5.2.2 - respiration

Question 1

first stage of respiration

Answer 1

glycolysis

Question 2

is glycolysis aerobic or anaerobic?

Answer 2

anaerobic - does not require oxygen

Question 3

first step of glycolysis

Answer 3

phosphorylation - uses 2 molecules of ATP and forms hexose bisphosphate

Question 4

what happens to hexose bisphosphate in glycolysis

Answer 4

splits into two TP molecules

Question 5

products of glycolysis

Answer 5

2 pyruvate molecules
2 NAD molecules
4 ATP (only a net gain of 2, as 2 are used in phosphorylation)

Question 6

substrate level phosphorylation

Answer 6

formation of ATP without the involvement of an electron transport chain.

Question 7

why is the link reaction called the link reaction?

Answer 7

it is the step that links anaerobic glycolysis in the cytoplasm to the aerobic steps of respiration

Question 8

how does pyruvate enter the mitochondrial matrix

Answer 8

active transport via specific carrier proteins

Question 9

decarboxylation

Answer 9

carbon dioxide being removed

Question 10

products of the link reaction

Answer 10

acetyl coA
reduced NAD
Co2

Question 11

what is the waste product of the link reaction

Answer 11

co2

Question 12

role of acetyl coA

Answer 12

delivers the acetyl group to the next stage of aerobic respiration (Krebs)

Question 13

where does the krebs cycle take place?

Answer 13

matrix

Question 14

products of the krebs cycle

Answer 14

FAD, NAD, small amounts of ATP, Co2

Question 15

first step of the krebs cycle

Answer 15

acetyl coA delivers an acetyl group to the Krebs cycle - combines with 4C oxaloacetate to form 6C citrate

Question 16

role of coenzymes

Answer 16

required to transfer protons, electrons and functional groups

Question 17

differences between NAD and FAD

Answer 17

• NAD takes part in all stages of cellular respiration, FAD only in krebs
• NAD accepts 1 hydrogen and FAD accepts 2
• NADH is oxidised at the start of the ETC, FAD is oxidised further along
• reduced NAD results in the synthesis of 3 ATP molecules, whilst FAD results in 2.

Question 18

what are coenzymes usually derived from?

Answer 18

vitamins

Question 19

where does oxidative phosphorylation take place?

Answer 19

cristae

Question 20

what are the products of the last stage of respiration

Answer 20

lots of ATP
h2o

Question 21

what is the role of oxygen in OP?

Answer 21

final electron aceptor

Question 22

what is the phosphorylation of ADP dependent on?

Answer 22

electrons moving along the electron transport chain

Question 23

how is water formed in OP?

Answer 23

hydrogens released from NAD and FAD combine directly with oxygen

Question 24

anaerobic respiration

Answer 24

resulting in the synthesis of smaller quantities of ATP, occurs in the absence of oxygen

Question 25

obligate anaerobes

Answer 25

cannot survive in the presence of oxygen - mainly prokaryotes

Question 26

facultative anaerobes

Answer 26

synthesise ATP by aerobic respiration if oxygen is present, but can switch to anaerobic - e.g yeast

Question 27

obligate aerobes

Answer 27

can only synthesise ATP in the presence of oxygen - e.g mammals (individual cels maybe not, but overall obligate aerobes)

Question 28

fermentation

Answer 28

process by which complec organic compounds are broken down into simpler inorganic compounds withouy the use of oxygen or involvement of an ETC.

Question 29

alcoholic fermentation - where?

Answer 29

occurs in yeast and some plant cells

Question 30

products of alcohol fermentation

Answer 30

ethanol and carbon dioxide

Question 31

why does the flow of electrons stop with no oxygen?

Answer 31

as it is the final electron acceptor

Question 32

what happens to the coenzymes when there is no oxygen

Answer 32

no flow of electrons so reduced NAD and FAD can not be oxidised as there is no where for the electrons to go

Question 33

what happens to the krebs and link reaction when no oxygen

Answer 33

comes to a stop as coenzymes cannot be regenerated

Question 34

lactate fermentation - where?

Answer 34

mammals

Question 35

lactate fermentation - what is the hydrogen acceptor? what enzyme catalyses this?

Answer 35

- pryruvate - lactate dehygrogenase

Question 36

what is pyruvate converted to in lactate fermentation ?

Answer 36

lactic acid

Question 37

what happens to lactcic acid ?

Answer 37

converted back to glucose in the liver in liver (but oxygen is needed)

Question 38

why is lactate fermentation not sustainable?

Answer 38

- reduced quantity of ATP produced would not be enough tio maintain vital processes - accumulation of lactic acid causes a fall in pH causing enzymes to be denatured

Question 39

differences between alcohol and lactate fermentation

Answer 39

- alochol fermentation is not a reversible process - ethanol produced instead of lactic acid - not a short term process

Question 40

respiratory substrates

Answer 40

organic molecule that is broken down to release energy for the synthesis of of ATP

Question 41

lipids and release of energy

Answer 41

release about twice as much energy as carbohydrates due to carbon hydrogen bonds

Question 42

lipids and co2 release

Answer 42

relatively less produced, as more o2 is needed

Question 43

respiratory quotient

Answer 43

RQ = co2 produced / o2 consumed

Question 44

RQ for carbs, protein and lipids

Answer 44

- carbohydrates = 1.0 - proteins = 0.9 - lipids = 0.7