Respiration

Question 1

Why do we need respiration

Answer 1

To generate usable ATP for reactions in the body

Question 2

Processes which require cellular respiration

Answer 2

• active transport
• endocytosis
• Exocytosis
• dna replication
• cell division
• protein synthesis

Question 3

Site of aerobic respiration

Answer 3

Mitochondria

Question 4

Mitochondria labelled

Answer 4

Question 5

Features of mitochondria (structures in it)

Answer 5

Cristae
Matrix
Granules
Ribosome
Mitochondrial dna
Outer & inner (double) membrane

Question 6

Four stages of aerobic respiration

Answer 6

Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation

Question 7

Where does glycolysis occur

Answer 7

The cytosol (cell cytoplasm)

Question 8

Overall reaction is glucose -> 2 pyruvate molecules + 2ATP + 2red.NAD: why does glucose have to be converted to pyruvate

Answer 8

Glucose too big to enter mitochondria, but pyruvate can

Question 9

Main stages of glycolysis

Answer 9

1) phosphorylation of glucose to hexose biphosphate
2) splitting of hexose biphosphate into 2 T.P. Molecules
3) oxidation of TP molecules

Question 10

What’s the coenzyme involved in glycolysis

Answer 10

NAD

Question 11

What does NAD do in glycolysis

Answer 11

Accept H atoms from TP as it is oxidised, reducing NAD (x2)

Question 12

Stage 1 of glycolysis = phosphorylation of glucose to hexose biphosphate: what happens here?

Answer 12

Glucose is phosphorylated by 2 ATP molecules, forming hexose biphosphate & 2 ADP as waste products

Question 13

Where are the phosphate groups on hexose biphosphate

Answer 13

Carbon 1 & 6

Question 14

Stage 3 of glycolysis: oxidation of TP molecule: what happens here?

Answer 14

1. 2 TP molecules are oxidised to from to form 2 pyruvate molecules
2. Hydrogen atom removed from each TP molecule by dehydrogenase enzymes & coenzyme NAD
3. 2 NAD molecules accepts these H atoms & are reduced to from 2 reduced NAD molecules
4. ADP (4 of them) molecules phosphorylated-> 4 ATP

Question 15

In the link reaction, where does pyruvate from the cell cytoplasm go to?

Answer 15

The mitochondrial matrix

Question 16

How is pyruvate moved from the cytoplasm to the mitochondrial matrix

Answer 16

• actively transported across double membrane of mitochondria
• using transport protein and ATP

Question 17

Link reaction reactants

Answer 17

2 pyruvate + 2NAD + 2 CoA

Question 18

Link reaction products

Answer 18

2CO2 + 2 reduced NAD + 2 acetyle CoA

Question 19

Link reaction reactants & products equation

Answer 19

(This means the products of link reaction per glucose molecule btw x)

Question 20

The link reaction is the only stage where (…) isn’t produced

Answer 20

ATP

Question 21

What are the 2 stages of the link reaction

Answer 21

Oxidative decarboxylation & dehydrogenation of pyruvate
Formation of acetyl coenzyme A

Question 22

What happens in the oxidative decarboxylation & dehydrogenation of pyruvate

Answer 22

Question 23

How is acetyl coenzyme A formed

Answer 23

Question 24

Where does the 3rd stage of respiration: the Kreb’s cycle: occur

Answer 24

In the matrix of the mitochondria

Question 25

Function of the Krebs cycle

Answer 25

Oxidation of acetyl group from acetyl CoA to form CO2, reduced NAD & reduced FAS through the oxidation of citrate

Question 26

Products of the Krebs cycle (per glucose molecule - 2 cycles)

Answer 26

Question 27

Products of Krebs cycle per 1 cycle

Answer 27

3 reduced NAD 1 reduced FAD 2 carbon dioxide 1 ATP

Question 28

Link reaction linked to Krebs cycle diagram

Answer 28

Question 29

Explain the stages of the Krebs cycle using this diagram

Answer 29

1. Acetyl group from Acetyl CoA & OOA (oxalacetate) react to form citrate 2. Coenzyme A released 3. Citrate oxidised to form - 5C compound - 1 CO2 - 1 reduced NAD 4. 5C compound further oxidised to form 4C intermediate compound + 1CO2 + 1 reduced NAD 5. Substrate level phosphorylation occurs (ADP + phosphate group) producing 1 ATP 6. A series of enzyme - catalysed redox reactions occur: to produce 1 reduced NAD, 1 reduced FAD, & OAA is regenerated so the cycle can repeat

Question 30

What are the substrates that can be respired aerobically in the Kreb’s cycle

Answer 30

Fatty acids Glycerol Amino acids

Question 31

Coenzymes involved in respiration? (3)

Answer 31

NAD FAD Acetyl CoA

Question 32

What is acetyl CoA!

Answer 32

A nucleotide consisting of ribose, adenine & a vitamin

Question 33

What are coenzymes

Answer 33

Question 34

Where does the 4th stage of respiration: oxidative phosphorylation occur

Answer 34

Inner mitochondrial membrane

Question 35

Whats the movement of protons during oxidative phosphorylation

Answer 35

-> matrix -> inter membrane space -> matrix

Question 36

Steps of oxidative phosphorylation

Answer 36

Question 37

What is the chemiosmosis theory

Answer 37

Question 38

How is ATP formed as the protons re-enter the matrix

Answer 38

- flow of protons through proton channel in ATP synthase (located in the inner mitochondrial matrix) - causes conformational change in ATP synthase - this provides energy for ADP to combine with phosphate group

Question 39

Products of oxidative phosphorylation (per glucose molecule)

Answer 39

Water & 28 ATP

Question 40

Net gain of ATP per glucose per stage of respiration

Answer 40

Question 41

Why is the theoretical yield of ATP not usually achieved

Answer 41