Cellular Respiration

Question 1

How is ATP generated? (2 ways)

Answer 1

1. substrate-level phosphorylation
2. oxidative phosphorylation

Question 2

Substrate-level phosphorylation

Answer 2

An organic molecule transfers a phosphate group directly to ADP to make ATP. Includes a hydrolysis reaction to yield a phosphate group, and a reaction to couple that phosphate group to ADP.

Only produces a small amount of fuel.

Question 3

Oxidative phosphorylation

Answer 3

1. Chemical energy from org molecule transferred to electron carriers (electron transport chain)
2. Energy gathers as electron moves through ETC, releasing to produce ATP

Question 4

Two electron carriers:

Answer 4

NAD and FAD

Question 5

Oxidized form of NAD and FAD

Answer 5

NAD+ and FAD

Question 6

Reduced form of NAD and FAD

Answer 6

NADH and FADH2

Question 7

Reduced molecules experience an increase in what type of bond?

Answer 7

C-H

Question 8

What are the four stages of cellular respiration?

Answer 8

1. Glycolysis
2. Pyruvate Oxidation
3. Citric acid cycle
4. Oxidative phosphorylation

Question 9

What happens during glycolysis?

Answer 9

Glucose partially broken down to produce pyruvate.

Energy transferred to ATP and reduced e- carriers.

Question 10

What happens in Pyruvate Oxidation?

Answer 10

Pyruvate oxidized to make acetyl-CoA.

This produces reduced e- carriers and CO2 is released.

Question 11

What happens during the citric acid cycle?

Answer 11

Acetyl-CoA enters.

Acetyl group oxidized to CO2.

Energy is transferred to ATP and reduced electron carriers.

Question 12

What happens during oxidative phosphorylation?

Answer 12

The reduced e- carriers generation from stages 1, 2, and 3 donate e- to the respiratory electron transport chain. LOTS of ATP produced!

Question 13

What are the three phases of glycolysis?

Answer 13

1. Preparatory phase (uses 2 ATP)
2. Cleavage phase
3. Payoff phase (produces 4 ATP + 2 NADH)

Question 14

Phases of Glycolysis

Answer 14

1. Addition of two phosphate groups. Requires 2 ATP = phosphorylated glucose. This step destabilizes and traps the molecule.
2. Cleavage. Split from 6C molecule to two 3 C molecules. [G3P]
3. Payoff. ATP and NADH produced as well as 2 molecules pyruvate.

Question 15

What are the products of glycolysis?

Answer 15

2 pyruvate
4 ATP (but 2 consumed)
2 NADH

Question 16

What are the reactants of glycolysis?

Answer 16

Single molecule of glucose.

Question 17

Pyruvate Oxidation

Answer 17

Pyruvate oxidized to acetyl-CoA, enters citric acid cycle.

Question 18

Intermembrane space

Answer 18

Space between the inner and outer membranes.

Question 19

Mitochondrial Matrix

Answer 19

Space enclosed by the inner membrane.

Question 20

How is pyruvate oxidation initiated?

Answer 20

Pyruvate enters the mitochondrial matrix, converted to acetyl-CoA.

Question 21

How is pyruvate converted to acetyl-CoA?

Answer 21

Pyruvate is oxidized, forms CO2.

Electrons go to NAD+, turns into NADH.

Remaining part of pyruvate (COCH3) transferred to CoA.

Question 22

What are the products of pyruvate oxidation?

Answer 22

1 CO2
1 NADH

PER pyruvate. 2 enter so products x2

Question 23

What substrate enters the citric acid cycle?

Answer 23

Acetyl-CoA

Question 24

Summarize the citric acid cycle

Answer 24

Acetyl group of acetyl-CoA is oxidized to CO2. Chemical energy is transferred to ATP and to the reduced e- carriers NADH and FADH2.

**Supplies electrons to the electron transport chain*

Question 25

What does the citric acid cycle produce?

Answer 25

ATP and reduced electron carriers NADH and FADH2.

Question 26

Where does the citric acid cycle take place?

Answer 26

Mitochondrial matrix

Question 27

Where does the synthesis of acetyl-CoA take place?

Answer 27

Mitochondrial matrix

Question 28

Steps of the citric acid cycle

Answer 28

1. Acety-CoA turned into citric acid.
2. Citric acid oxidized through a series of reactions.
3. Redox reactions occur to produce reduced e- carriers that donate e- to the ETC.

Question 29

Overall citric acid cycle produces:

Answer 29

2 acetyl-CoA produced from a single molecule of glucose yield

2 ATP
6 NADH
2 FADH2

Question 30

Summary of oxidative phosphorylation

Answer 30

Reduced e- carriers donate e- to the ETC, leading to ATP synthesis. H2O is a biproduct.