Glycolysis

Question 1

what is the major energy source for most organisms

Answer 1

glucose

Question 2

is glycolysis anaerobic or aerobic?

Answer 2

anaerobic

Question 3

where does glycolysis occur?

Answer 3

in the cytosol

Question 4

what are the 2 phases?

Answer 4

1. preparatory phase (uses ATP)

2. payoff phase (produces ATP and NADH)

Question 5

overall glycolysis reaction?

Answer 5

glucose + 2ADP + 2NAD+ + 2Pi –> 2pyruvate + 2ATP + 2NADH + 2H20

Question 6

What is the net output of glycolysis?

Answer 6

2pryuvate
2ATP
2NADH
2H20

Question 7

what is the input of glycolysis?

Answer 7

glucose
2adp
2nad+
2Pi

Question 8

what percentage of energy capture is in glycolysis?

Answer 8

5% (because no oxygen)

Question 9

how much energy is in the complete oxidation of glucose?

Answer 9

28040kJ/mol

deltaGprimenaught = -2840kJ/mol

Question 10

final products of the preparatory phase?

Answer 10

2 dihydroxyacetone phosphate + 2 Glyceraldehyde-3-phosphate + 2 ADP

Question 11

final products of the payoff phase?

Answer 11

2 pyruvates + 4ATP + 2NADH + 2H+

Question 12

what is normal blood glucose in blood?

Answer 12

4-5mM

Question 13

what inhibits hexokinase?

Answer 13

high levels of G6P

Question 14

how many ATP are used in prep phase?

Answer 14

2

Question 15

how many ATP are produced in payoff phase?

Answer 15

4

Question 16

how many NADH + H+ are produced in payoff?

Answer 16

2

Question 17

what is the goal of the preparatory phase?

Answer 17

to make the stable glucose molecule unstable

this allows breaking c-c bonds

Question 18

how much energy is in a c-c bond?

Answer 18

approx 400kJ/mol

Question 19

which are the two ATP forming reactions?

Answer 19

1,3-bisphosphoglycerate–>3-phosphoglycerate
enzyme:phosphoglycerate kinase

and

phosphoenolpyruvate–>pyruvate
enzyme:pyruvate kinase

Question 20

Describe the reaction of:
glucose –>G6P

Describe the inhibition of hexokinase

Answer 20

glucose –> glucose-6-phosphate by hexokinase

produces 1 ADP

negative deltaG (spontaneous)

inhibited by high levels of G6P (negative feedback)

Glucokinase: a glucose sensor in liver,brain,pancreas,intestine. Regulated by Glucokinase regulatory protein (GKRP).

low glucose –> GKRP binds with GK
high glucose–>fructose-6-phosphade production –> F6P binds to GKRP –> releases GK back to the cytosol

Question 21

enzyme that catalyzes 2nd step G6P –> F6P

Answer 21

phosphohexose isomerase

Question 22

describe the 3rd step

Answer 22

enyme: phosphofructokinase-1

reaction itself is not favourable, but is favourable when coupled with ATP hydrolysis

ATP is an allosteric regulator of PFK1: ATP binds to PFK1 –> reduces affinity for F6P –>reduces enzyme activity

Question 23

Is ADP and AMP allosteric inhibitors or activators in the 3rd step?

Answer 23

activators

ADP and AMP signals lack of ATP

Question 24

is ATP an allosteric inhibitor or activator with hexokinase?

Answer 24

inhibitor

Question 25

will the 3rd step (phosphofructokinas-1) be faster when [ATP] is low or high?

Answer 25

faster when [ATP] is low | slower when high

Question 26

which enzyme is inhibited by ATP?

Answer 26

phosphofructokase-1