Respiration (only key points so refer to notes)

Question 1

what does respiration do?

Answer 1

releases energy stored in organic molecules (glucose)
the energy is used to synthesise ATP
ATP is hydrolysed to release energy which drives biological processes

Question 2

anabolic reactions

Answer 2

large molecules synthesised from small

Question 3

catabolic reactions

Answer 3

large molecules hydrolysed (broken down) to small ones

Question 4

ATP is a ……

structure of ATP:

Answer 4

phosphorylated nucleotide
adenosine = adenine + ribose (5 carbon sugar)
and 3 phosphate groups

Question 5

properties of ATP

Answer 5

relatively stable so doesn’t break down in solution

readily hydrolysed by catalysis (enzyme)

Question 6

Glycolysis occurs in the……

Answer 6

cytoplasm

Question 7

3 main stages of glycolysis

Answer 7

phosphorylation of glucose to hexose bisphosphate
splitting of hexose bisphosphate into 2 triose phosphates
oxidation of triose phosphate to pyruvate

Question 8

NAD

Answer 8

coenzyme
accepts H atoms removed during oxidation
helps dehydrogenase enzymes carry out oxidation
reduced NAD gives up protons/electrons that accepted

Question 9

NADH structure

Answer 9

nicotinamide ring + 2 hydrogen atoms

Question 10

products of glycolysis

Answer 10

2 NADH
4 ATP made
2 net ATP because 2 used to start glycolysis process
2 pyruvate

Question 11

4 main stages of respiration

Answer 11

Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation

Question 12

diameter of mitochondria

length of mitochondria

Answer 12

0.5-1.0μm

2-5μm

Question 13

mitochondrial matrix

features and what contains

Answer 13

semi-rigid
gel-like

contains mitochondrial ribosomes - proteins assembled
looped mitochondrial DNA codes for enzymes/proteins
enzymes for Link reaction + Krebs cycle
contain NAD, FAD
oxaloacetate used in Krebs cycle

Question 14

adaptations of inner mitochondrial membrane

Answer 14

lipid composition differs so less permeable to small ion
cristae = large SA for electron carriers for electron transport chain
and ATP synthase enzymes

Question 15

how does pyruvate enter the Link reaction after glycolysis?

Answer 15

transported across outer and inner membranes via specific pyruvate-proton symport (transport protein) to matrix

Question 16

put simply, what happens to pyruvate in the Link reaction?

and what happens to this product in the Krebs cycle?

Answer 16

pyruvate converted to 2-carbon acetyl group (decarboxylated and dehydrogenated)

acetyl group oxidised

Question 17

what are the products of the Link reaction?

Answer 17

2 acetyl CoA
2 H
2 CO₂
2 reduced NAD

Question 18

substrate level phosphorylation

Answer 18

4C compound temporarily added to then released from CoA which makes ATP from ADP and Pi

Question 19

which enzyme catalyses rearrangement of 4C compound in Krebs cycle?

Answer 19

isomerase enzyme

Question 20

how many turns of Krebs cycle for 1 glucose?

Answer 20

2

Question 21

what other substances can be used in respiration and how?

Answer 21

fatty acids broken down to acetate and enter Krebs cycle
glycerol turns to pyruvate and enter Link reaction
amino acids deaminated then enter Krebs cycle or changed to pyruvate or acetyl CoA

Question 22

products of the Krebs cycle for every glucose

Answer 22

6 reduced NAD because 3 in each cycle and has to go round twice for every glucose
2 reduced FAD
4CO₂
2ATP

Question 23

products of glycolysis, Link reaction and Krebs cycle for every glucose?

Answer 23

10 NADH
2 FADH
4 ATP
6 CO2