Aerobic Respiration

Question 1

What is the starting material for glycolysis?

Answer 1

Glucose

Glycolysis begins with glucose as its primary substrate.

Question 2

What are the products of glycolysis?

Answer 2

2 NADH, 2 ATP (net), 2 pyruvate

Glycolysis produces these molecules as it converts glucose.

Question 3

Where does glycolysis take place?

Answer 3

Cytoplasm

Glycolysis occurs in the cytoplasmic fluid of the cell.

Question 4

Is oxygen required for glycolysis?

Answer 4

NO

Glycolysis is an anaerobic process.

Question 5

Why is glycolysis considered fundamental?

Answer 5

All living organisms use glycolysis, evolved very early, and is an anaerobic pathway

It predates the availability of oxygen in the atmosphere.

Question 6

What is a limitation of glycolysis?

Answer 6

Requires a continuous supply of NAD+

Without NAD+, glycolysis cannot proceed.

Question 7

What is the first solution for regenerating NAD+ in glycolysis?

Answer 7

Fermentation

Fermentation occurs in the absence of oxygen to regenerate NAD+.

Question 8

What is the process of lactate fermentation?

Answer 8

Pyruvate is reduced, and NADH is oxidized

The reaction is: Pyruvate + NADH + H+ → Lactate + NAD+.

Question 9

What happens during alcoholic fermentation?

Answer 9

Pyruvate is converted into Acetaldehyde and Carbon Dioxide

Acetaldehyde is then reduced to Ethanol.

Question 10

What is the problem at the end of glycolysis?

Answer 10

More than 90% of the energy in glucose is still trapped in reduced organic molecules

Products include pyruvate, lactate, and ethanol.

Question 11

What is the second solution for regenerating NAD+?

Answer 11

Aerobic Respiration

This occurs in the presence of oxygen.

Question 12

Where does aerobic respiration occur?

Answer 12

Mitochondrial matrix

Aerobic respiration takes place within the mitochondria.

Question 13

What does aerobic respiration consume and release?

Answer 13

Consumes Oxygen and releases CO2 and H2O

This process generates ATP from nutrients.

Question 14

How does pyruvate enter the mitochondrial matrix?

Answer 14

Passively via Porin and actively via a H+-Pyruvate cotransporter

This involves both passive and active transport mechanisms.

Question 15

What enzyme is involved in the decarboxylation of pyruvate?

Answer 15

Pyruvate Dehydrogenase

This step is crucial for converting pyruvate into Acetyl-CoA.

Question 16

What is Acetyl-CoA?

Answer 16

An important intermediate molecule in carbohydrate and fatty acid metabolism

It is produced from the breakdown of pyruvate.

Question 17

What are the products of Acetyl-CoA production from one glucose molecule?

Answer 17

2 NADH, 2 CO2, 2 Acetyl-CoA

This occurs in the mitochondria and requires oxygen.

Question 18

What occurs during the Citric Acid Cycle?

Answer 18

Produces ATP and captures high-energy electron carriers

It utilizes Acetyl-CoA as a reactant.

Question 19

How many NADH are produced in the Krebs Cycle from one glucose molecule?

Answer 19

6 NADH

This is in addition to other products like FADH2 and CO2.

Question 20

What is the role of the Electron Transport Chain?

Answer 20

Enables extensive ATP production

It is located in the inner mitochondrial membrane.

Question 21

What serves as the final electron acceptor in the Electron Transport Chain?

Answer 21

Oxygen

Oxygen combines with low-energy electrons and H+ ions to form water.

Question 22

How much ATP can be produced from each NADH and FADH2?

Answer 22

Each NADH makes ~3 ATP and each FADH2 makes ~2 ATP

This contributes to the overall ATP yield from glucose.

Question 23

What is the maximum total ATP yield from one glucose molecule?

Answer 23

34 ATP

This includes contributions from glycolysis, Krebs Cycle, and the Electron Transport Chain.