Respiration 3.5.2

Question 1

Name 3 respiratory substrates?

Answer 1

Glucose, Lipids, Amino Acids

Question 2

State the formula for Aerobic Respiration

Answer 2

C6H12O6 + 6O2  6CO2 + 6H2O + ATP

Question 3

Where does glycolysis occur?

Answer 3

Cytoplasm

Question 4

What type of respiration can occur in glycolysis?

Answer 4

It will occur in both aerobic and anaerobic respiration as no oxygen is needed.

Question 5

What is glucose turned into during glycolysis?

Answer 5

First turned to triose phosphate and then pyruvate (3C)

Question 6

Explain fully the process of glycolysis?

Answer 6

a) Phosphorylation of glucose to form glucose phosphate and ATP is needed.
b) Then glucose phosphate splits into 2 triose phosphates.
c) Triose phosphate oxidised to form pyruvate and a net gain of 2 ATP by substrate level Phosphorylation
d) Reduced NAD is produced

Question 7

How is ATP produced during glycolysis?

Answer 7

This is done by Substrate level Phosphorylation

Question 8

State the 3 products in glycolysis?

Answer 8

a) 2 pyruvate
b) Net gain of 2 ATP
molecules
c) 2 Reduced NAD

Question 9

Give 2 reasons why Glucose is phosphorylated?

Answer 9

a) Makes Glucose more reactive

b) Traps Glucose inside cell

Question 10

Where does the link reaction occur?

Answer 10

Matrix of mitochondria

Question 11

How is pyruvate taken to the matrix of the mitochondria?

Answer 11

Pyruvate (3C) is actively transported into matrix

Question 12

Explain fully what happens in the Link Reaction?

Answer 12

a) Pyruvate (3C) is oxidised to acetate (2C),
b) NAD is reduced
c) CO2 produced by
decarboxylation
d) Acetate combines with coenzyme A to make Acetylcoenzyme A (2C)

Question 13

Where does the Krebs cycle occur?

Answer 13

In the matrix of the mitochondrion

Question 14

How is ATP produced during the Krebs cycle?

Answer 14

This is via substrate level Phosphorylation.

Question 15

15. Explain fully what happens during the Krebs cycle?

Answer 15

a) Acetylcoenzyme A (2C) reacts with a 4C molecule producing a 6C molecules
b) 2 CO2 molecules produced
c) Oxidation + Reactions occur producing 3 reduced NAD and 1 Reduced FAD
d) 1 ATP produced per cycle by substrate level Phosphorylation

Question 16

16. Where does the Electron Transfer Chain occur?

Answer 16

In the inner mitochondrial membrane

Question 17

What is the Electron Transfer Chain?

Answer 17

This is when electrons are passed along a chain of carriers (protein)

Question 18

How is ATP produced in the electron transfer chain?

Answer 18

This is by Oxidative Phosphorylation

Question 19

Explain fully the Chemiosmotic theory which explains what happens in the electron transfer chain

Answer 19

a) Reduced NAD + reduced FAD are oxidised when they pass H atoms to the 1st carrier
b) Hydrogen splits into electrons + protons
c) Electrons pass down a chain of protein carriers(ox/red)
d) Carriers at decreasing energy levels so energy is released as electrons from carrier to carrier
e) Some energy used to actively transport protons from matrix through IMM, into intermembrane space. Also, some energy lost as heat
f) At the end of chain, protons diffuse back into matrix (facilitated diffusion), through ATP Synthase + Energy is released which is used to phosphorylate ADP to ATP
g) Oxygen is the final acceptor of the electron transfer chain. It combines with protons + electrons to make water

Question 20

How many ATP molecules formed during respiration?

Answer 20

38

Question 21

How is ATP produced in glycolysis + Krebs cycle?

Answer 21

Substrate level Phosphorylation

Question 22

How is ATP produced in the electron transfer chain?

Answer 22

Oxidative Phosphorylation

Question 23

Where does anaerobic respiration occur?

Answer 23

Cytoplasm

Question 24

Is NAD reoxidised? If So why?

Answer 24

This is because there is a limited supply so NAD must be reoxidised to allow glycolysis to continue. If it was all reduced, glycolysis would stop.

Question 25

What happens in animal cells during anaerobic respiration?

Answer 25

a) Glycolysis occurs to produce pyruvate
b) Net gain of 2 ATP via substrate level Phosphorylation
c) NAD is reduced
d) Pyruvate is then converted to lactate (lactic acid) (3C)

Question 26

What happens in plant cells during anaerobic respiration?

Answer 26

a) Glycolysis occurs to produce pyruvate
b) Net gain of 2 ATP via substrate level Phosphorylation
c) NAD is reduced
d) Pyruvate is then converted to ethanol (2C) + CO2

Question 27

Why is anaerobic respiration useful?

Answer 27

It is a fast way of producing small amounts of ATP

Question 28

28. What happens when oxygen becomes available?

Answer 28

Lactate is converted to pyruvate. Hence, Link reaction can occur.

Question 29

The tap is closed. After 30 mins the drop of coloured liquid moved to the left. Why? ( reference to fig. 1 )

Answer 29

a) O2 is used up by woodlouse
b) CO2 released is absorbed by potassium hydroxide
c) This leads to a lower volume, hence, lower pressure in experimental tube

Question 30

30. What measurements should be taken to calculate rate of aerobic respiration in mm3 / g-1 / h-1

Answer 30

a) Volume of cylinder =
πr2l (mm3)
b) Mass of woodlouse
c) Time taken for bubble to move (hours)

Question 31

Explain why one of the enzymes during link reaction is called pyruvate dehydrogenase?

Answer 31

This is due to the removal of hydrogen atoms from pyruvate which reduces NAD