Glycolysis

Question 1

Once in the cell, glucose is converted to ___.

Answer 1

glucose-6-phosphate

Question 2

The conversion of glu –> G6P is key because it involves?

Answer 2

the investment of an ATP

Question 3

The 2nd phosphate molecule is added to G6P by the enzyme ____.

Answer 3

phospho-fructo-kinase (PFK)

Question 4

What does phospho-fructo-kinase (PFK) do?

Answer 4

adds a phosphate to G6P to form fructose-1,6-bisphosphate

Question 5

What is the rate-limiting step in glycolysis?

Answer 5

PFK adding a phosphate to F6P to form fructose-1,6-bisphosphate

Question 6

What is the end product of glycolysis?

Answer 6

pyruvate

Question 7

In the presence of O2, pyruvate will enter the ____ in the cell to begin what process?

Answer 7

mitochondria; TCA cycle

Question 8

In the mitochondria, pyruvate is converted into the molecule _____

Answer 8

acetyl-CoA

Question 9

Why is the formation of lactate important?

Answer 9

it regenerates NAD and allows glycolysis to continue

Question 10

What molecule converts glucose to G6P?

Answer 10

hexokinase or glucokinase

Question 11

Which glucose transporter is insulin dependent?

Answer 11

glut4

Question 12

Which glucose transporter is NOT insulin dependent?

Answer 12

glut2

Question 13

Where in the cell does glycolysis occur?

Answer 13

the cytoplasm

Question 14

Hexokinase or glucokinase?

not very selective

Answer 14

hexokinase

Question 15

Hexokinase or glucokinase?

present in all cells

Answer 15

hexokinase

Question 16

Hexokinase or glucokinase?

low Km for sugars

Answer 16

hexokinase

Question 17

Hexokinase or glucokinase?

inhibited by glucose-6-P

Answer 17

hexokinase

Question 18

Hexokinase or glucokinase?

selective for glucose

Answer 18

glucokinase

Question 19

Hexokinase or glucokinase?

in liver and pancreatic beta cells only

Answer 19

glucokinase

Question 20

Hexokinase or glucokinase?

high Km for glucose

Answer 20

glucokinase

Question 21

Hexokinase or glucokinase?

inhibited by fructose-6-P

Answer 21

glucokinase

Question 22

What is the normal blood glucose conc. in mM? How do you convert that to mg/dl?

Answer 22

4-5mM (x18 = 72-90mg/dl)

Question 23

fructose-6-P + ATP –> ?

Answer 23

fructose-1,6-bisphosphate + ADP

Question 24

What inhibits PFK?

Answer 24

ATP and citrate

Question 25

What stimulates PFK?

Answer 25

AMP

Question 26

PFK2 is unique in the liver in that it is active when _____ and inactive if _____.

Answer 26

active = dephosphorylated
inactive = phosphorylated

Question 27

What do high levels of insulin and low levels of glucagon do to for glycolysis?

Answer 27

increase it

Question 28

What else is created in the same step when the two 3-C compounds are formed in glycolysis?

Answer 28

NADH

Question 29

What else is created in the first substrate-level phosphorylation step of glycolysis?

Answer 29

ATP

Question 30

What enzyme in glycolysis catalyzes the 2nd substrate-level phosphorylation?

Answer 30

pyruvate kinase

Question 31

What inhibits pyruvate kinase?

Answer 31

ATP, alanine, PKA

Question 32

What stimulates pyruvate kinase?

Answer 32

fructose-1,6-bisphosphate

Question 33

____ and _____ enzyme deficiencies of glycolysis can cause hemolytic anemia.

Answer 33

Pyruvate kinase; G6PD

Question 34

Glucagon often results in _______ of key enzymes.

Answer 34

phosphorylation

Question 35

______ often results in phosphorylation of key enzymes.

Answer 35

Glucagon

Question 36

If NAD+ is not regenerated, _____ will not be oxidized and glycolysis will stop.

Answer 36

glyceraldehyde-3-phosphate