Lecture 9- Cellular Respiration

Question 1

What are the four main stages of cellular respiration in order?

Answer 1

Glycolysis → pyruvate oxidation → citric acid cycle → oxidative phosphorylation

Question 2

What is the source of electrons for cellular respiration?

Answer 2

Glucose

Question 3

What are the reactants and products of pyruvate oxidation?

Answer 3

Pyruvate → Acetyl-CoA

Question 4

Where does glycolysis take place?

Answer 4

Cytosol

Question 5

The initiation of the citric acid cycle is marked by the reaction between ______ and ______.

Answer 5

Oxaloacetate and Acetyl-CoA

Question 6

Where does the citric acid cycle take place?

Answer 6

Mitochondrial matrix

Question 7

Which substances undergo redox during cellular respiration?

Answer 7

Glucose is oxidized and oxygen is reduced

Question 8

Where does oxidative phosphorylation take place?

Answer 8

Mitochondrial cristae

Question 9

Is cellular respiration an endergonic or exergonic process? Is the change in Gibbs free energy negative or positive?

Answer 9

Exergonic process → negative change in Gibbs free energy

Question 10

Oxidative phosphorylation is composed of two major stages. What are these stages?

Answer 10

Electron transport chain (ETC) & chemiosmosis

Question 11

How does glucose enter mammalian cells?

Answer 11

Facilitated diffusion via GLUT1

Question 12

True or false: Two ATP are generated during pyruvate oxidation

Answer 12

False; ATP is not used or made during pyruvate oxidation

Question 13

True or false: For every one glucose molecule, there is one cycle of the citric acid cycle

Answer 13

False; there are two cycles of the citric acid cycle for every one glucose molecule

Question 14

What are the two main stages of glycolysis?

Answer 14

Investment phase → payoff phase

Question 15

How many ATP are produced via oxidative phosphorylation?

Answer 15

Approximately 28

Question 16

The conversion of glucose to glucose-6-phosphate is catalyzed by _____.

Answer 16

Hexokinase

Question 17

True or false: In the absence of oxygen, glucose will proceed to pyruvate oxidation indefinitely

Answer 17

False; pyruvate oxidation may be able to occur for a short period in the absence of oxygen, but not for extended periods of time

Question 18

At the end of glycolysis, where are the electrons from the initial glucose?

Answer 18

Pyruvate and NADH

Question 19

In which molecule is energy stored during the citric acid cycle?

Answer 19

NADH

Question 20

What are the gross products of glycolysis?

Answer 20

4 ATP + 2 NADH + 2 Pyruvate

Question 21

What are the net products of glycolysis?

Answer 21

2 ATP + 2 NADH + 2 Pyruvate

Question 22

At the end of pyruvate oxidation, where are the electrons?

Answer 22

Acetyl-CoA and NADH

Question 23

True or false: Glycolysis is an anaerobic process

Answer 23

TRUE

Question 24

True or false: Upon entry to a cell, glucose will remain as glucose until it is needed by the organelles

Answer 24

False; glucose is split immediately after entering the cytosol

Question 25

Which metabolic process will pyruvate undergo in the absence of oxygen?

Answer 25

Fermentation

Question 26

What occurs during pyruvate oxidation?

Answer 26

Catalyzed by pyruvate dehydrogenase, a carboxyl group is removed from pyruvate, releasing carbon dioxide → NAD+ reduced to NADH

Question 27

What is the first metabolite of glycolysis?

Answer 27

Glucose-6-phosphate

Question 28

Why is the first phase of glycolysis considered an investment?

Answer 28

Two ATP are needed to facilitate conversion of glucose to glyceraldehyde-3-phosphate (G3P)

Question 29

True or false: The investment phase of glycolysis is an exergonic process

Answer 29

False; the investment phase of glycolysis is an endergonic process