Quiz 4 bch

Which of the following represents the net products of glycolysis from one molecule of glucose?

2 pyruvate, 2 NADH, 2 ATP

What enzyme catalyzes the major regulatory step of glycolysis?

phosphofructokinase

Which of the following contains a high energy bond that is used for a substrate level phosphorylation in glycolysis?

1,3-bisphosphoglycerate

What is the most important regulatory enzyme of glycolysis that is bypassed during fructose metabolism in the liver?

phosphofructokinase

Which of the following can serve as a source of carbon for gluconeogenesis?

A) glycerol B) lactate C) alanine D) glutamate E) all of the above

How many equivalents of ATP are required to convert two molecules of pyruvate to glucose?

6

Fructose-2,6-bisphosphate is an activator of _____ and an inhibitor of _____.

phosphofructokinase; fructose bisphosphatase

Gluconeogenesis is most active in the _____.

liver

What cellular location contains pyruvate dehydrogenase and most of the citric acid cycle enzymes?

mitochondrial matrix

Which of the following is an inhibitor of pyruvate dehydrogenase?

NADH

In the citric acid cycle, which of the following represents the products from the oxidation of one molecule of acetyl CoA?

2 CO2, 3 NADH, and 1 FADH2

Which enzyme catalyzes a reaction most similar to that catalyzed by pyruvate dehydrogenase?

isocitrate dehydrogenase

Which of the following is an equilibrium-controlled step within the mitochondria?

malate dehydrogenase

The oxidation of succinate to fumarate, both of which contain four carbon atoms, is best characterized as an oxidation of _____ and is unique in the CAC because it uses _____ as a coenzyme.

an alkane to an alkene; FAD

Fill in the three blanks below with the molecule that would be seen under anaerobic conditions in a yeast cell to enable glycolysis to continue.

ethanol, acetaldehyde, CO2

PDH kinase- give an activator and how it would impact the activity of PDH

ATP or NADH or AcCoA; inhibits PDH

PDH phosphatase- give an activator and how it would impact the activity of PDH

Ca2+ or low levels of ATP; activates PDH

Where does glycolysis take place?
Group of answer choices

cytosol

What is the main purpose of phosphorylating glucose in the first step of glycolysis?

to prevent the molecule from leaving the cell

In the liver, phosphofructokinase-1 is likely to be ------- after a long period of starvation, as the molecule ------- is present in the blood stream.

Inhibited; glucagon

The investment phase of glycolysis (the first half of glycolysis) requires an input of ---- ATP, while the pay-off phase (the second half of glycolysis) produces ----- ATP. This gives an overall net production of -------- ATP from glycolysis

2, 4, 2

Which of the following best describes substrate level phosphorylation?

production of ATP from the transfer of a phosphate (Pi) group from a phosphorylated compound to ADP

Erythrocytes (red blood cells) with a deficiency in pyruvate kinase are not able to function effectively because _____.

red blood cells do not have mitochondria, and therefore rely on glycolysis for all energy production

Glycolysis is important because it _____.

provides some energy but also provides other pathways with a molecule that is easily oxidized

The products of glycolysis from one molecule of glucose are [ Select ] pyruvate, [ Select ] ATP, and [ Select ] NADH.

2, 2, 2

Which of the following enzymes requires ATP as a substrate?

phosphofructokinase

Phosphofructokinase

The enzyme that catalyzes the phosphorylation of fructose-6-phosphate to form fructose-1-6-bisphosphate in the third step of glycolysis. This is the main regulatory step of glycolysis. PFK is feedback-inhibited by ATP.

In the liver, phosphofructokinase is activated by [ Select ] which is produced by the enzyme [ Select ] in response to the hormone [ Select ] .

fructose-2,6-bisphosphate, phosphofructokinase-2, insulin

Glyceraldehyde-3-phosphate dehydrogenase oxidizes _____.

an aldehyde to a carboxylic acid

What sort of activity does fructose-1,6-bisphosphate have on pyruvate kinase?

feed-forward activator

Glyceraldehyde-3-phosphate is oxidized to [ Select ] which can transfer a phosphate to [ Select ] .

1.3-bisphosphoglycerate, ADP

Which of the following contains a high energy bond that is used for a substrate-level phosphorylation in glycolysis?

phosphoenolpyruvate

What is the impact on glycolysis in the red blood cells when high levels of arsenate are seen?

the net production of ATP would be close to 0

Under anaerobic conditions in the muscle, the net result of glycolysis is [ Select ] , [ Select ] , and [ Select ] .

2 lactate, 2 ATP, 0 NADH

While muscle is at rest, the energy charge (ratio of ATP/AMP) is [ Select ] . This results in the [ Select ] of phosphofructokinase and pyruvate kinase. During muscle activity, the energy charge is [ Select ] and [ Select ] phosphofructokinase.

High, inhibition, low, AMP activates

Under aerobic conditions, pyruvate is first [ Select ] to [ Select ] by pyruvate dehydrogenase. Under anaerobic conditions in the muscle, pyruvate is [ Select ] to [ Select ] . Under anaerobic conditions in a yeast, pyruvate is decarboxylated to [ Select

Oxidized, Acetyl CoA, Reduced, Lactate, Acetaldehyde, reduced, Ethanol

The enzymes of glycolysis that catalyze reactions with highly negative ?G values are ____, ____, and ____.

Hexokinase, Phosphofructokinase, Pyruvate kinase

The following shows the activity of PFK in the presence of low and high concentrations of ATP. Since ATP is a substrate of PFK, which of the following explain how high levels of ATP lower the activity of the enzyme. Choose all statements that are correct.

the substrate site must have a relatively low Km for ATP such that activity of the enzyme can occur even when ATP is present at low concentrations,
the regulatory site must have a fairly high Kd (dissociation constant where a high Kd means that a relative