Glycolysis and Pyruvate Dehydrogenase

Question 1

Maltase cleaves maltose to yield

Answer 1

2 glucoses

Question 2

Isomaltase cleaves isomaltose to yield

Answer 2

2 glucoses

Question 3

Lactase cleaves lactose to yield

Answer 3

glucose and galactose

Question 4

Sucrase cleaves sucrose to yield

Answer 4

glucose and fructose

Question 5

Reason why humans cannot harness energy from plants

Answer 5

Cellulose is BETA-1,4 glycosidic bond, not Alpha

Question 6

Normal glucose concentration in peripheral blood

Answer 6

4-6 mM or 70-110 mg/dL

Question 7

High affinity glucose transporters of the brain

Answer 7

GLUT 1 and GLUT 3

Question 8

Low affinity glucose transporter of the liver (excessive glucose intake needed)

Answer 8

GLUT 2

Question 9

Glucose transporter of the pancreas

Answer 9

GLUT 2

Question 10

Tissues with GLUT 4, a transporter stimulated by exercise, are

Answer 10

Adipose and muscle

Question 11

Rate limiting enzyme in Glycolysis

Answer 11

Phosphofructokinase-1

Question 12

Co-factor of the first step in Glycolysis

Answer 12

Mg is needed by Glucokinase (liver and pancreatic beta islet cells) and Hexokinase (other tissue)

Question 13

First half of glycolysis involves the synthesis of 2 triose phosphates namely

Answer 13

Glyceraldehyde-3P and Dihydroxyacetone (DHAP)

Question 14

Insulin indirectly activates glycolysis by activating which enzyme/intermediate

Answer 14

PFK-2, Fructose 2,6 biphosphate

Question 15

Deficiency in this glycolytic enzyme leads to hemolytic anemia, increased bisphosphoglycerate (BPG), but no Heinz bodies (2nd most common genetic deficiency that causes hemolytic anemia)

Answer 15

Pyruvate kinase deficiency (G6PDH deficiency is the most common)

Question 16

Low Km = ___ affinity

Answer 16

high

Question 17

ATP and citrate (activates/inhibits?) PFK-2?

Answer 17

inhibits

Question 18

Type of reaction in which ADP is directly phosphorylated to ATP using a high-energy intermediate

Answer 18

substrate-level phosphorylation (vs oxidative phosphorylation)

Question 19

High energy substrate of pyruvate kinase for the 2nd substrate level phosphorylation in glycolysis

Answer 19

Phosphoenolpyruvate (PEP)

Question 20

Enzyme responsible for the reoxidation/recirculation of NADH back to the 1st substrate level phosphorylation care of glyceraldehyde 3P DH

Answer 20

Lactate dehydrogenase

Question 21

3 enzymes involved in the irreversible steps in glycolysis

Answer 21

Glucokinase/hexokinase, PFK-1, Pyruvate kinase

Question 22

Cytoplasmic NADH oxidized using the malate shuttle produces a mitochondrial NADH and yields how many ATP by oxidative phosphorylation

Answer 22

3 ATP

Question 23

Cytoplasmic NADH oxidized using the glycerol phosphate shuttle produces a mitochondrial NADH and yields how many ATP by oxidative phosphorylation

Answer 23

2 ATP

Question 24

Binding of this glycolytic intermediate to beta-chains of hemoglobin A decreases the latter’s affinity to oxygen (rightward shift in curve), commonly happening as an adaptation to high altitudes and pyruvate kinase deficiency

Answer 24

2,3 BPG

Question 25

Diarrhea, bloating, cramps after milk ingestion

Answer 25

Lactase deficiency

Question 26

Enzyme responsible for Galactitol accumulation and subsequent cataract formation in Galactosemia

Answer 26

Aldose reductase

Question 27

Deficient enzymes in Galactosemia

Answer 27

Galactokinase and/or Gal 1-P uridyltransferase

Question 28

Cataracts in early life, vomiting and diarrhea after lactose ingestion, lethargy, liver damage, hyperbilirubinemia, mental retardation. What enzyme deficiency?

Answer 28

Gal 1-P uridyltransferase deficiency (converts Gal-1-P to Gluc-1-P for subsequent entry in Glycolysis)

Question 29

Enzyme that traps Galactose inside the cell

Answer 29

Galactokinase (counterpart of Glucokinase for Glucose)

Question 30

Diagnosis of lactose intolerance

Answer 30

Positive hydrogen breath test

Question 31

Enzyme that traps Fructose inside the cell

Answer 31

Fructokinase (counterpart of Galactokinase and Glucokinase)

Question 32

Hereditary Fructose Intolerance (lethagry, vomiting, liver damage, hyperbilirubinemia, hypoglycemia, hyperuricemia, renal PCT Fanconi-like defect), an autosomal recessive disease, causes what enzyme deficiency?

Answer 32

Aldolase B/Fruc 1-P aldolase (Fruc-1-P to DHAP and Glyceraldehyde for entry to Glycolysis)

Question 33

Co-factors and co-enzymes required by pyruvate dehydrogenase

Answer 33

Thiamine pyrophosphate (TPP) from Vit. B1, Lipoic acid, CoA from pantothenate, FAD from Vit. B2, NAD from Vit. B3

Question 34

Directly inhibits pyruvate dehydrogenase and activates pyruvate carboxylase

Answer 34

Acetyl CoA (product of PDH)

Question 35

Thiamine deficiency characterized by ataxia, ophthalmoplegia, nystagmus, memory loss and confabulation, cerebral hemorrhage

Answer 35

Wernicke-Korsakoff Syndrome

Question 36

Complication of thiamine deficiency leading to congestive heart failure

Answer 36

Wet beri-beri (high output failure)

Question 37

Aside from Pyruvate DH, what other enzymes require Thiamine

Answer 37

Alpha-ketoglutarate DH, Branched-chain ketoacid DH (The 3 dehydrogenases)

Question 38

Insulin-stimulated glucose transporter

Answer 38

GLUT 4

Question 39

Co-transporter that acts as the “glucose sensor” in beta-islet cells

Answer 39

GLUT 2

Question 40

Direct activators of PFK

Answer 40

AMP, F-2,6-BP

Question 41

Direct inhibitors of PFK

Answer 41

ATP, Citrate

Question 42

Indirect activator of PFK

Answer 42

PFK-2, (in response to) Insulin

Question 43

Recycles back NADH to glycolysis

Answer 43

LDH via malate shuttle

Question 44

Distinguishes Pyruvate Kinase Deficiency from G6PDH Deficiency

Answer 44

Absence of Heinz bodies in PK Deficiency

Question 45

Glycolytic intermediate needed for triglyceride synthesis

Answer 45

DHAP

Question 46

PDH is located in

Answer 46

Mitochondria