12.0 Respiration

Question 1

What does respiration produce?

Answer 1

ATP

Question 2

What makes ATP a good source of energy?

Answer 2

Only a single hydrogen bond needs to be broken, releases a small amount of energy

Question 3

What are the four stages of aerobic respiration?

Answer 3

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

Question 4

What is the difference between aerobic and anaerobic respiration?

Answer 4

Aerobic uses oxygen while anaerobic does not

Question 5

Where do the four stages of respiration take place?

Answer 5

1. Glycolysis = cytoplasm
2. Link reaction = matrix
3. Krebs cycle = matrix
4. Oxidative phosphorylation = cristae membrane

Question 6

Where does anaerobic respiration take place?

Answer 6

Cytoplasm

Question 7

How much ATP is created in aerobic and anaerobic respiration?

Answer 7

38 in aerobic
2 in anaerobic

Question 8

What are the end products of aerobic respiration?

Answer 8

Carbon dioxide and water

Question 9

What are the end products of anaerobic respiration?

Answer 9

Animals = lactate
Plants/fungi = ethanol

Question 10

What is oxidation?

Answer 10

Loss of electrons or hydrogen atoms

Question 11

What is reduction?

Answer 11

The gain of electrons or hydrogen atoms

Question 12

What is NAD?

Answer 12

A coenzyme

Question 13

What are the three stages of glycolysis?

Answer 13

1. Phosphorylation of glucose into glucose phosphate
2. Production of triose phosphate
3. Oxidation of triose phosphate into pyruvate

Question 14

How is glucose converted into glucose phosphate?

Answer 14

2 ATP molecules undergo hydrolysis to become ADP. The 2 phosphate molecules bond to the glucose which lowers the activation energy for the link reaction

Question 15

How is triose phosphate created?

Answer 15

A glucose phosphate splits to become 2 molecules of triose phosphate

Question 16

How is triose phosphate converted into pyruvate?

Answer 16

A hydrogen molecule is removed from the triose phosphate by NAD to become NADH. 2 ADP molecules react with 2 triose phosphate to become 2 ATP molecules and 2 pyruvate molecules

Question 17

How many ATP molecules are created during glycolysis?

Answer 17

Net gain of 2

Question 18

What are the products of glycolysis?

Answer 18

2 ATP
2 pyruvate
2 NADH

Question 19

In anaerobic respiration what happens to pyruvate?

Answer 19

Converted to ethanol in plants and fungi and lactate in animals

Question 20

What happens to pyruvate in aerobic respiration?

Answer 20

It is taken to the mitochondrial matrix in order to take part in the link reaction

Question 21

What is the name of the reaction that uses pyruvate from glycolysis?

Answer 21

The link reaction

Question 22

What happens to the pyruvate in the link reaction?

Answer 22

It is oxidised to acetate

Question 23

Why can pyruvate enter the mitochondria but glucose cannot?

Answer 23

Pyruvate is smaller

Question 24

What molecule accepts the 2 hydrogens released from pyruvate in the link reaction?

Answer 24

NAD - it forms NADH

Question 25

What molecule combines with the acetate created during the link reaction?

Answer 25

Coenzyme A - it forms acetylcoenzyme A

Question 26

What is the overall equation for the link reaction?

Answer 26

Pyruvate + NAD + CoA = Acetyl CoA + NADH + CO2.

Question 27

What are the products of the link reaction?

Answer 27

2 NADH 2 acetyl CoA 2 CO2

Question 28

What process occurs after the link reaction in aerobic respiration?

Answer 28

The Krebs cycle

Question 29

What is a coenzyme?

Answer 29

A molecule which assists some enzymes in functioning. Those involved in respiration and photosynthesis carry Hydrogen atoms from one molecule to another.

Question 30

What are the 3 main coenzymes?

Answer 30

NAD - used throughout respiration; FAD - used in the Krebs cycle; NADP, used in photosynthesis.

Question 31

What is produced in a single krebs cycle?

Answer 31

3 NADH, 1 FADH, 1 x ATP, 2 x CO2

Question 32

What type of phosphorylation occurs in the Krebs cycle?

Answer 32

substrate-level phosphorylation

Question 33

Describe chemiosmosis

Answer 33

reduced NAD and reduced FAD release the hydrogen atom (H+/e-) they are carrying. the H+ build up in the matrix of the mitochondria. the e- enter the ETC. the electron (e-) moves along the chain releasing energy, this pumps the protons (H+) from the matrix into the intermembranal space. the H+ build up in the intermembranal space, then diffuse back into the matrix via a transport protein carrying ATP Synthase enzyme . this leads to the production of ATP = oxidative phosphorylation. oxygen is used as a final electron acceptor and proton acceptor. it removes the electron from the end of the ETC, so the ETC can continue. it removes the proton from the matrix, hence maintaining concentration gradient. it becomes wate

Question 34

How is oxidative phosphorylation carried out?

Answer 34

Electrons are transferred through a series of carier molecules which together form the Electron Transfer Chain.

Question 35

What is the role of oxygen in the ETC?

Answer 35

It acts as a final electron acceptor

Question 36

Why doesn't the ETC occur in anaerobic respiration?

Answer 36

No oxygen so no final electron acceptor

Question 37

Why doesn't the Krebs cycle and link reaction occur in anaerobic respiration?

Answer 37

reduced NAD and FAD are not regenerated in the ETC and so the process has to stop

Question 38

What is produced in anaerobic respiration in animals?

Answer 38

lactate

Question 39

What is produced in anaerobic respiration in plants/yeast?

Answer 39

ethanol and CO2

Question 40

What are the alternative respiratory substrates?

Answer 40

Amino acids - converted into pyruvate and intermediates in the Krebs cycle based on the number of carobs Fatty acids - become acetyl CoA and glycerol becomes triode phosphate