Areobic Respiration

Question 1

Where does glycolysis take place?

Answer 1

Cytoplasm of cell

Question 2

What are the 4 stages of aerobic respiration

Answer 2

1. Glycolysis
2. Link reaction
3. Kerbs cycle
4. Oxidative phosphorylation

Question 3

What sort of reaction is glycolysis?

Answer 3

Anaerobic

Question 4

Describe stage 1 of glycolysis (phosphorylation)

Answer 4

1. Glucose iS phosphorylated by adding 2 phosphates from 2 molecules of ATP
2. This creates 2 molecules of triose phosphate and 2 of ADP

Question 5

Describe stage 2 of glycolysis (oxidation)

Answer 5

1. Triose phosphate is oxidised (loses hydrogen) forming 2 pyruvate
2. NAD collects the hydrogen ions forming reduced NAD
3. 4 ADP + 4Pi produce 4 ATP (so net gain of 2)

Question 6

How much ATP is produced at each stage?

Answer 6

Glycolysis: 2 (acc 4 but 2 used for phosphorylation)

Question 7

What are the products of each stage?

Answer 7

Glycolysis: 2 Reduced NAD (used in last stage)
2 pyruvate molecules
-
Link reaction: acetyl CoA and Co2 (waste)
-
Krebs cycle: see card

Question 8

Where do the two pyruvate go from glycolysis?

Answer 8

Matrix of mitochondria for link reaction

Question 9

Where are the enzymes and coenzymes located for link reaction?

Answer 9

Mitochondrial matrix

Question 10

Describe the steps of the link reaction (4 steps)

Answer 10

1) pyruvate is decarboxylated- 1 C atom removed to form Co2
2) NAD is reduced- NAD collects H from pyruvate turning it into Acetate
3) Acetate is combined with coenzyme A to form Acetyl CoA
4) no ATP is produced

Question 11

How many carbon atoms does acetyl CoA have?

Answer 11

2C

(pyruvate (3C) decarboxylated to form Co2

Question 12

Why do the link reaction and Krebs cycle happen twice for every glucose molecule?

Answer 12

Two pyruvate are made for every glucose molecule

Question 13

For each glucose molecule, what is produced in the first 2 stages

Answer 13

1. 2 molecules of acetyl CoA
2. Two Co2 molecules
3. Two molecules of reduced NAD

Question 14

Where does each reaction take place?

Answer 14

Glycolysis: cytoplasm
Link reaction: mitochondrial matrix
Krebs cycle: matrix
Oxidative phosphorylation: mitochondrial membrane

Question 15

Describe stage 1 of Krebs cycle

Answer 15

1. Acetyl CoA combines with oxaloacetate for form citrate (6C)
2. Coenzyme A recycled to link reaction

Question 16

Describe stage 2 of Krebs cycle

Answer 16

1. Citrate is decarboxylated (Co2 is removed) to a 5c molecule
2. Dehydrogenation occurs (H used to produce reduced NAD)

Question 17

Describe stage 3 of Krebs cycle

Answer 17

1. 5C molecule converted to 4C molecule (don’t ask how)
2. Decarboxylation and dehydrogenation, producing one molecule of reduced FAD and two of reduced NAD
3. ATP is produced by direct transfer of phosphate to ADP
4. Citrate has now been converted to oxaloacetate

Question 18

What are the 6 products of the Krebs cycle

Answer 18

1. 1 coenzyme A (reused in link)
2. Oxaloacetate (regenerated for Krebs)
3. 2 CO2 (released)
4. 1 ATP
5. 3 reduced NAD (used in OP)
6. 1 reduced FAD (OP)

Question 19

Sum up oxidative phosphorylation

Answer 19

Process where energy carried by electrons from coenzymes (reduced NAD and FAD) is used to make ATP

Question 20

What are the 2 parts of oxidative phosphorylation

Answer 20

1. Electron transport chain

2. Chemiosmosis

Question 21

Stage 1 of oxidative phosphorylation

Answer 21

Hydrogen atoms are released from reduced NAD and FAD as they’re oxidised. H atoms split into protons and electrons

Question 22

Stage 2 of oxidative phosphorylation (electron transport)

Answer 22

Electrons move down electron transport chain (made of electron carriers), losing energy at each carrier

Question 23

What is the energy released from the electron used for? (Stage 3)

Answer 23

To pump protons from mitochondrial matrix into inter-membrane space

Question 24

Stage 4 of oxidative phosphorylation (what does proton pump create?)

Answer 24

Conc of protons now higher in intermembrane space than in matrix. Forms an electrochemical gradient

Question 25

Stage 5 of oxidative phosphorylation (protons move)

Answer 25

Protons move down electrochemical gradient via enzyme ATP-synthase.
This movement drives synthesis of ATP from ADP and Pi

Question 26

Which part is chemiosmosis

Answer 26

Movement of protons across membrane creating ATP

Question 27

Stage 7 of oxidative phosphorylation( final stage)

Answer 27

In matrix, protons, electrons and O2 from blood combine to form water. Oxygen final electron acceptor

Question 28

What doesn’t anaerobic respiration use

Answer 28

1. Oxygen

2. Link reaction, Krebs cycle or Oxidative phosphorylation