respiration topic 5

Question 1

what is respiration?

Answer 1

a chemical process required to release energy from glucose, which is used to synthesise ATP

Question 2

what does ATP stand for?

Answer 2

adenine triphosphate

Question 3

what is ATP made of?

Answer 3

adenine, ribose, 3 phosphate groups

Question 4

where is the energy stored in ATP?

Answer 4

in the third bond

Question 5

how is ATP made?

Answer 5

photophosphorylation, oxidative phosphorylation, substrate level phosphorylation

Question 6

when does photophosphorylation occur?

Answer 6

during photosynthesis

Question 7

when does oxidative phosphorylation occur?

Answer 7

in the mitochondria during aerobic respiration

Question 8

when does substrate level phosphorylation occur?

Answer 8

when the phosphate comes from a donor molecule

Question 9

what is the order for the stages of respiration?

Answer 9

glycolysis
link reaction
krebs cycle
oxidative phosphorylation

Question 10

where does glycolysis occur?

Answer 10

in the cytoplasm

Question 11

what happens during glycolysis?

Answer 11

glucose (6c) uses 2ATP-2ADP to form glucose phosphate

this then splits into 2 triose phosphate (3c)

this then splits into 2 pyruvate (3c) by breaking down 2ATP into 2 ADP, and NAD into NADH

Question 12

what are the products from glycolysis?

Answer 12

2 pyruvate, 2 NADH and a net gain of 2 ATP

Question 13

what are the summarised stages of glycolysis?

Answer 13

phosphorylate glucose to glucose phosphate using ATP, produce triose phosphate, oxidation of triose phosphate into pyruvate

Question 14

what is needed before the Link Reaction can occur?

Answer 14

pyruvate and NADH need to be actively transported from the cytoplasm into the mitochondrial matrix

Question 15

where does the Link Reaction occur?

Answer 15

mitochondrial matrix

Question 16

what happens during the Link Reaction?

Answer 16

pyruvate (3c) is oxidised to form acetate (2c) (releases 1 carbon dioxide, NAD into NADH)

coenzyme A added to form acetyl co enzyme A (2c)

Question 17

what are the summarised stages of the Link Reaction

Answer 17

pyruvate is oxidised to form acetate, picks up hydrogen to become reduced NAD,acetate combines with co enzyme A to produce acetyl co enzyme A

Question 18

how many times does the Link reaction occur for every glucose molecule?

Answer 18

twice

Question 19

what are the products of the Link Reaction?

Answer 19

2 acetyl co enzyme A, 2 carbon dioxide, 2 reduced NAD

Question 20

where does the Krebs cycle occur?

Answer 20

in the mitochondrial matrix

Question 21

what happens during the Krebs Cycle?

Answer 21

acetyl co enzyme A (2c) reacts with oxoloacetate (4c) to release co enzyme A

this produces citrate (6c) which enters the Krebs cycle

2 carbon dioxide are lost, atp and pi are transferred into atp, fad is tranferred into reduced fad, and 3 nad are transferred into 3 reduced nad

Question 22

what are the products from 2 cycles?

Answer 22

2 co enzyme A, 2 oxoloacetate, 4 carbon dioxide, 2 atp, 6 reduced nad, 2 reduced fad

Question 23

where does oxidative phosphorylation occur?

Answer 23

in the mitochondrial inner membrane (cristae)

Question 24

what are the stages of oxidative phosphorylation?

Answer 24

1) hydorgen atoms released from NADH and FADH as they are oxidised to form NAD and FAD
2) hydrogen atoms split into protons and electrons
3) electrons move down the electron transport chain and lose energy at each carrier
4) energy used by electron carriers to pump protons from the mitochondrial matrix into the intermembrane space
5) concentration of protons higher in the intermembrane space than the mitochondiral matrix
6) this forms an electrochemical gradient
7) protons move down the electrochemical gradeint into the mitochondiral matrix via ATP synthase
8) this synthesises ATP from ADP and inorganic phosphate
9) ATP production from movement of hydrogen ions across a membrane= chemiosmosis
10) in the mitochondrial matrix at the end of the transport chain, protons/electrons/oxygen combine to form water
11) oxygen is the final electron acceptor

Question 25

how many ATP can be made by one glucose molecule?

Answer 25

32

Question 26

how can ATP production be affected?

Answer 26

by mitochondrial diseases

Question 27

when does anaerobic respiration occur?

Answer 27

in the absence of oxygen

Question 28

where does anaerobic respiration occur?

Answer 28

in the cytoplasm of the cell

Question 29

what happens to the pyruvate formed in glycolysis during anaerobic respiration?

Answer 29

reduced to form ethanol and carbon dioxide in plants and microbes, or lactate in animals by gaining the hydrogen from reduced NAD

Question 30

what happens in anaerobic respiration when the hydrogen is gained from reduced NAD?

Answer 30

NAD is oxidised so it can be reused in glycolysis, ensuring more ATP can continue to be produced

Question 31

how is lactate formed in animals?

Answer 31

gain hydrogen from reduced NAD, pyruvate becomes reduced

Question 32

why can anaerobic respiration not continue for a long period of time?

Answer 32

lactate is an acid so would begin to denature enzymes

Question 33

how is ethanol and carbon dioxide produced in plants?

Answer 33

gain hydrogen from reduced NAD

Question 34

why is aerobic respiration only 32% efficent?

Answer 34

protons leak across the mitochondrial membrane in oxidative phosphorylation

ATP is used to actively transport pyruvate and NADH into the matrix

some energy lost as heat

Question 35

why is anaerobic respiration less efficent than aerobic respiration?

Answer 35

only 2 ATP molecules are produced from 1 glucose molecule