Chapter 7: Cellular Respiration

Question 1

What is Cellular Respiration?

Answer 1

A series of catabolic reactions that uses chemical energy to produce ATP

Question 2

What is the difference between “Aerobic” and “Anaerobic” Respiration?

Answer 2

Aerobic Respiration:
WITH oxygen
(C6H1206 + CO2 ->
6CO2 + 6H20 + Energy!)

Anaerobic Respiration:
WITHOUT oxygen

Question 3

What is the difference between “Oxidation” and “Reduction”?

Answer 3

O.I.L.
R.I.G.

Oxidation Is Losing electrons
(loss of energy)

Reduction Is Gaining electrons
(gain of energy)

Question 4

In cellular respiration, what is being oxidized and what is being reduced?

Answer 4

Glucose is oxidized (loses electrons to become CO2)

Oxygen is reduced (gains electrons to become water)

Question 5

What are the 4 stages of Cellular Respiration and where do they occur?

Answer 5

1) Glycolysis
- Cytoplasm
2) Acetyl-CoA Synthesis
- Mitochondrial Matrix
3) Citric Acid
- Mitochondrial Matrix
4) Oxidative Phosphorylation
- Intermembrane Space of Mitochondria

Question 6

Is Glycolysis an “Endergonic” or “Exergonic” process? What are the reactants and products?

Answer 6

Glycolysis is Exergonic: even though a little bit of energy is required to break down glucose and to perform “Pyruvate Oxidation”, energy is RELEASED in the form of ATP and NADH.

1 Glucose Molecule + 2 ATP =
-> 4 ATP (2 Net ATP)
-> 2 NADH (electron carriers)
-> 2 Pyruvate (used later in Acetyl-CoA Synthesis)

Question 7

What are the reactants and products of Acetyl-CoA Synthesis?

Answer 7

2 Pyruvate =
-> 2 Acetyl-CoA Molecules
-> 2 NADH (electron carriers)
-> 2 CO2 Molecules (1 per Pyruvate)

Question 8

What are the reactants and products of the Citric Acid Cycle?

Answer 8

(A.K.A. Krebs Cycle)

2 Acetyl-CoA Molecules +H2O =
-> 6 NADH
-> 2FADH2
-> 4CO2
-> 2 ATP

• Although modest amounts of ATP is created, most energy is stored in these electron carriers until Oxidative Phosphorylation

Question 9

What happens during Oxidative Phosphorylation? What are the products?

Answer 9

(A.K.A. Electron Transport Chain)

The ETC takes electrons from electron carriers (NADH and FADH2) and runs them through several complexes I and II.

Meanwhile, protons (hydrogen ions) are being pumped into the membrane creating a positive gradient inside the membrane.

ATP Synthase is then able to use this gradient to create ATP and oxygen is reduced to become water

10 NADH + 2 FADH2 +O2 =
-> 28-32 ATP
-> H2O

Question 10

How much energy in the form of ATP can be produced with just 1 molecule of glucose through cellular respiration?

Answer 10

Usually 32-36 ATP

Question 11

How is glucose stored in animals and in plants?

Answer 11

Animals: Glycogen
Plants: Starch

Question 12

What is “Fermentation”? Where does this happen? What are the results of fermentation?

Answer 12

Fermentation is an anaerobic process in which energy can be released from glucose even though oxygen is not available.

Fermentation occurs in yeast cells, and a form of fermentation takes place in bacteria and in the muscle cells of animals.

Allows glycolysis to restart and produces “Lactic Acid”

• Fermentation is important for adding new flavors and textures to food, extending the shelf life of foods, making some nutrients more easily absorbed by the body, and providing an environment for probiotics to grow and reproduce.