Metabolism

Question 1

what are the 3 metabolic pathways?

Answer 1

anabolic
catabolic
amphibolic

Question 2

what is the anabolic pathway?

Answer 2

compounds are synthesised
requires energy

Question 3

what is the catabolic pathway?

Answer 3

molecules are broken down
produces energy

Question 4

what is the amphipathic pathway?

Answer 4

both anabolic and catabolic

Question 5

how does glucose use independent facilitated diffusion?

Answer 5

14 transporters (GLUT-1. GLUT-2 etc)
follow concentration gradient

Question 6

how does glucose use Na+ monosaccharide cotransport

Answer 6

carrier mediated
coupled with Na+
against glucose concentration gradient, with Na+ concentration gradient

Question 7

what are the first five steps known as in glycolysis?

Answer 7

preparatory phase

Question 8

what are the last five steps known as in glycolysis?

Answer 8

payoff phase

Question 9

what is the first stage of glycolysis? what catalyses it?

Answer 9

glucose to glucose-6-phosphase
ATP to ADP + Pi
hexokinase

Question 10

what is the second step of glycolysis? what is it catalysed by?

Answer 10

glucose-6-phosphate converted to fructose-6-phosphase
catalysed with phosphoglucose isomerase

Question 11

what happens in the third step of glycolysis? what is it catalysed by?

Answer 11

frictose-6-phosphase converted to fructose-1,6-biphosphase
ATP to ADP +Pi
catalysed by phosphofructokinase

Question 12

what happens in the fourth stage of glycolysis? what catalyses this?

Answer 12

fructose-1,6-biphosphate split into either glyceraldehyde-3-phosphase or dihydroxyacetone
catalysed by aldolase

Question 13

what happens to the two products of the fourth stage of glycolysis (the fifth stage of glycolysis)

Answer 13

glyceraldehyde-3-phosphate used for payoff phase
dihydroxyacetone converted to glyceraldehyde-3-phosphate

Question 14

what is the sixth stage of glycolysis? what catalyses this?

Answer 14

glyceraldehyde-3-phosphate converted to 1,3-diphosphoglycerate
uses Pi, NAD+
catalysed by glyceraldehyde-3-phosphate dehydrogenase

Question 15

what is the seventh stage of glycolysis? what catalyses this?

Answer 15

1,3-diphosphoglycerate converted to 3-phosphoglycerate
high energy phosphate bonds generate ATP
catalysed by phosphoglycerate kinase

Question 16

what is the eighth stage of glycolysis? what catalyses this?

Answer 16

3-phosphoglycerate converted to 2 phosphoglycerate
phosphate moves to different carbon
catalysed by phosphoglycerate mutase

Question 17

what is the ninth stage of glycolysis? what catalyses this?

Answer 17

2-phosphoglycerate converted to phosphoenolpyruvate
catalysed by enolase

Question 18

what is the tenth stage of glycolysis? what is this catalysed by?

Answer 18

phosphoenolpyruvate converted to pyruvate
catalysed by pyruvate kinase

Question 19

which stages of glycolysis are irreversible?

Answer 19

1. Glucose to glucose-6-phosphate
2. fructose-6-phosphate to fructose-1,6-biphosphate
3. phosphoenolpyruvate converted to pyruvate

Question 20

what happens to pyruvate in anaerobic conditions?

Answer 20

converted to lactate by lactate dehydrogenase
produces NAD+ to allow glycolysis continuation
lactate converted to glucose when o2 available

Question 21

what happens to pyruvate in aerobic conditions?

Answer 21

converted to acetyl coenzyme A by pyruvate dehydrogenase
enters the TCS cycle in the mitochondria

Question 22

what can acetyl CoA accumulation lead to?

Answer 22

fatty acid and ketone bodies synthesis

Question 23

what is the two reactions in the pentose phosphate pathway?

Answer 23

irreversible oxidative reaction
reversible non-oxidative reaction

Question 24

why is the pentose phosphate pathway important?

Answer 24

provides body with pentoses for nucleotide production
generate NADPH

Question 25

what happens to pentose phosphate pathway overspill?

Answer 25

enters glycolysis as fructose-6-phosphate

Question 26

what happens in the irreversible oxidative reaction of the PPP?

Answer 26

gluocose-6-phosphate to 6-phosphogluconolactone using glucose-6-phosphate dehydrogenase 6-phosphoglunolactone to ribulose-5-phosphate using dehydrogenase 2 NADP+ reduced to 2NADPH

Question 27

what happens in the reversible non-oxidative reaction of the PPP?

Answer 27

ribulose-5-phosphate undergoes isomerisation

Question 28

what is gluconeogenesis?

Answer 28

metabolic process where organisms produce glucose from non-carbohydrates

Question 29

what substrates are used in gluconeogenesis?

Answer 29

glycerol from triacyl glycerol hydrolysis in adipose tissue lactate from muscles during exercise amino acids from tissue protein hydrolysis

Question 30

which steps does gluconeogenesis by pass? why?

Answer 30

1,3,10 they are irreversible

Question 31

what is glycogen?

Answer 31

B polymer of glucose storage molecule of glucose doesn't affect osmotic balance extra glucose converted to lipids

Question 32

what happens during glycogenesis?

Answer 32

glucose-6-p to glucose-1-p to UDP-glucose which delivers glucose to growing glycogen

Question 33

what does cAMP do?

Answer 33

initiates a series of reactions that lead to the activation of phosphorylase transforms enzyme to active

Question 34

what is the bases of the TCA cycle?

Answer 34

where oxidative metabolism of carbohydrates, amino acids and fatty acids meet

Question 35

where does the TCA occur?

Answer 35

the mitochondria

Question 36

what happens just before the TCA cycle starts?

Answer 36

pyruvate moves to the mitochondria oxidative carboxylation

Question 37

what is the first step of the TCA cycle

Answer 37

oxaloacetate joins acetyl-CoA to from citrate catalysed by citrate synthase

Question 38

what is the second step of the TCA cycle?

Answer 38

citrate undergoes isomerisation forms isocitrate catalysed by aconitase

Question 39

what is the third step of the TCA cycle?

Answer 39

isocitrate undergoes oxidative carboxylation forms a-ketoglutarate NADH formed CO2 formed catalysed by isocitrate dehydrogenase

Question 40

what is the fourth step of the TCA cycle?

Answer 40

a-ketoglutarate undergoes oxidative decarboxylation forms succinyl-CoA catalysed by a-ketoglutarate dehydrogenase forms NADH forms CO2`

Question 41

what cofactors are needed in the fourth step of the TCA cycle?

Answer 41

TPP FAD NAD CoA

Question 42

what happens in the fifth step of the TCA cycle?

Answer 42

succinyl-CoA releases energy forms succinate catalysed by succinate thiokinase

Question 43

what is the sixth step of the TCA cycle?

Answer 43

succinate oxidised forms fumarate forms FADH2 catalysed by succinate dehydrogenase

Question 44

what is the seventh step of the TCA cycle?

Answer 44

fumarate hydrated forms malate catalysed by fumarase

Question 45

what is the eighth step of the TCA cycle?

Answer 45

malate oxidised forms oxaloacetate forms NADH catalysed by malate dehydrogenase

Question 46

what does the TCA produce?

Answer 46

2 CO2 3 NADH 1 FADH2 1 ATP

Question 47

what are the electron carriers associated with the inner mitochondria membrane

Answer 47

Complex I Complex II Co-Q (quinone) Complex III Cytochrome-c Complex IV (cytochrome oxidase) Complex V (ATP synthase)

Question 48

how many ATP molecules are made from one glucose molecule?

Answer 48

38

Question 49

what does glycolysis overall produce?

Answer 49

8 ATP 2 NADH

Question 50

what does the TCA cycle produce?

Answer 50

2 NADH 6ATP

Question 51

what does oxidative phosphorylation produce?

Answer 51

6 NADH 2 FADH 2GTP 26 ATP