biochemistry 1

Question 1

what is the first stage of glycolysis called

Answer 1

energy investment

Question 2

what is the second stage of glycolysis called

Answer 2

energy generation

Question 3

what converts glucose into glucose 6 phosphate

Answer 3

glucokinase or hexokinase
and ATP

Question 4

where is glucokinase found

Answer 4

liver and pancreas

Question 5

what converts glucose-6phosphate to fructose-6- phosphate

Answer 5

phosphoglucose isomerase

Question 6

what converts glucose-6-phosphate to fructose-1,6-bisphosphate

Answer 6

phosphofructokinase-1
and ATP

Question 7

what converts fructose-1,6-bisphophate to glyceraldehyde-3-phosphate

Answer 7

aldolase

Question 8

what converts fructose-1,6-bisphosphate to dihydroxyacetone phosphate

Answer 8

aldolase

Question 9

what converts dihydroxyacetone phosphate to glyceraldehyde-3-phosphate

Answer 9

triose phosphate isomerase

Question 10

why is there phosphorylation in the energy investment stage

Answer 10

• destabilisation of carbon-carbon bonds

Question 11

what converts glyceraldehyde-3-phsopahte t0 1,3-bisphosphoglycerate

Answer 11

glyceraldehyde-3-phosphate dehydrogenase and NAD+

Question 12

what converts 1,3-bisphosphoglycerate to 3-phosphoglycerate

Answer 12

phosphoglycerate kinase and ADP

Question 13

what converts 3-phosphoglycerate to 2-phosphoglycerate

Answer 13

phosphoglycerate mutase

Question 14

what converts 2-phophoglycerate to phosphoneolpyruvate

Answer 14

• H20
  enolase

Question 15

what converts phosphoneolpyruvate to pyruvate

Answer 15

pyruvate kinase and ADP

Question 16

how many ATP are produced from anaerobic glycolysis

Answer 16

2

Question 17

how many ATP are produced from aerobic glycolysis

Answer 17

7

Question 18

how many ATP are produced from aerobic respiration

Answer 18

32

Question 19

what is hexokinase inhibited by

Answer 19

glucose-6-phosphate

Question 20

what is phosphofructokinase-1 inhibited by

Answer 20

ATP and citrate

Question 21

what is phosphofructokinase-1 activated by

Answer 21

AMP,fructose-2,6-bisphosphate

Question 22

what is pyruvate kinase inhibited by

Answer 22

ATP and alanine

Question 23

what is private kinase activated by

Answer 23

AMP and fructose-1,6-bisphosphate

Question 24

where is hexokinase found at what is its functions

Answer 24

• normal energy requiring tissue eg. muscles
• low Km so is saturated at low glucose levels
• regulated by G6P negative feedback

Question 25

describe the Km, regulation and function

Answer 25

- Km is higher so high capacity of glucose - no feedback from G6P - glucose sensing in the pancreas and reduce glycolysis in the liver for glycogen synthesis

Question 26

what does insulin do to glycolysis

Answer 26

increases glycolysis buy inducing hexokinase, phopshofructokinase-1 and pyruvate kinase - stimulates glucose uptake in blood

Question 27

what does the muscle, liver and adipose do when there is insulin released

Answer 27

muscle and liver - converts glucose to glycogen liver - decrease glyconeogenesis adipose - increases fat synthesis to act on hypothalamus to decrease appetite

Question 28

what does the release of glucagon do to glycolysis

Answer 28

- decrease glycolysis - represses hexokinase, phosphofructokinase-1 and pyruvate kinase

Question 29

what does the release of glucagon do to the muscle and liver

Answer 29

muscle and liver - stimulates glycogen breakdown liver - stimulates gluconoegenesis

Question 30

what happens in aerobic conditions to NAD+ recovery

Answer 30

- NADH not oxidised in electron transport chain - NADH build up - pyruvate reduced to lactate by lactate dehydrogenase - NAD+ used for glycolysis

Question 31

describe the cori cycle

Answer 31

1) glycolysis in the muscles coverts glucose to lactate 2) lactate is transported to the liver via blood 3) gluconeogenesis in liver reforms glucose from lactate 4) glucose transported back to muscles via blood

Question 32

when does the cori cycle take place

Answer 32

- under anaerobic conditions - liver resupplies muscles with glucose and maintains normal blood glucose levels

Question 33

what is lactic acidosis and what are the symptoms

Answer 33

- lactic acid build up in blood stream >4mM - symptoms - nausea, vomiting, weakness

Question 34

what is lactic acidosis causes by

Answer 34

- decrease O2 delivery to tissue - decrease lactate clearance - liver disease and sepsis - increase lactate production - cancer

Question 35

describe the manose cycle

Answer 35

- mannose ---> mannose-6- phosphate - hexokinase and ATP - mannose-6-phosphate --> fructose-6-phosphate - phopshomannose isomerase - glycolysis continues

Question 36

what cause lactose intolerance

Answer 36

- no lactase - increased osmotic pressure - bacterial fermentation - causes diarrhoea

Question 37

what causes fructose intolerance

Answer 37

- no GLUT5 carrier protein - increases osmotic pressure - diarrhoea

Question 38

what are the two stages of the pentose shunt

Answer 38

- oxidative phase - non-oxidative phase

Question 39

what does the pentose shunt produce

Answer 39

- NADPH - ribose-5-phosphate - fructose-6-phospahte

Question 40

what is the oxidative phase of the pentose shunt dependent on

Answer 40

- availability of NADP+

Question 41

what is the non oxidative phase of the pentose shunt dependent on

Answer 41

- availability of substrates

Question 42

when is the non oxidative phase of the pentose shunt active

Answer 42

- when ribose-5-phosphate is required more than NADP

Question 43

when is the oxidative phase of the pentose shunt active

Answer 43

- when ribose-5-phosphate and NDPH are required equally

Question 44

what occurs when NADPH is required more than ribose-5-phosphate in the pentose shunt

Answer 44

- fructose-6-phosphate and glyceraldehyde-3-phosphate are converted back into glucose-6-phosphate by phosphoglucose isomerase and glyceraldehyde phosphate dehydrogenase - glucose may be converted into pyruvate

Question 45

what are the causes, symptoms and triggers for 6-GPD deficiency

Answer 45

causes - X-linked recessive, major cause of haemolytic anaemia symptoms - dark urine, fatigue, painless, rapid heart rate, shortness of breathe, jaundice triggers - foods, medicine, bacterial or virus infections

Question 46

what is used to measure vitamin B - thiamine levels

Answer 46

- erythrocyte transketolase assay

Question 47

what enzymes is vitamin B1 - thiamine used in

Answer 47

- pyruvate dehydrogenase - transketolase activity