Sugar Metabolism

Question 1

major carbohydrates

Answer 1

sucrose
lactose
starch
high-fructose corn syrup

Question 2

sucrose

Answer 2

glucose - fructose

Question 3

lactose

Answer 3

galactose - glucose

Question 4

starch

Answer 4

polymeric form of glucose

Question 5

high -fructose corn syrup is __% fructose?

Answer 5

55%

Question 6

Glycolysis is broken down from a __ carbon sugar to ________

Answer 6

6-carbon sugar to 2 pyruvate

Question 7

Glycolysis occurs in the

Answer 7

cytoplasm

Question 8

Can glycolysis occur when oxygen levels are low?

Answer 8

yes

Question 9

energy consuming phase _______ ATP and energy producing phase ______ ATP

Answer 9

requires, produces

Question 10

How does glucose go from the bloodstream to the cell membranes?

Answer 10

through glucose transporters like GLUT (are in the cell membrane)

Question 11

What prevents glucose from exiting cell?

Answer 11

the enzyme kinase

Question 12

What changes the shape of glucose?

Answer 12

when kinase adds a phosphate group (comes from breakdown of ATP to ADP)
this then does not allow it to diffuse

Question 13

What is the name of 2 Kinase and what do they do?

Answer 13

hexokinase & glucokinase

- they add a phosphate group to the 6 carbon end of a glucose molecule

Question 14

What is the difference between hexokinase and glucokinase?

Answer 14

hexokinase is found in all cells

glucokinase is induced by the presence of insulin ( found in liver and beta cells of pancrease)

Question 15

Is the third step in glycolysis irreversible or reversible?

Answer 15

irreversible

Question 16

What steps of glycolysis are irreversible?

Answer 16

1,3,10

Question 17

What is the rate limiting step? What enzyme?

Answer 17

3rd step, with the enzyme PFK1

Question 18

When blood glucose goes up, insulin goes up, and this makes more _____ which makes more

Answer 18

PFK2, PFK1

Question 19

When blood glucose go back to normal, pancreas secretes _____

Answer 19

glucagon

Question 20

Glucagon inhibits

Answer 20

PFK2

Question 21

What happens when PFK2 is inhibited by glucagon?

Answer 21

It slows down the rate of glycolysis because it will not be making fructose 2,6-bisphosphate which makes more PFK1. So less PFK1 = lower rate of glycolysis

Question 22

How many G3P molecules per glucose molecules?

Answer 22

2

Question 23

each G3P is converted to __________ by ________.

Answer 23

1,-3-Bisphosphoglycerate (1,3-BPG) by GAP dehydrogenase

Question 24

What upregulates pyruvate kinase?

Answer 24

fructose-1,6-bisphosphate

- feed-forward regulation

Question 25

What downregulates pyruvate kinase?

Answer 25

high ATP or alanine

- alanine comes from skeletal muscle breakdown during fasting

Question 26

High levels of alanine signify that the body needs to

Answer 26

make more glucose not break it down in glycolysis
- since alanine is released when skeletal muscle is being broken down bc of fasting (hence the body is looking for glucose) you do not want to waste glucose by breaking it down during glycolosis

Question 27

Is glycolysis aerobic or anaerobic?

Answer 27

anaerobic

Question 28

What cells have limited oxygen?

Answer 28

RBC (bc no mitochondria), exercising skeletal muscle cell

Question 29

glycolosys makes net

Answer 29

2 ATP

2 NADH

Question 30

1 NADH makes __ ATP in the mitochondria

Answer 30

3

Question 31

1 FAD can make __ ATP

Answer 31

2

Question 32

1 glucose makes __ Net ATP

Answer 32

38