4.2-4.3 Glycolysis and Fermentation/ Aerobic Respiration

In the Krebs cycle, _______ ATP, ______ NADH + H +, and ______ FADH2 are produced for every one molecule of glucose that was broken down in glycolysis.

2, 6, 2

How many ATP molecules are synthesized directly in the Kreb's cycle if you supply an aerobic cell with 10 glucose molecules?

20

Acetyl CoA is a ____-carbon molecule that combines with oxaloacetate, a ____-carbon molecule to form citrate, a ____-carbon molecule.

2; 4; 6

How many ATP are produced directly from glycolysis and the Krebs cycle for each glucose molecule that enters glycolysis?

4

If 25 micromoles of acetyl CoA enter the Krebs cycle, how many micromoles of NADH will be produced?

75

Which of the following statements regarding the acetyl CoA step is false? -Pyruvate dehydrogenase is an enzyme complex that is attached to the inner mitochondrial membrane. -Pyruvate is oxidized to form acetate during the acetyl CoA step. -During the acetyl CoA step, carbon dioxide is added to pyruvate. -NAD+ is reduced as pyruvate is converted to acetyl CoA.

During the acetyl CoA step, carbon dioxide is added to pyruvate.

For each pyruvate that is formed in glycolysis, how many carbon dioxide molecules are released from the Krebs cycle?

2

Glycolysis is an ________ process in which glucose undergoes _________.

Anaerobic; oxidation

Which of the given molecules serves as an electron acceptor in the Krebs cycle? --FAD --citrate --NADH --CO2

FAD

Which of the following molecules are not formed during glycolysis? -ATP -FADH2 -NADH -Pyruvate

FADH2

True or false? The acetyl CoA step is the first step in the Krebs cycle.

False.

Fermentation

Fermentation does not require oxygen. Fermentation is actually a mechanism for ATP production in the absence of oxygen. Fermentation oxidizes NADPH + H+ to form NAD+, which is necessary for glycolysis to take place. By recycling NAD+ in fermentation, the cell is able to exist on the ATP provided by glycolysis alone in the absence of oxygen.

Comparing glycolysis under anaerobic conditions to glycolysis under aerobic conditions, which statement is true? --Humans are capable only of aerobic respiration. --Pyruvate is converted to lactate under aerobic conditions, while it is converted to acetyl CoA under anaerobic conditions. --Glycolysis occurs under aerobic conditions, while fermentation occurs under anaerobic conditions. --Glucose is converted to pyruvate and then lactate under anaerobic conditions, while it is converted to acetyl CoA under aerobic conditions.

Glucose is converted to pyruvate and then lactate under anaerobic conditions, while it is converted to acetyl CoA under aerobic conditions.

The pathway in which glucose is broken down to form pyruvate is called

Glycolysis

During two steps in glycolysis, ATP is hydrolyzed in order to form phosphorylated intermediates. Which two enzymes mediate these respective reactions?

Hexokinase; Phosphofructokinase

Which statement regarding fermentation is true?

In alchohol fermentation, pyruvate is first converted to acetaldehyde in a decarboxylation reaction and then converted to ethanol, forming NAD+

Which statement regarding the isomerase enzyme in the first half of glycolysis is true? -Isomerase catalyzes a one-way reaction. -Isomerase interconverts glyceraldehyde-3-phosphate to dihydroxyacetone phosphate, and vice versa. -Isomerase converts fructose-6-phosphate to fructose-1,6-biphosphate. -Isomerase is not an enzyme that functions in the first half of glycolysis.

Isomerase interconverts glyceraldehyde-3-phosphate to dihydroxyacetone phosphate, and vice versa

Which statement about pyruvate is false? --It is a peptide. --It is the product of glycolysis. --It is a three-carbon molecule. --It is reduced during fermentation

It is a peptide.

Which of the following statements is true regarding fermentation? -It is done only in prokaryotic cells. -It produces a NAD+ -It produces two additional ATP. -It recycles glucose.

It produces a NAD+

Two important electron acceptors in aerobic cellular respiration are:

NAD+ and FAD

Fermentation enables

NADH + H+ to be oxidized to form NAD+ so that glycolysis will continue.

The acetyl CoA step produces

NADH + H+, and CO2

Which of the following is not a product of respiration up to the Krebs cycle (from glycolysis to the Krebs cycle): --NADPH + H+ --CO2 --FADH2 --ATP

NADPH + H+

An important principle of fermentation is that

O2 is not used as a final electron acceptor.

Acetyl CoA enters the Krebs cycle by combining with:

Oxaloacetate

Which of these statements is false regarding pyruvate? --Pyruvate is formed from the splitting and oxidation of glucose. --Pyruvate is converted to acetyl CoA and then transfered to the mitochondrial membrane where it will enter into the Kreb's cycle. --Pyruvate occupies a key position as a branching point in chemotrophic energy metabolism. --Pyruvate is composed only of carbon hydrogen and oxygen.

Pyruvate is converted to acetyl CoA and then transfered to the mitochondrial membrane where it will enter into the Kreb's cycle.

transfers a phosphate group from PEP to form ATP

Pyruvate kinase

All of the statements concerning cellular respiration are true except: --In the Krebs cycle, two molecules of carbon dioxide and one molecule of FADH2 are produced for each acetyl CoA that enters the cycle. --The metabolic breakdown of glucose yields more energy during fermentation than during aerobic respiration. --The conversion of glucose to pyruvate can occur in the absence of oxygen. --When aerobes respire anaerobically, they may build up an oxygen debt that may be paid eventually with the intake of oxygen.

The metabolic breakdown of glucose yields more energy during fermentation than during aerobic respiration.

The role of hexokinase in the first part of glycolysis is:

The phosphorylation of glucose

True or false? Glycolysis yields more ATP than fermentation alone

True.

Which of the following molecules is reduced during alcohol fermentation? -NAD+ -ethanol -acetaldehyde -pyruvate

acetaldehyde

Glycolysis begins in the __________ and ends in the _____________.

cytoplasm; cytoplasm

Glycolysis takes place in the ________, fermentation takes place in the ________, and the Krebs cycle takes place in the ________.

cytosol; cytosol; matrix

Fermentation differs from cellular respiration because

fermentation does not require oxygen.

A major function of the citric acid cycle is to

generate stored energy in the form of NADH + H+

During glycolysis

glucose is broken down and oxidized to form two pyruvate molecules, a net of two ATP, and two NADH.

One round of glycolysis

involves the use of kinase enzymes to synthesize ATP.

Pyruvate is converted to acetyl CoA in the

mitochondria.

An important goal of the energy investment phase of glycolysis is the

phosphorylation of a 6-carbon molecule

Glycolysis accounts for all of the following except -production of H2O -production of pyruvic acid -production of ATP -production of NADH

production of pyruvic acid

What is the electron acceptor during lactic acid fermentation?

pyruvate

In the energy investment phase of glycolysis

two molecules of ATP are invested making glucose and its derivatives more reactive.

The acetyl CoA step in cellular respiration takes place

under aerobic conditions.