Glycolysis

Question 1

Purpose of glycolysis

Answer 1

Universal pathway in cytoplasm of All cells to produce ATP and 3/6C intermediates

• can be aerobic or anaerobic

Question 2

Anaerobic glycolysis

Answer 2

Pyruvate is reduced to lactate via oxidation of NADH

(Converts glucose to 2 lactate)

Very minimal ATP production (2)

ONLY pathway of ATP production in the absence of O2

Question 3

Priming stage of glucolysis

Answer 3

Glucose -> fructose 1,6 biphosphate

Enzyme hexokinase phosphorylate glucose -> G6P

Enzyme phosphohexonse isomerase changes G6P - > F6P

Enzyme phosphofructo Kinase 1 phosphorylate F6P -> F 1,6BP

Question 4

Enzymes involved in irreversible steps of glycolysis

Answer 4

Hexokinase

Phosphofructo kinase 1

Pyruvate kinase

• if any of these enzymes are deactivated in anyway, glycolysis DOES NOT occur

Question 5

Cleavage stage of glycolysis

Answer 5

Enzyme aldolase cleaves F 1,6BP -> GA3P and DHAP

• triode phosphate isomerase transforms DHAP into GA3P forming 2 G3P molecules
  ( done because only GA3P can be used in the oxidative stage)

Question 6

Aerobic glycolysis

Answer 6

Converts pyruvate to acetyl CoA

Large-scale ATP via oxidative phosphorylation

Question 7

Molecules that can be catabolized by glycolysis pathway

Answer 7

Glucose, fructose, galactose and ribose

Question 8

Priming intermediates

Answer 8

Glucose ->

G6-P ->

F6-P ->

F1,6-BP

Question 9

Hexokinase or Glucokinase

HK/GK

Answer 9

Uses ATP to phosphorylate Glucose -> G6-P

-Irreversible reaction

Question 10

Phosphofructo kinase 1 (PFK1)

Answer 10

Uses ATP to phosphorylate F6-P
-> F1,6-BP

• irreversible reaction

Question 11

Cleavage intermediates

Answer 11

F1,6-BP

GA3-P

DHAP

Question 12

Aldolase

Answer 12

Cleaves F1,6-BP into GA 3-P & DHAP

Question 13

Triose phosphate isomerase

Answer 13

Converts DHAP into GA 3-P

• does this because DHAP is not able to be oxidized in step 3

Question 14

Oxidation and ATP production intermediates

Answer 14

GA-3P

PEP

Pyruvate

Question 15

Pyruvate Kinase

Answer 15

Converts PEP into pyruvate

-irreversible reaction

Question 16

GA-3P produces what in glycolysis?

Answer 16

2 NADH

2 ATP

Question 17

PEP produces what in oxidation when converted to pyruvate?

Answer 17

2 ATP

Question 18

Net products for glycolysis

Answer 18

2 pyruvate

2 NADH

2 ATP
4 (produced in step 3) - 2 (consumed in step 1)

Question 19

Anaerobic glycolysis net products

Answer 19

2 ATP

2 NAD+ (used in future glycolysis reactions)

Question 20

Enzyme used in anaerobic glycolysis that reduces pyruvate to lactate

Answer 20

Lactate dehydrogenase

• oxidizes NADH to NAD+

Question 21

Total ATP produced in aerobic glycolysis

Answer 21

30-32

Question 22

What cells undergo anaerobic glycolysis

Answer 22

Cells without mitochondria

Cells experiencing hypoxia

Question 23

Why cant aerobic glycolysis occur in the cytoplasm only?

Answer 23

NADH and NAD+ are impermeable to the inner membrane of mitochondria.

• in order to regenerate NADH molecules, two shuttle systems are used to move electrons into the mitochondrial matrix

Question 24

Two different electron shuttle systems used in aerobic glycolysis

Answer 24

1) electrons use FADH2 as an electron carrier

2) electrons use already produced NADH as electron carriers (3-5 ATP producers)