Unit 5 - respiration

Question 1

what are the 2 ways ATP is made in cells?

Answer 1

substrate level phosphorylation: energy released from catabolic reactions

oxidative phosphorylation: removal of hydrogen from intermediate compound in metabolic pathway e.g. electron transport chain

Question 2

one molecule of ATP contains…

Answer 2

adenine
ribose
3 x phosphate groups

Question 3

4 parts of aerobic respiration

Answer 3

1. glycolysis
2. link reaction
3. krebs cycle
4. electron transport chain

Question 4

where does glycolysis occur?

Answer 4

in cytoplasm

Question 5

where does link reaction occur? where does krebs cycle occur?

Answer 5

both in mitochondrial matrix

Question 6

where does the ETC occur?

Answer 6

inner membrane/ cristae of mitochondria

Question 7

What occurs in anaerobic respiration? where? how much energy? waste products?

Answer 7

glycolysis
cytoplasm
2 ATP
lactic acid / ethanol + CO2

Question 8

where is NAD regenerated in mammals?

Answer 8

lactate pathway

Question 9

what is lactate?

Answer 9

by-products of anaerobic cellular respiration. Any time a cell uses anaerobic respiration (glycolysis and fermentation), it will produce lactic acid that will dissociate into lactate ions and hydrogen ions.

Question 10

where does the lactate move in lactate pathway?

Answer 10

out of cell into the blood

Question 11

why does the ph change in Anaerobic respiration? and how does it change?

Answer 11

pH LOWERS because of increased H+ ions (more acidic)

Question 12

how does lower pH affect CNS + muscle impulses?

Answer 12

less nerve impulses arrive at the muscle, leading to less muscle conctraction

Question 13

when excersize stops lactate levels remain high due to oxygen debt. How does the body reduce lactate levels?

Answer 13

when O2 is available lactate is oxidised BACK into pyruvate, where it can enter the krebs cycle

Question 14

athletes can tolerate higher levels of lactate? why?

Answer 14

they have more lactate transport molecules, oxidation of lactate is faster

Question 15

what is pyruvate broken down into in Plants + fungi?

Answer 15

ethanol
CO2
2 x ATP

Question 16

glycolysis

Answer 16

glucose (5C) > 6C mol > phosphorylated 6C > 2 x TP (3C) > pyruvate (3C)

Question 17

what happens to 2 TP molecule in glycolysis

Answer 17

they are OXIDISED(lose H) to produce pyruvate

Question 18

what does a single TP molecule produce in glycolysis?

Answer 18

2 x ATP and NADH

Question 19

net gain in glycolysis?

Answer 19

2 ATP
2 NADH

Question 20

what is produced in the link reaction?

Answer 20

acetyl CoA (2C)

Question 21

what happnes during conversion of pyruvate into Acetyl coA in link reaction?

Answer 21

NAD is reduced into NADH

coA is decarboxylatedinto CO2

pyruvate is oxidised int acetyl coA

Question 22

net gain in link reaction?

Answer 22

The net gain from the link reaction is:
1 CO2 molecule.
1 NADH molecule.

Question 23

what occurs to acetyl CoA in krebs cycle?

Answer 23

acetyl coA joins w 4C mol > 6C

Question 24

what happens to the 6C mol in krebs cycle?

Answer 24

the molecule is decarboxylated to produce CO2, it is also dehydrogenated and NADH is formed

acetyl coA is now a 5C mol

Question 25

what happens to 5C mol in krebs cycle?

Answer 25

The five-carbon molecule is decarboxylated and dehydrogenated again to a four-carbon compound.

CO2 is produced.
NADH are produced.
ATP is also produced by substrate-level phosphorylation.

Question 26

what happens to 4C mol in krebs cycle?

Answer 26

dehydrogenated again to produce another molecule of NADH.
FAD is also reduced to FADH2.

No decarboxylation takes place at this stage.

Question 27

net gain of krebs cycle?

Answer 27

2 CO2 molecules.
3 NADH molecules.
1 ATP molecule.
1 FADH2 molecules.

Question 28

how many times does the krebs cycle need to occur for 1 mol of glucose?

Answer 28

2 cycles needed
(this is because two molecules of pyruvate are produced in glycolysis).