Stage 1 - Glycolysis

Question 1

Where does glycolysis occur?

Answer 1

Cytoplasm

Question 2

What does the complete oxidation of glucose produce?

Answer 2

CO2 and H2O

Question 3

What is the end product of glycolysis?

Answer 3

Pyruvate

Question 4

What does pyruvate get oxidized to in aerobic setting?

Answer 4

CO2

Question 5

What does pyruvate get oxidized to in anaerobic setting?

Answer 5

ethanol or lactate

Question 6

Why does glucose need a transporter?

Answer 6

It is highly polar

Question 7

What catalyzes glucose import?

Answer 7

GLUTs

Question 8

What does insulin do? What happens in diabetes?

Answer 8

stimulate GLUT mediated glucose uptake
blood glucose isn’t taken up to cells adequately

Question 9

What are the first 5 reactions in glycolysis?

Answer 9

Prep phase
ATP is used

Question 10

What are the second 5 reactions in glycolysis?

Answer 10

Payoff phase
ATP is produced (net generation of ATP)

Question 11

Glycolysis first reaction
cofactor
enzyme
what happens

Answer 11

Glucose->glucose 6 phosphate
ATP->ADP
hexokinase
*irreversible
phosphorylation of glucose

Question 12

Glycolysis second reaction
cofactor
enzyme
what happens

Answer 12

glucose 6 phosphate->fructose 6 phosphate (ketose/hemiketal)
none
phosphohexose isomerase
glucose is isomerized into fructose

Question 13

Glycolysis third reaction
cofactor
enzyme
what happens

Answer 13

fructose 6 phosphate->fructose 1,6-bisphosphate
ATP->ADP
PFK-1
2nd phosphorylation (priming)

Question 14

Glycolysis fourth reaction
cofactor
enzyme
what happens

Answer 14

fructose 1,6-bisphosphate->dihydroxyacetone phosphate
none
aldose
The 6C fructose is split into 2 3C units
DHAP is immediately hydrolyzed into G3P

Question 15

Glycolysis fifth reaction
cofactor
enzyme
what happens

Answer 15

dihydroxyacetone phosphate->G3P
none
triose phosphate isomerase
interconversion of triose phosphate

Question 16

Glycolysis sixth reaction
cofactor
enzyme
what happens

Answer 16

G3P->1,3-bisphosphoglycerate
NAD+->NADH+H+
G3P dehydrogenase
Energy key of glycolysis - the G3P is bound to cys residue on G3P dehydrogenase and oxidized to enzyme bound thioester which is attacked by Pi

Question 17

Glycolysis seventh reaction
cofactor
enzyme
what happens

Answer 17

1,3-bisphosphoglycerate->3-phosphoglycerate
ADP->ATP
phosphoglycerate kinase
substrate level phosphorylation, 2 ATP per 1 glucose, the free E of anhydride bond is recovered in form of ATP

Question 18

Glycolysis eighth reaction
cofactor
enzyme
what happens

Answer 18

3-phosphoglycerate->2-phosphoglycerate
none
phosphoglycerate mutase
a functional group is shunted between 2- and 3- OH groups

Question 19

Glycolysis ninth reaction
cofactor
enzyme
what happens

Answer 19

2-phosphoglycerate->phosphoenolpyruvate
H2O leaves
enolase
eliminates H2O to create double bond
creation of the second high energy molecule

Question 20

Glycolysis tenth reaction
cofactor
enzyme
what happens

Answer 20

phosphoenolpyruvate->pyruvate (enol form)
ADP->ATP
pyruvate kinase
quickly changes to keto form to decrease concentration of reaction product

Question 21

Glycolysis tenth reaction pt 2
cofactor
enzyme
what happens

Answer 21

pyruvate (enol form)->pyruvate (keto form)
none
tautomerization
gives rise to large and negative delta G

Question 22

What does the Cori cycle do?

Answer 22

Recovery of strenous activity - uses lactic acid produced from glycolysis and moves it to the liver via the blood to turn into glucose which is returned to muscles.

Question 23

What does alcoholic condensation do? What is the ultimate electron acceptor?

Answer 23

Yeast converts pyruvate to ethanol + CO2. Not in humans. NAD+ is regenerated allowing glycolysis to continue.
acetaldehyde

Question 24

What happens to pyruvate after glycolysis in aerobic conditions?

Answer 24

ETC reoxidizes NADH with O2 and pyruvate will be oxidized to CO2

Question 25

What transports pyruvate into mitochondria?

Answer 25

transporter protein

Question 26

Transporter protein - What does the malate aspartate shuttle transport? What enzyme helps?

Answer 26

Transfers NADH reducing equivalents from cytoplasm to mitochondrial matrix. Malate dehydrogenase

Question 27

Transporter protein - G3P shuttle

Answer 27

Uses FAD to oxidize G3P, resulting in FADH2

Question 28

What 5 coenzymes does the pyruvate dehydrogenase complex need?

Answer 28

NAD+, FAD, CoA, TPP, lipotate

Question 29

What is the reaction that connects glycolysis to the citric acid cycle?

Answer 29

Pyruvate dehydrogenase complex

Question 30

Write a balanced equation for the Pyruvate dehydrogenase complex. What are the cofactors?

Answer 30

Pyruvate --> Acetyl CoA NAD+->NADH +H+ CoASH-->

Question 31

People with beriberi, a disease caused by thiamine (vitamin B1) deficiency, have elevated levels of blood pyruvate. How is this effect related to a deficiency of thiamine?

Answer 31

The lack of thiamine leads to thiamine pyrophosphate not being utilized from the lack of the enzyme thiamine pyrophosphate. The carboxylation of a-keto acids can not occur leading to an elevated blood pyruvate.