5.2 Resporation

Question 1

Description of a mitochondria

Answer 1

Outer membrane

Cristae(inner membrane fold)

Matrix:
(70 ribosomes)
Circular dna

Question 2

General stages of respiration
Aerobic and anaerobic

Answer 2

Aerobic:
-glycolysis -cytoplasm
-link reaction- matrix of mitochondria
-krebs cycle, matrix of mitochondria
-oxidative phosphorylation, inner mitochondria membrane

Anaerobic
-glycolysis, cytoplasm
-NAD regeneration, cytoplasm

Question 3

Process of glycolysis

Answer 3

Glucose is phosphorylated to glucose phosphate (using 2x ATP)

It’s then hydrolysed to 2x triose phosphate

Then oxidised to 2x pyruvate
2x NAD being reduced
4x ATP regenerated ( overall 2x gain)

Question 4

What happens in anaerobic respiration

Answer 4

Glycolysis

Pyruvateis converted to lactate (animals)or ethanol (plants or yeast)

Reduced NAD is oxidised producing NAD

So glycolysis can continue (NAD is regenerated )

Question 5

Why does anaerobic produce less ATP than aerobic

Answer 5

Only glycolysis (2 molecules of ATP)

No oxidative phosphorylation which forms the majority of ATP (about 34 molecules)

Question 6

Link reaction

Answer 6

Pyruvate oxidised to acetate
-Co2 is produced
-NAD is reduced

Acetate combines with coenzyme A, forming Acetyl coenzyme A

Question 7

What does the link reaction produce per glucose molecule

Answer 7

2x acetyl coenzyme A
2x Co2
2x reduced NAD

Question 8

Krebs cycle

Answer 8

Acetyl coenzyme A (2c) reacts with a 4C
-releasing coenzyme A
-producing a 6c molecule that enters the Krebs cycle

In a series of oxidation-reduction reactions, the 4C molecule is regenerated
-2x Co2 is lost
-3x NAD is reduced
-FAD is reduced
-ATP produced

Question 9

Products per glucose of the Krebs cycle

Answer 9

6x reduced NAD
2x reduced FAD
2x ATP
4x Co2

Question 10

Process of oxidative phosphorylation

Answer 10

1) reduced NAD/FAD is oxidised to release H atoms and electrons

2) electors transferred down the electron transfer chain
-by redox reactions

3) energy released by electrons is used in the production of ATP from ADP and pi
-energy used by electron carriers to actively pump H into the matrix
-H diffuse into matrix by electrochemical gradient, via ATP synthase, releasing energy to synthesise ATP from ADP and pi

4) in matrix end of ETC, O is the final electron acceptor
So H, O and electrons combine to form water

Question 11

Examples of other respiratory substances

Answer 11

Fatty acids from the hydrolysis of lipids - converted to Acetyl coenzyme a

Amino acids from hydrolysis of proteins - converted to intermediate in Krebs cycle