Photosynthesis and Respiration- Aerobic Respiration

Question 1

What is the process of the link reaction?

Answer 1

1. Pyruvate is decarboxylated
2. Pyruvate is oxidised to form acetate and NAD is reduced to form reduced NAD
3. Acetate is combined with CoA to form acetyl COA

Question 2

How many times does the link reaction occur for every glucose molecule?

Answer 2

Twice

Question 3

Where does the Krebs cycle take place?

Answer 3

In the matrix of the mitochondria

Question 4

What is the process of the Krebs cycle?

Answer 4

1. Acetyl CoA combines with oxaloacetate (4C) to form citrate (6C)
2. Decarboxylation occurs to make 6C molecule a 5C molecule and dehydrogenation occurs, and the hydrogen is used to produce reduced NAD from NAD
3. 5C molecule then converted to a 4C molecule (decarboxylation) and dehydrogenation occurs, and a 1 molecule of reduced FAD and 2 molecules of reduced NAD are produced
4. ATP is produced by the direct transfer of a phosphate group from an intermediate compound to ADP
5. Citrate has now been converted into oxyloacetate

Question 5

What are the products of the Krebs cycle?

Answer 5

1 coenzyme A, oxaloacetate, 2 CO2, 1 ATP, 3 reduced NAD, 1 reduced FAD

Question 6

Where does 1 coenzyme A go?

Answer 6

Reused in the next link reaction

Question 7

Where does oxaloacetate go?

Answer 7

Regenerated for use in the next Krebs cycle

Question 8

Where does 2 CO2 go?

Answer 8

Released as a waste product

Question 9

Where does 1 ATP go?

Answer 9

Used for energy

Question 10

Where does 3 reduced NAD go?

Answer 10

To oxidative phosphorylation

Question 11

Where does 1 reduced FAD go?

Answer 11

To oxidative phosphorylation

Question 12

What is oxidative phosphorylation?

Answer 12

The process where the energy carried by electrons, from reduced coenzymes is used to make ATP

Question 13

What does oxidative phosphorylation involve?

Answer 13

The electron transport chain and chemiosmosis

Question 14

What happens to the hydrogen atoms in oxidative phosphorylation?

Answer 14

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

Question 15

What happens to the electrons in oxidative phosphorylation?

Answer 15

They move down the electron transport chain, losing energy at each carrier

Question 16

How is the energy used in oxidative phosphorylation?

Answer 16

It is used by the electron carriers to pump protons from the mitochondrial matrix into the intermembrane space

Question 17

What happens to the concentration of protons in oxidative phosphorylation?

Answer 17

It is higher in the intermembrane space than in the mitochondrial matrix which forms an electrochemical gradient

Question 18

How do protons move in oxidative phosphorylation?

Answer 18

Down the electrochemical gradient, back across the inner mitochondrial membrane and into the mitochondrial matrix via ATP synthase- this drives the synthesis of ATP from ADP and inorganic phosphate

Question 19

What is chemiosmosis?

Answer 19

The process of ATP production driven by the movement of H+ ions across a membrane

Question 20

What happens in the mitochondrial matrix at the end of the transport chain in oxidative phosphorylation?

Answer 20

The protons, electrons and O2 combine to form water- oxygen is the final electron acceptor