Glycolysis

Question 1

What are the four major fates for glucose in cell:

Answer 1

1. Synthesis of structural polymers: ECM and cell wall polysaccharides
2. Oxidation via pentose phosphate pathway: ribose 5-phosphate
3. Storage: Glycogen, starch, sucrose
4. Oxidation via glycolysis: Pyruvate

Question 2

What are the products in glycolysis

Answer 2

1. 2 pyruvate
2. 2 NADH
3. 2 H+
4. 2 ATP
5. 2 H2O

Question 3

Glycolysis is divided into two reactions:

Answer 3

1. Glucose + 2 NAD+ = 2 pyruvate + NADH + 2H+

2. 2 ADP + 2Pi = 2 ATP + 2 H2O

Question 4

We always have to regenerate ___ for glycolysis to continue

Answer 4

NAD+

Question 5

There is a net gain of how many ATPS

Answer 5

2

Question 6

Production of ATP is:

Answer 6

endergonic

Question 7

Glycolysis is ___under standard conditions

Answer 7

irreversible

Question 8

Glycolysis occurs in the

Answer 8

cytosol

Question 9

Glycolysis is anaerobic.

Answer 9

True

Question 10

Committed steps have a lot of ___modifiers and ___inhibitors

Answer 10

allosteric ; feedback

Question 11

Glycolysis deals with ___reactions divided into ___phases

Answer 11

10; 2 (5+5)

Question 12

What is the first phase of glycolysis

Answer 12

Invest energy (from ATP) to break bonds and create two “high energy” 3 carbon compounds

Question 13

What is the second phase of glycolysis

Answer 13

Oxidize these two compounds to pyruvate:

Question 14

More energy is released in the ___phase than used in the ___first phase

Answer 14

second; first

Question 15

What are the steps of the first (investment) phase of glycolysis

Answer 15

1. Phosphoralate glucose via hexokinase
2. Rerrangement of enzymes –>phosphohexose isomerase
3. Phosphorlate again: Fructose 6 -phosphate into fructose 1,6 biphosphate via phosphofructokinsae 1. This is the committed step!
4. Aldolase Cleaves fructose 1.6 bisphosphate into 2 -3 carbon phosphoralated compounds: Glyceraldehyde 3-phosphate and Dihydroxyacetone phosphate which gets rerragnged back to glyceraldehyde 3 phosphate which is the only one that continues in the cycle

Question 16

What are the steps of the second (payoff) phase of glycolysis

Answer 16

1. Glyceraldeyhe 3 phosphate gets phosphoralated via G3P dehydrogenase with inorganic phosphate to 1, 3 bisphosphate. This is the step that converts NAD+ to NADH. The enzyme that does this is a dehydrogenase!
2. Taking off phosphate group via phosphoglycerate kinase (execption!) 1-3 Bisphosphoglycerate; dephosphoralate and make 1 ATP for each G3P.
3. Arrange 3 phosphoglycerate to 2 phosphoglycerate via phosphoglucomutase.
4. Enolase dehydrates 2 phosphoglycerate to form phosphoenolpyruvate (PEP). 5. Pyruvate kinase converts PEP to Pyruvate which generates ATP.

Question 17

Make ___ATPS per glucose. But net gain of

Answer 17

4; 2

Question 18

A negative delta G tells you

Answer 18

its not a reversible reaction

Question 19

What are hexokinase isozymes

Answer 19

Hexokinase 1: main enzyme in brain and RBC; have highest affinity for glucose
Hexokinase II: Main enzyme in muscle
Hexokinase IV (Glucokinase): found in liver. Cooperatively reg. by glucose. Reaction rate is glucose limited so acts as a glucose sensor. Much higher Km.

Question 20

If ADP and AMP levels are high it signals:

Answer 20

an increase in glycolytic pathway

Question 21

Pyruvate is not the endpoint bc

Answer 21

we need to regenerate NAD+

Question 22

What are the fates of pyruvate

Answer 22

1. Lactate
2. Acetyl CoA –>citric acid cycle
3. Anabolism; oxaloacetate; alanine
4. Fermentation to ethanol in yeast

Question 23

Conversion to lactate is irreversible, but it can be reversible if you

Answer 23

take away product

Question 24

What is the Cori cycle

Answer 24

Under anaerobic conditions we convert glucose into lactate which diffuses into bloodstream taken up by liver and used as a starting point for gluconeogenesis using lactate as its starting point during recovery send glucose back into bloodstream where it gets taken up by skeletal muscle and reconverted into glycogen.

Question 25

When can you get lactic acidosis

Answer 25

1. strenous exercise
2. hypoxia
3. CN poisoning
4. alcohol intoxication
5. Mitochondrial disorders
6. leukemia

Question 26

How does lactic acidosis relate to the eyes

Answer 26

in CL wearers; you get hypoxic conditions. Hypoxia creates lactic acid buildup in cornea which starts impairing function of endothelial cells. You get corneal swelling and clouding

Question 27

What are some defects in fructose metabolism

Answer 27

Deficiences in frutokinase are benign and deal with elevated urine frcutose. Deficiencies in Fructose 1 phosphate aldolase deals with hepatomegaly.

Question 28

What are the 2 routes fructose can enter glycolysis

Answer 28

1. hexokinase

2. fructokinase

Question 29

What is galactose catalized by

Answer 29

galactokinase; makes galactose 1 phosphate

Question 30

How is galactose metabolism

Answer 30

UDP glucose and galactose intermediate.

Question 31

What is UDP

Answer 31

Uridine diphosphate. Found in RNA. Helps with extra binding interactions that help with binding energy that decreases catalytic delta G and brings down activation energy.

Question 32

What is GALT deficiency

Answer 32

Classical galactosemia; Buildup of Gal 1-P which damages liver and brain.

Question 33

Conversion to galactitol by aldose reductase in lens causes

Answer 33

cataracts

Question 34

Oral bacteria are ___anaerobes. An ex is strep mutans

Answer 34

facultative. Can live with or without oxygen

Question 35

Porphyromonas gingivalis is an _____anerobe

Answer 35

obligate; periodontal disease deep in pocket.

Question 36

Strep mutans are

Answer 36

homofermentative or homolactic fermenter (produce > 90% lactate)

Question 37

Sufficient local acid production leads to ion product of ____

Answer 37

calcium