphosphate

The electron transport chain in a newly identified mammal is similar to ours but has different proteins than we have. As a researcher, you want to determine the order in which these proteins pass electrons to each other. The proteins are called FE, FI, FO, and FUM. In the lab, you use an electron flow inhibitor on cells from this species and find that FO and FUM are reduced, while the rest are oxidized. You can assume the cells have a source of electrons to feed into the chain and a final electron acceptor like oxygen. Which of the following order of proteins is consistent with your data?

- FUM, FO, FE, FI
- FE, FI, FUM, FO
- FUM, FI, FE, FO
- FO, FE, FI, FUM
- None of the above

FUM, FO, FE, FI

Because of chemiosmotic coupling, ATP synthesis _______.

- is not linked to electron movement in the electron transport chain.
- is driven by the proton motive force.
- is not linked to the oxygen consumption rate.
- is dependent on the oxidation/reduction reactions that take place in ATP Synthase.
- All the above.

is driven by the proton motive force

List the following in order of increasing tendency to accept electrons: (a) Lipoic Acid; (b) Cytochrome f (Fe3+); (c) Crotonoyl-CoA ; (d) Pyruvate

C. a, d, c, b

Which of the following statements about the mitochondrial respiratory chain is/are true?

- The respiratory chain contains one type of electron carrier.
- One protein in the mitochondrial respiratory chain is not part of a protein complex.
- In the mitochondrial respiratory chain, ubiquinone is a membrane bound protein that functions as an e− carrier.
- There is one entry point for electrons that are going to travel through the chain.
- All of the above are true.

One protein in the mitochondrial respiratory chain is not part of a protein complex.

The most oxidized form of nitrogen in the nitrogen cycle is _____.

- N2
- NO3−
- NO2−
- NH4+
- More than one choice above.

NO3−

You know that to build muscle you need to eat enough protein, as the amino acids in ingested protein can be building blocks for muscle protein. You want to build muscle but you also don't want to waste money by eating more protein than you actually use. Measuring which of the following can help you decide whether or not you are eating too much protein?

- the amount of alanine in your urine
- the amount of urea in your urine
- the amount of ketones in your blood
- the amount of free fatty acids in your blood
- the amount of acetone in your breath

the amount of urea in your urine

Flux through a metabolic pathway can be regulated by _____.

- extracellular signals (e.g. neurotransmitters and hormones)
- the presence of regulatory proteins.
- controlling the degradation of enzymes.
- covalent modification of enzymes.
- All the above

all of the above

Which of the following changes are likely to happen shortly after you have a meal?

- decrease in glycogen phosphorylase activity
- decrease in phosphofructokinase 1 activity
- increase in PEP (phosphoenolpyruvate) carboxykinase
- increase in glucagon concentration in the bloodstream
- all of the above

decrease in glycogen phosphorylase activity

Muscle hexokinase has a lower Km (i.e. substrate concentration at ½ saturation) than liver hexokinase because ________.

- the muscle only consumes glucose for anaerobic respiration.
- the muscle needs to maintain blood glucose levels.
- the muscle needs to lower glucose use in response to high blood glucose level after a meal.
- muscle hexokinase is not inhibited by glucose-6-phosphate.
- glucose does not need to leave the muscle cell.

glucose does not need to leave the muscle cell.

The liver plays a central role in mammalian metabolism. Which of the following statements is false about how sugars, amino acids, and fatty acids are metabolized in the liver?

- Fatty acids in a liver cell can be used to produce lipids for the cell to incorporate into its membranes.
- Fatty acids can be oxidized completely in the liver to supply energy for the liver cells.
- Through fermentation, glucose can be converted to lactate in the liver and used in gluconeogenesis.
- Amino acids can be used for protein synthesis or for producing fuel that can be exported to other tissues.
- Unlike sugar and fatty acids, there is no storage form of amino acids in the liver that has the sole purpose of providing energy when needed.

Through fermentation, glucose can be converted to lactate in the liver and used in gluconeogenesis.

Based on the information provided below, what is the ΔG'° for the spontaneous electron transfer between Pyruvate and Ethanol?

Pyruvate− + 2H+ + 2e− → lactate− E'° = −0.185 V
Acetaldehyde + 2H+ + 2e− → ethanol E'° = −0.197 V

Faraday constant = 96.5 kJ V-1 mol-1

-2.316 kj/mol

Inhibiting which of the following enzymes hinders the breakdown of leucine in extrahepatic tissues?

- Leucine aminotransferase
- Leucine dehydrogenase complex
- Branched-chain alpha keto acid dehydrogenase complex
- Coenzyme A
- All of the above

Branched-chain alpha keto acid dehydrogenase complex

What role does the blood play in metabolism? The blood _____.

- moves energy-rich molecules between various organs.
- participates in metabolic regulation by transporting insulin and glucagon.
- is critical for the metabolic cooperation between skeletal muscle and liver.
- is critical for generating the metabolic effects of prolonged fasting.
- All the above.

all of the above

N-acetylglutamate, at high enough concentration, can ______.

- increase flux through the urea cycle by increasing the activity of N-acetylglutamate synthase.
- increase flux through the urea cycle by allosterically regulating arginase.
- increase flux through the urea cycle by decreasing the activity of carbamoyl phosphate synthetase I.
- increase flux through the urea cycle by increasing the activity of carbamoyl phosphate synthetase I.
- not effect the urea cycle.

increase flux through the urea cycle by increasing the activity of carbamoyl phosphate synthetase I.

Glucogenic amino acids can be broken down to form

- Leucine
- Acetyl-CoA
- Fumarate
- Acetoacetyl-CoA
- All the above

Fumarate

A spider toxin that inhibits gluconeogenesis but does not affect glycolysis may be allosterically regulating which of the enzymes below?

- Phosphohexose isomerase
- Pyruvate kinase
- Pyruvate carboxylase
- Enolase
- Two or more of the above

Pyruvate carboxylase

Inhibition of phosphate translocase will most likely lead to _____.

- a depletion of inorganic phosphate in the mitochondrial matrix.
- an increase in ATP synthesis.
- the dissipation of the proton gradient across the inner mitochondrial membrane.
- an increase in oxygen consumption rate.
- all of the above.

a depletion of inorganic phosphate in the mitochondrial matrix.

Which of the following statements about the glucogenic mammalian liver is/are true?

- A hormone increases glycogen breakdown by upregulating glycogen synthase.
- A hormone increases glycolysis by downregulating phosphoglucokinase 1.
- A hormone decreases fatty acid synthesis by downregulating acetyl-CoA carboxylase.
= A hormone decreases glycogen breakdown by decreasing glycogen phosphorylase.
- All of the above.

A hormone decreases fatty acid synthesis by downregulating acetyl-CoA carboxylase.

What can the brain use to generate energy?

- Glucose from the metabolism of glycerol in triglycerides.
- β-hydroxybutyrate from the breakdown of fatty acids in the brain.
- Pyruvate from gluconeogenesis in the brain.
-Ketone bodies from gluconeogenesis.
- Creatine.

Glucose from the metabolism of glycerol in triglycerides.