Test 3 Review

Question 1

Enzymes of irreversible reactions in glycolysis in liver

Answer 1

Glucokinase
Phosphofructokinase
Pyruvate kinase

Question 2

Gluconeogenesis

Answer 2

Synthesis of glucose from noncarbohydrate precursors
Major precursors are lactate, amino acids and glycerol (not fatty acids)
Pathway converts pyruvate into glucose
Pathway is not a reversal of glycolysis

Question 3

3 reactions in glycolysis are irreversible

Answer 3

Hexokinase step
Phosphofructokinase step
Pyruvate kinase step

Question 4

Gluconeogenesis occurs in

Answer 4

Liver

Question 5

Gluconeogenesis

Answer 5

Occurs in liver
Synthesis of glucose from noncarbohydrate precursors
Major precursors are lactate, amino acids and glycerol
Pathway converts pyruvate into glucose
Pathway not a reversal of glycolysis
Bypass the pyruvate - get it from the mitochondria

Question 6

This pathway converts pyruvate into glucose

Answer 6

gluconeogenesis

Question 7

3 irreversible reactions in glycolysis in liver

Answer 7

Glucokinase
Phosphofructokinase
Pyruvate kinase

Question 8

Regulation of Gluconeogenesis

Answer 8

Glycolysis generates ATP, gluconeogenesis consumes ATP
E charge (ATP/ADP ratio) determines which pathway will be most active
Gluconeogenesis and glycolysis are reciprocally regulated

Question 9

Gluconeogenesis _______ ATP

Answer 9

Consumes

Question 10

Glycolysis __________ ATP

Answer 10

Generates

Question 11

Can get glucose from

Answer 11

Glycogen

Question 12

Glucose Storage

Answer 12

Glycogen

Question 13

Enzyme most important in getting glucose from glycogen

Answer 13

Phosphorylase

Question 14

Phosphorylase a

Answer 14

Active form

Question 15

Phosphorylase b

Answer 15

Inactive form

Question 16

Glucose 1-phosphate

Answer 16

Gets trapped in cell

Question 17

Transferase

Answer 17

Debranching enzyme

used to remove long chains

Question 18

alpha-1,6-glucosidase

Answer 18

Glucose is product

Question 19

Glycogen Synthesis

Answer 19

UDP-glucose pyrophosphorylase step

Question 20

Glycogen Synthesis

Answer 20

Branching enzyme step
Branching enzyme breaks alpha (1,4) and forms alpha (1,6) branch points by transferring segments 7 to 8 glucoses in length
Increases solubility
Increases rate at which glycogen can be synthesized and degraded

Question 21

Regulation of Glycogen Metabolism

Answer 21

Regulated by glucagon (from pancreas) and epinephrine (from adrenal medulla)

• can’t get across membrane like steroid hormones
• these two can block pathways when insulin is present

Question 22

Insulin

Answer 22

Can stimulate synthesis

–glucagon and epinephrine can block insulin

Question 23

Citric Acid Cycle

Answer 23

CAC
More ATP generated from glucose than glycolysis
-net 2 ATP - 2 consumed, 4 made
Aerobic conditions
Take place in mitochondria vs cytosol

Question 24

CAC Overview

Answer 24

Oxidation of 2-Carbon units to produce

• 2 CO2 molecules
• 1 GTP
• Electrons in the form of 3NADH and 1FADH2

Question 25

CAC generates

Answer 25

ONE high E containing GTP

Question 26

Cellular Respiration

Answer 26

High E electrons are removed from carbon fuels Electrons reduce O2 - generating a proton gradient Gradient used to synthesize ATP in oxidative phosphorylation

Question 27

Glycolysis and TCA cycle

Answer 27

Carbohydrates - glucose - can be converted to pyruvate in glycolysis Pyruvate from glycolysis can be converted to acetyl CoA --aerobic only Under anaerobic contitions pyruvate is converted to lactate or ethanol Aerobic conditions result in pyruvate entering the mitochondria

Question 28

Pyruvate dehydrogenase

Answer 28

Highly regulated E1-oxidative decarboxylation of pyruvate E2-transfer of acetyl group to CoA E3-Regeneration of the oxidized form of lipoamide

Question 29

High acetyl CoA directly inhibits

Answer 29

E2

Question 30

Isocitrate dehydrogenase

Answer 30

Re-dox reaction Produces NADH -this step is important in determining the rate of the cycle

Question 31

alpha-ketoglutarate dehydrogenase

Answer 31

Complex similar to pyruvate dehydrogenase (PDH)

Question 32

Succinyl CoA synthetase

Answer 32

ONLY step that generates GTP

Question 33

PDH

Answer 33

Turns on and off the citric acid cycle

Question 34

Pentose Phosphate Pathway

Answer 34

This is an anabolic pathway, trying to get 5C sugars (ex ribose and deoxyribose) Produces NADPH needed for reductive biosynthesis Alternate pathway for the oxidation of glucose Initial step is rate limiting -Glucose 6-phosphate dehydrogenate

Question 35

Problem with Pentose Phosphate Pathway

Answer 35

X-linked recessive | Hemolytic anemia because of deficient levels of NADPH in red cells

Question 36

Warberg Effect

Answer 36

In hypoxic conditions we are activating glycolysis (produce energy) followed by lactic acid fermentation in the cytosol, not in the mitochondria

Question 37

SIRT1

Answer 37

Nuclear | When activated will regulate transcription through deacetylation of histones. Genes are wrapped in histones

Question 38

SIRT3

Answer 38

Mitochondrial | Regulate metabolic processes