Chapter 9

Question 1

Difference between fermentation and aerobic respiration

Answer 1

Fermentation - partial degradation of sugars or other organic fuel that occurs without the use of oxygen
Aerobic - consumed oxygen as a reactant along with organic fuels

Question 2

Reactants of cellular respiration

Answer 2

Glucose and oxygen

C6H12O6 + 6 O2

Question 3

Products of cellular respiration

Answer 3

Carbon dioxide, water, and energy

6 CO2 + 6 H2O + Energy

Question 4

Difference between oxidation and reduction

Answer 4

Oxidation is loss of electrons
Reduction is addition of electrons
OIL
RIG

Question 5

When compounds lose electrons, they __ energy; when compounds gain electrons, they __ energy

Answer 5

Require

Release

Question 6

In cellular respiration, electrons are not transferred directly from glucose to oxygen. Following the movement of hydrogen’s allows you to follow the flow of electrons. What electron carrier is hydrogen transferred to first?

Answer 6

NAD +

It is a coenzyme

Question 7

What are coenzymes?

Answer 7

An organic cofactor

Question 8

Describe what happens when NAD + is reduced. What enzyme type is involved?

Answer 8

NADH

Question 9

What is the function of the electron transport chain in cellular respiration?

Answer 9

A sequence of electron carrier molecules (membrane protein) that shuttles electrons

Question 10

Electron transport involves a series of electron carriers
Where are these found in eukaryotic cells?
Where are these found in prokaryotic cells?

Answer 10

Inner mitochondrion membrane

Plasma membrane

Question 11

What strongly electronegative atom, pulling electrons down the electron transport chain, is the final electron acceptor?

Answer 11

Oxygen

Question 12

Explain how the electron transport chain utilized in oxidative phosphorylation

Answer 12

The steps of the electron transport chain releases energy. This energy is used to phosphorylate (add a phosphate to) ADP to synthesize ATP

Question 13

What is the meaning of glycolysis? What occurs in this step of cellular respiration?

Answer 13

Behind the degradation process by breaking glucose into 2 molecules of a compound (pyruvate)
Sugar splitting

Question 14

Where does glycolysis occur in the cell? Is oxygen required?

Answer 14

Glycolysis occurs in the cytoplasm, whether or not oxygen is present

Question 15

Three steps of the citric acid cycle

Answer 15

The carbonyl group is removed from pyruvate, forming CO2
Electrons are transferred to NAD+, forming NADH
Coenzyme A is attached to carbon fragment, creating a very restive chemical: acetyl coA

Question 16

Citric Acid Cycle:
How may NADHs are formed?
How many total carbons are lost as pyruvate is oxidized?
The carbons are lost in which molecule?
How many FADH2 are formed?
How many ATPs are formed?
How many times does the citric acid cycle occur for each molecule of glucose?

Answer 16

3
2
CO2
1
1
Twice

Question 17

Explain what happened (in the citric acid cycle) to each of the six carbons found in the original glucose molecule

Answer 17

Each carbon has been released as CO2

6 CO2

Question 18

Why is oxygen considered the ultimate electron acceptor?

Answer 18

Oxygen is very electronegative and readily accepts electrons
-pulls electrons towards it

Question 19

Oxygen stabilizes the electrons by combining with two hydrogen ions to form what?

Answer 19

Water

Question 20

What are the two electron carrier molecules that feed into the electron transport system?

Answer 20

NADH & FADH2

Question 21

Explain the overall concept of how ATP synthase uses the flow of hydrogen ions to produce ATP

Answer 21

The flow of H+ ions down their gradient causes the protein synthase to rotate. This rotation activates catalytic sites on the matrix side of the protein to produce ATP from ADP and P

Question 22

What is the role of the electron transport chain in forming the H+ gradient across he inner mitochondrial membrane?

Answer 22

The electron transport chain uses exergonic flow of electrons from NADH & FAFH2 to pump H+ ions across the membrane from the mitochondrial matrix into the intermembrane soace. This forms an H+ gradient

Question 23

Relate chemiosmosis and proton-notice force to the process of oxidative phosphorylation

Answer 23

The electron transport chain created an increase an potential energy as it creates the H+ ion gradient. This potential energy creates proton-motive force that allows chemiosmosis to occur. The H+ ions flow down that gradient through ATP synthase, driving the synthesis of ATP

Question 24

Fermentation allows for the production of ATP without using either __ or any __

Answer 24

Oxygen

Electron transport chain

Question 25

Alcohol fermentation starts with glucose and yields ethanol. Explain this process

Answer 25

Glucose is broken down to pyruvate, 2 NAD+ are reduced to 2 NADH. In order to recycle the NAD+ to generate more ADP from glucose, pyruvate is converted to acetaldehyde. Acetaldehyde is then reduced to ethanol, gaining electrons from 2 NADH. This oxidizes 2 NADH back to NAD+ so that glycolysis can continue

Question 26

Lactic acid fermentation starts with glucose and yields lactate. Explain this process

Answer 26

As glucose is broken down to pyruvate, 2 NAD+ are reduced to 2 NADH, generating a net of 2 ATP. In order to continue the breakdown of more glucose molecules, pyruvate is reduced to lactic acid by gaining electrons from 2 NADH. This oxidized 2 NADH back to 2 NAD+ so that it can be reused in glycolysis

Question 27

What three organic macromolecules are often utilized to make ATP by cellular respiration?

Answer 27

Proteins, carbohydrates, fats

Question 28

Explain the difference in energy usage between the catabolic reactions of cellular respiration and the anabolic pathways of biosynthesis

Answer 28

In cellular respiration, energy is used to synthesize ATP

In biosynthesis, energy is used from ATP to synthesize more complex molecules