Final: glycolysis

Question 1

glycolysis overview

Answer 1

glucose (6 carbon sugar) is broken down into 2 pyruvates (3 carbons) and ATP (energy)

Question 2

where does glycolysis happen?

Answer 2

cytoplasm of ALL CELLS

Question 3

does glycolysis need oxygen?

Answer 3

NO

Question 4

2 phases of glycolysis

Answer 4

energy consuming phase (uses ATP)

energy producing phase (produces ATP and reduced NADH)

Question 5

what can NADH be used for?

Answer 5

creating ATP

Question 6

after eating, glucose must be moved from where to where?

Answer 6

from the small intestine to the bloodstream
uses GLUTs (glucose transporters)

Question 7

where are GLUTs located?

Answer 7

cell membrane

Question 8

GLUT2

Answer 8

liver and pancreas

more responsive to glucose in the presence of insulin

Question 9

Glycolysis step 1

Answer 9

Glucose to Glucose-6-phosphate

enzyme: hexokinase/glucokinase phosphorylates glucose at C6
keeps glucose inside cell!

Question 10

hexokinase vs glucokinase

Answer 10

hexokinase: found in all cells
glucokinase: induced by insulin
- found in liver and pancreas

Question 11

rate determining step of glycolysis?

Answer 11

Phosphofructokinase 1 (PFK1)

Question 12

Glycolysis step 3 (rate-determining)

Answer 12

fructose 6-phosphate to fructose 1,6-bisphosphate

enzyme: phosphofructokinase-1 (PFK1) adds phosphate to C1 on fructose

uses ATP as phosphate source
-2 ATP!

Question 13

what regulates PFK1?

Answer 13

PFK2!

PFK2 phosphorylates fructose-6-phosphate at C2, making fructose 2,6-bisphosphate

Question 14

PFK2 regulation well fed

Answer 14

well fed = increase in insulin = increase in PFK2 = more fructose-2,6-bisphosphate = more PFK1 = more glucose to more energy

Question 15

PFK2 regulation fasting

Answer 15

fasting = increase in glucagon = inhibits PFK2 = less fructose-2,6-bisphosphate = inhibits PFK1 = less glycolysis

Question 16

what else controls PFK1?

Answer 16

high energy state = lots of ATP and citrate = inhibition of PFK1

we have enough energy, don’t need to make more

Question 17

difference between G3P and DHAP

Answer 17

only G3P can go down glycolysis pathway

Question 18

what happens to NADH from G3P dehydrogenase rxn?

Answer 18

2 NADH go onto electron transport chain and go on to make 3 ATP each

Question 19

where does pyruvate go after glycolysis?

Answer 19

it can go to the mitochondria where it has access to oxygen and can undergo the Krebs cycle and citric acid cycle
END UP WITH 30-32 ATPs

Question 20

where does pyruvate go in a low oxygen state?

Answer 20

low oxygen = exercising skeletal muscle cells or red blood cells with no mitochondria

lactate dehydrogenase takes an H from NADH and gives it to pyruvate
makes lactate and NAD+

Question 21

why do we need NAD+?

Answer 21

to work with G3P dehydrogenase and keep glycolysis going