5.7 Respiration

Question 1

State the four stages of respiration.

Answer 1

Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation

Question 2

What are the 3 stages of glycolysis?

Answer 2

Phosphorylation of glucose to hexose bisphosphate
Splitting hexose biphosphate into 2 triose phosphates
Oxidation of triose phosphates to pyruvate

Question 3

What is the end product of glycolysis- the first stage of respiration?

Answer 3

2 X Pyruvate

Question 4

Describe the link reaction (4)

Answer 4

Carboxyl group removed
This decarboxylation and then dehydrogenation produces an acetyl group
NAD becomes reduced
The acetyl group combines with enzyme A making acetyl CoA (that carries the acetyl group to the krebs cycle)

Question 5

Describe the krebs cycle, including how many carbons are in each compound.

Answer 5

Acetyl group released from CoA combines with oxaloacetate (4c) forming citrate (6c)
citrate decarboxylated dehydrogenated forming 5c compound
decaarboxylated dehydrogenated again forming 4c compound
substrate level phosphorylation when this 4c compound binds temporarily with CoA produces 1 ATP
dehydrogenated makes oxaloacetate

Question 6

Where does glycolysis occur

Answer 6

cytoplasm of cell

Question 7

where does the krebs cyce occur

Answer 7

mitochondrial matrix

Question 8

where does the link reaction occur

Answer 8

mitochondrial matrix

Question 9

Where does oxidative phosphorylation occur?

Answer 9

inner mitochondrial membrane

Question 10

Describe the process of oxidative phosphorlyation. (5)

Answer 10

Hydrogen splits into protons and electrons
electrons along electron transport chain
energy is produced
to pump protons into intermembrane space
creates proton gradient
protons diffuse down concentration gradient
flow through ATP synthase
Protons are accepted by oxygen

Question 11

How many stages are there in the Krebs cycle?

Answer 11

6

Question 12

How many molecules of rNAD are formed from one turn of the krebs cycle

Answer 12

3

Question 13

How many molecules of rFAD are formed from one turn of the krebs cycle?

Answer 13

1

Question 14

How many molecules of C02 are formed from 1 turn of the Krebs cycle?

Answer 14

2

Question 15

What does NAD do in respiration?

Answer 15

Hydrogen acceptor (consequently it becomes reduced)

Question 16

Which stages of respiration are aerobic?

Answer 16

Link reaction
Krebs cycle
Oxidative phosphorylation

Question 17

What happens to the pyruvate in anaerobic conditions? (3)

Answer 17

Converted to lactate or ethanol

rNAD is reoxidised so glycolysis can continue, generating 2 ATP

Question 18

How can carbohydrates be changed to be used in respiration? (1)

Answer 18

isomerase enzyme change them to glucose for respiration

Question 19

Why are lipids a better respiratory substrate than carbohydrates?

Answer 19

because they have more protons for oxidative phosphorylation

Question 20

How are lipids used in respiration? (4)

Answer 20

fatty acid combined with CoA
transported to matrix, broken to 2 acetyl groups each attached to CoA
this beta oxidation pathway generates rNAD/rFAD
acetyl groups released from CoA, enter krebs cycle

Question 21

How are proteins used in respiration? (2)

Answer 21

excess AA deaminated in liver (remove amine group resulting in urea) leaves a keto acid
keto acid enters respiration as pyruvate/acetate and enters krebs cycle

Question 22

What is the formula for the respiratory quotient? (1)

Answer 22

RQ= CO2 produced/ O2 consumed

Question 23

What properties of the mitochondrial inner membrane allow chemiosmosis to occur? (2)

Answer 23

it contains ATP synthase
large surface area
impermeable to H+ ions

Question 24

Why would a larger number of propton pores in the inner mitochondrial membrane result in a person less likely to gain weight? (6) UNFINISHED QUESTION

Answer 24

more proton pores means more H+ will leak back across the inner mitochondrial membrane
so less H+ will go through ATP synthase for every molecule of NAD, so these people need to produce more NAD***UNFINISHED ANSWER

Question 25

What are the 3 types of phosphorylation?

Answer 25

PHOTO
OXIDATIVE
SUBSTRATE LEVEL

Question 26

Why don’t maggots need such well developed transport systems and exchange surfaces as flies? (3)

Answer 26

larger SA:V
so shorter diffusion distance
Flies need more ATP for movement/flyinf/higher metabolic rate
flies have hard exoskeleton