NME 2.27

Question 1

what is glycolysis?

Answer 1

breakdown of glucose

Question 2

what is the glucose transporters in red blood cells?

Answer 2

• GLUT1

Question 3

what is the glucose transporters in liver or kidney?

Answer 3

GLUT2

Question 4

what is the glucose transporters in neurones?

Answer 4

GLUT3

Question 5

what is the glucose transporters in adipose tissue and muscles

Answer 5

GLUT4

Question 6

what is the glucose transporters in intestine?

Answer 6

SGLT

Question 7

what is the role of glycolysis?

Answer 7

• oxidation of glucose to generate ATP

- providing building blocks for anabolic reactions

Question 8

outline the process of stage 1 aerobic glycolysis

Answer 8

• glucose –> glucose 6 phosphate –> fructose 6 phosphate –> fructose 1,6 bisphosphate –> dihydroxyacetone phosphate (DHAP) –> glyceraldehyde 3-phosphate

Question 9

outline the process of stage 2 aerobic glycolysis?

Answer 9

glyceraldehyde 3 phosphate –> 1,3 bisphosphoglycerate –> 3-phosphateglycerate –> 2-phosphoglycerate –> phosphoenolpyruvate
–> pyruvate

Question 10

what is the difference between aerobic and anaerobic glycolysis?

Answer 10

for anaerobic, the pryuvate will form lactate

Question 11

what does the conversion of pryuvate to lactate uses?

Answer 11

NADH

Question 12

what are the three enzymes that regulate glycolysis?

Answer 12

• glucokinase
• phosphofructokinase
• pyruvate kinase

Question 13

is glucokinase or hexokinase in the liver?

Answer 13

glucokinase

Question 14

what does glucokinase do?

Answer 14

convert glucose to glucose 6-P

Question 15

what does phosphofructokinase do?

Answer 15

convert fructose 6-P to fructose 1,6-bis-P

Question 16

what does pyruvate kinase do?

Answer 16

convert phosphoenolpyruvate to pyruvate

Question 17

what is the difference between glucokinase and hexokinase?

Answer 17

• glucokinase is for liver while hexokinase is for tissues
• glucokinase has low affinity for glucose while hexokinase has high affinity for glucose
• glucokinase has high Vmax glucose while hexokinase has low Vmax glucose
• glucokinase is not inhibited by G6P while hexokinase is inhibited by G6P

Question 18

hexokinase or glucokinase functions better at low concentration of glucose?

Answer 18

• hexokinase function efficiently at low concentration of glucose

Question 19

which is the most important regulatory enzyme of glycolysis?

Answer 19

• phosphofructokinase

Question 20

describe phosphofructokinase?

Answer 20

• rate limited step
• allosterically inhibited by ATP
• allosterically stimulated by AMP

Question 21

which one is the most potent allosteric activator of PFK1?

Answer 21

• fructose 2,6-bisphosphate even when ATP levels are high

Question 22

describe the liver in well fed state?

Answer 22

• increase in insulin
• decrease in glucagon
• increase in fructose 2,6-biphosphate
• increase in glycolysis

Question 23

describe the liver in fasting state?

Answer 23

• decrease in insulin
• increase in glucagon
• decrease in fructose 2,6-biphosphate
• reduce glycolysis

Question 24

what activates pyruvate kinase?

Answer 24

• fructose-1,6-BP

Question 25

describe relationship of PFK1 and pyruvate kinase?

Answer 25

- their activities are linked | - there is forward feeding

Question 26

what is phosphorylation?

Answer 26

- when a phosphate is added

Question 27

what enzyme adds phosphate to protein?

Answer 27

kinase

Question 28

what enzyme removes phosphate from a protein?

Answer 28

phosphatase

Question 29

describe fructose metabolism

Answer 29

- fructokinase will change fructose to fructose-1-phosphate | - then aldolase will change fructose-1-phosphate to glyceraldehyde or dihydroxyacetone phosphate (DHAP)

Question 30

what does lack in fructose cause?

Answer 30

- essential fructosoria | - accumulation of fructose in urine

Question 31

what does lack of aldolase B cause?

Answer 31

hereditary fructose intolerance