Energy transfer in and between organisms - RESPIRATION

Question 1

Where does glycolysis occur?

Answer 1

Cytoplasm

Question 2

Where does the link reaction occur?

Answer 2

Mitochondrial matrix

Question 3

Where does the Krebs cycle occur?

Answer 3

Mitochondrial matrix

Question 4

Where does oxidative phosphorylation occur?

Answer 4

Inner mitochondrial membrane

Question 5

Give a summary of glycolysis

Answer 5

• Phosphorylation
• Splitting of glucose

Question 6

Give a summary of the Link reaction

Answer 6

• Decarboxylation
• Dehydrogenation of pyruvate

Question 7

Give the summary of the Krebs cycle

Answer 7

Cyclical pathway of enzyme controlled reactions
- complete oxidation and breakdown of pyruvate

Question 8

Give a summary of oxidative phosphorylation

Answer 8

Production of ATP through the oxidation of hydrogen atoms

Question 9

What is the first step of glycolysis?

Answer 9

• Glucose is phosphorylated using 2x ATP
• Converted into fructose bisphosphate

Question 10

What is the second step of glycolysis?

Answer 10

Fructose bisphosphate converted into 2x triose phosphate

Question 11

What is the third step of glycolysis?

Answer 11

• Triose phosphate converted into pyruvate
• NADH+ and 2x ATP produced

Question 12

What is the net gain of products in glycolysis?

Answer 12

2x ATP and 2x NADH+

Question 13

What are coenzymes?

Answer 13

Molecules which some enzymes need to function (NOT enzymes themselves)

Question 14

What is the role of dehydrogenase enzymes?

Answer 14

Catalyses removal of H

Question 15

What is NAD and what does it get reduced to?

Answer 15

• Coenzyme
• Hydrogen carrier
• Reduced into NADH+

Question 16

How is pyruvate moved into the mitochondrial matrix?

Answer 16

Active transport

Question 17

How many carbons does pyruvate have?

Answer 17

3

Question 18

What is decarboxylation? (Link reaction)

Answer 18

Removal of CO2 from the pyruvate

Question 19

What is pyruvate converted into during the link reaction?

Answer 19

3C -> 2C
Two carbon compound called Acetyl CoA

Question 20

What type of reaction is the conversion of pyruvate to Acetyl CoA?

Answer 20

Oxidation reaction

Question 21

How many times does the Krebs cycle turn during the aerobic respiration of glucose?

Answer 21

Twice

Question 22

What carbon chains are produced during the Krebs cycle? (starting from 2C)

Answer 22

1. Acetyl CoA (2C)
2. Citrate (6C)
3. Intermediate compound (5C)
4. Oxaloacetate (4C)

Question 23

Where does the electron transport chain occur?

Answer 23

Inner membrane/cristae

Question 24

How many ATP does the electron transport chain produce?

Answer 24

34 ATP

Question 25

Which coenzymes are involved in the ETC?

Answer 25

NADH and FADH

Question 26

Why are electron transferred along a number of carrier molecules at slightly lower energy levels?

Answer 26

• Creates electrochemical gradient with H
• Used to pump H each time

Question 27

How is substrate level phosphorylation different to oxidative phosphorylation?

Answer 27

Substrate level: Phosphate is provided by another phosphate
Oxidative: Requires ATP synthase to generate ATP

Question 28

What enzyme removes H from the coenzymes in the ETC?

Answer 28

Dehydrogenase

Question 29

What happens in the inner membrane stage of the ETC if there is not enough oxygen?

Answer 29

Oxygen is the final electron acceptor
- If there is no oxygen, protons build up
- No ATP is formed

Question 30

Anaerobic word equations in plants and animals

Answer 30

Plants : Glucose -> Lactate
Animals : Glucose -> CO2 + ethanol

Question 31

What happens if there is no oxygen?

Answer 31

• The ETC stops functioning
• No more ATP is produced via oxidative phosphorylation
• Reduced NAD and FAD aren’t oxidised by an ETC
• No oxidised NAD and FAD are available for dehydrogenation in the Krebs cycle
• Krebs cycle stops