MODULE 2

Question 0

Catalysis occurs at the _________ of the enzyme.

Answer 0

Active site

Question 1

Physically distinct versions of enzymes that catalyze the same reaction.

Answer 1

Isoenzymes

Question 2

With tight and stable attachment to the enzyme.

Answer 2

Prosthetic groups

Question 3

With transient, dissociable attachment to the enzyme.

Answer 3

Cofactors

Question 4

Serves as substrate shuttles.

Answer 4

Coenzymes

Question 5

Is the joining of small biochemical to form larger molecules.

Answer 5

Anabolism

Question 6

Involves both anabolic and catabolic pathways.

Answer 6

Amphibolic pathways

Question 7

Fatty acids are esterified to form __________.

Answer 7

Triacylglycerol

Question 8

Acetyl CoA is oxidized to CO2 and H2O via this cyle.

Answer 8

Citric acid cycle

Question 9

A metabolic pathway by which a 6-carbon glucose molecule is oxidized to two molecules of a 3-carbon sugar called pyruvate in the presence of oxygen.

Answer 9

Glycolysis

Question 10

Glycolysis takes place within the _________ of the cell.

Answer 10

Cytosol

Question 11

It is also referred to as the EmbdenMeyerhof pathway.

Answer 11

Glycolysis

Question 12

Fructose-6-phosphate is converted to Fructose-1,6-biphosphate via which enzyme.

A. Hexokinase
B. Aldolase
C. PFK-1
D. Phosphohexose isomerase

Answer 12

C. PFK-1

Question 13

It is an enzyme that catalyzes the transfer of a phosphoryl group from ATP to a substrate.

Answer 13

Kinase

Question 14

Type IV isoenzyme of hexokinase.

Answer 14

Glucokinase

Question 15

The following are true for the enzyme hexokinase EXCEPT:

A. Found in most tissues
B. Inhibited by glucose 6-P
C. O.1 mM Km for glucose
D. High in liver

Answer 15

D. High in liver

Question 16

After meals, when prostpandial blood glucose are high, liver _________ is significantly active.

Answer 16

Glucokinase

Question 17

Hexokinase requires _______ ion for its activity.

Answer 17

Magnesium

Question 18

After step 2 of glycolysis, which carbon is no longer part of the ring structure?

Answer 18

C1

Question 19

This is considered as the rate limiting enzyme of glycolysis.

Answer 19

Phosphofructokinase

Question 20

Dihydroxyacetone phosphate is converetd to glyceraldehyde-3-phosphate via what enzyme?

Answer 20

Triosephosphate isomerase

Question 21

Enolase is inhibited by __________.

Answer 21

Flouride

Question 22

The enol form of pyruvate undergoes this process to become a more stable pyruvate in keto form.

Answer 22

Tautomerization

Question 23

The branch point molecule of glycolysis.

Answer 23

Pyruvate

Question 24

Pyruvate may also undergo carboxylation to _______ to provide a substrate for gluconeogenesis.

Answer 24

Oxaloacetate

Question 25

The pyruvate dehydrogenase complex consists of 3 enzymes:

Answer 25

``` Pyruvate dehydrogenase (E1) Dihydrolipoyl transacetylase (E2) Dihydrolipoly dehydrogenase (E3) ```

Question 26

The 2-carbon hydroxyethyl group after oxidation of pyruvate binds to..

Answer 26

Thiamine pyrophosphate (TPP)

Question 27

The following inhibits PFK EXCEPT: A. Citrate B. AMP C. ATP D. Glucagon

Answer 27

B. AMP

Question 28

The major energy-producing pathway in the body.

Answer 28

TCA or Kreb's cycle

Question 29

TCA occurs in what part of the cell.

Answer 29

Mitochondrial matrix

Question 30

Acetyl CoA codenses with oxaloacetate to form citrate via which enzyme..

Answer 30

Citrate synthase

Question 31

An enzyme that makes a new covalent bond during a rxn without the involvement of an ATP molecule.

Answer 31

Synthase

Question 32

Two products of the hyrdolysis of the thioester bond in citrate synthase catalysis.

Answer 32

Coenzyme A-SH and citrate

Question 33

Aconitase catalyzes isomerization of citrate to __________.

Answer 33

Isocitrate

Question 34

The first oxidative decarboxylation reaction in the TCA cycle.

Answer 34

Oxidation of Isocitrate to alpha-ketoglutarate.

Question 35

Isocitrate dehydrogenase is allosterically activated by ________ and inhibited by ________.

Answer 35

ADP, NADH

Question 36

The alpha-ketoglutarate is converted to succinyl coenzyme A is considered the ______________ of TCA cycle.

Answer 36

Second oxidative decarboxylation reaction

Question 37

Succinyl CoA is cleaved to succinate via the action of...

Answer 37

Succinyl CoA synthetase

Question 38

Succinate dehydrogenase catalyzes which step in the TCA cycle.

Answer 38

Succinate to fumarate

Question 39

The only enzyme in TCA cycle found in the inner mitochondrial membrane.

Answer 39

Succinate dehydrogenase

Question 40

Water adds across the double bond of fumarate to form _________.

Answer 40

Malate

Question 41

Products of the TCA cycle.

Answer 41

2 CO2, 3 NADH, 1 FADH2, 1 GTP

Question 42

When ATP levels are high, the following occurs EXCEPT: A. NADH allosterically inhibits isocitrate dehydrogenase. B. Citrate inhibits citrate synthase. C. Oxaloacetate is concerted to malate. D. Isocitrate accumulates and favors the accumulation of citrate.

Answer 42

C. Oxaloacetate is concerted to malate.

Question 43

The following enzymes use NAD EXCEPT: A. Succinate dehydrogenase B. Isocitrate dehydrogenase C. Malate dehydrogenase D. Alpha-ketoglutarate dehydrogenase

Answer 43

A. Succinate dehydrogenase

Question 44

TRUE or FALSE: Citric acid cycle is amphibolic.

Answer 44

TRUE

Question 45

This the most important anaplerotic rxn: Pyruvate + ATP + CO2 + H20 ➡️ Oxaloacetate + ADP + Pi This rxn is catalzyed by __________ and its allosteric activator is __________.

Answer 45

Pyruvate carboxylase, Acetyl CoA

Question 46

Primary source of ATP in aerobic organism.

Answer 46

Oxidative phosphorylation

Question 47

ETC located in which specific part of the cell?

Answer 47

Inner mitochondrial membrane

Question 48

Mutations in complex II of the ETC.

Answer 48

Kearns-Sayre Syndrome

Question 49

What are the 3 irreversible and regulated steps in glycolysis?

Answer 49

Step 1: Phosphorylation of glucose Step 3: Phosphorylation of fructose-6-phosphate Step 10: Formation of pyruvate

Question 50

What is the substrate for gluconeogenesis?

Answer 50

Pyruvate

Question 51

90% of gluconeoegenesis occurs in the liver while 10% occurs in the..

Answer 51

Kidney

Question 52

Rate limiting step of gluconeogenesis.

Answer 52

Fructose 1,6 biphosphate ➡️ Fructose 6 phosphate via the enzyme fructose 1,6 biphosphatase

Question 53

Energy expense of the Cori cycle.

Answer 53

4 ATP molecules

Question 54

Glycogenesis occurs int he following EXCEPT: A. Liver B. Muscle C. Cytosol D. Kidneys

Answer 54

D. Kidneys

Question 55

Rate-limiting enzyme of glycogenesis

Answer 55

Glycogen synthase

Question 56

Activated form of glucose.

Answer 56

UDP-glucose

Question 57

Catecholamine that increases glycogenolysis in liver and muscles.

Answer 57

Epinephrine