Glycolysis

Question 1

Carbohydrate digestion locations

Answer 1

mouth - salivary amylase (inactivated in the stomach)
intestines - pancreatic amylase breaks down into monosaccharides
active transport in bloodstream

Question 2

glucose as a precursor
pathways

Answer 2

amino acids, membrane lipids, nucleotides, cofactors in metabolism

structural polymer synthesis, storage, oxidation via glycolysis, oxidation via pentose phosphate pathway

Question 3

mutases function

Answer 3

catalyze migration of functional groups

Question 4

cell types for which glucose is sole source of energy

Answer 4

erythrocytes, brain, sperm, renal medulla

Question 5

ATP produced and consumed in glycolysis

Answer 5

2 consumed in prep phase
4 produced in payoff phase (2 per G3P)

Question 6

hexokinase isoforms

Answer 6

I-IV, same function different forms

Question 7

Step 1 Glycolysis

Answer 7

Glucose –> Glucose-6-phosphate
Enzyme: hexokinase
Cofactors: Mg2+, ATP
Function: trap glucose in cell, reduce intracellular [glucose],
Reversibility: irreversible

Question 8

Step 2 Glycolysis

Answer 8

Glucose-6-phosphate –> fructose-6-phosphate
Enzyme: Phosphohexose isomerase
Cofactors: Mg2+
Function: facilitates next step (easier phosphorylation and cleavage)
Reversibility: reversible

Question 9

Step 3 Glycolysis

Answer 9

Fructose-6-phosphate –> fructose 1,6-bisphosphate
Enzyme: phosphofructokinase-1 (PFK-1)
Cofactors: Mg2+ and ATP
Function: creates symmetrical molecule, first committed step of glycolysis
Reversibility: irreversible

Question 10

Step 4 Glycolysis

Answer 10

Fructose 1,6-bisphosphate –> glyceraldehyde-3-phosphate and dihydroxyacetone phosphate
Enzyme: aldolase
Cofactors: none
Function: creating 2 high energy phosphate sugars
Reversibility: reversible

Question 11

Step 5 Glycolysis

Answer 11

Dihydroxyacetone Phosphate –> Glyceraldehyde-3-phosphate
Enzyme: Triose phosphate isomerase
Cofactors: none
Function: converting ketose to aldehyde, completes prep phase
Reversibility: reversible

Question 12

Step 6 Glycolysis

Answer 12

Glyceraldehyde-3-phosphate –> 1,3-bisphosphoglycerate + NADH + H+
Enzyme: glyceraldehyde-3-phosphate dehydrogenase (GAPDH)
Cofactors: NAD+, Pi
Function: oxidation, adding of Pi
Reversibility: reversible

Question 13

Step 7 Glycolysis

Answer 13

1,3-bisphosphoglycerate –> 3-phosphoglycerate
Enzyme: phosphoglycerate kinase
Cofactors: Mg2+, ADP
Function: substrate levels phosphorylation
Reversibility: reversible

Question 14

Step 8 Glycolysis

Answer 14

3-Phosphoglycerate –> 2-phosphoglycerate
Enzyme: phosphoglycerate mutase
Cofactors: Mg2+
Function: phosphohistidine phosphate swap
Reversibility: reversible

Question 15

Step 9 Glycolysis

Answer 15

2-phosphoglycerate –> phosphoenolpyruvate + H2O
Enzyme: enolase
Cofactors: none
Function: generation of high energy phosphate compound
Reversibility: reversible

Question 16

Step 10 Glycolysis

Answer 16

Phosphoenolpyruvate –> pyruvate
Enzyme: pyruvate kinase
Cofactors: Mg2+, K+, ADP
Function: substrate level phosphorylation
Reversibility: irreversible

Question 17

Net yield glycolysis equation

Answer 17

1 Glucose + 2 ATP + 2 NAD+ + 4ADP + 2Pi = 2 Pyruvate + 2 ADP + 2 NADH + 2H+ + 4 ATP + 2H2O

Question 18

fates of 2 pyruvate

Answer 18

2 Lactate (anaerobic)
2 Ethanol + CO2 (anaerobic)
2 acetyl coA + 2CO2 –> 4 CO2 + 4 H2O (aerobic)

Question 19

Cori cycle

Answer 19

Pyruvate –> L-lactate
anaerobic, lactate dehydrogenase
produces NAD+ for glycolysis to continue
Lactate converted to glucose in liver
ex. erythrocytes, vigorously contracting muscle