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Flashcards in Glycolysis Deck (37):
1

What are the four major fates for glucose in cell:

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

2

What are the products in glycolysis

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

3

Glycolysis is divided into two reactions:

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

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

4

We always have to regenerate ___ for glycolysis to continue

NAD+

5

There is a net gain of how many ATPS

2

6

Production of ATP is:

endergonic

7

Glycolysis is ___under standard conditions

irreversible

8

Glycolysis occurs in the

cytosol

9

Glycolysis is anaerobic.

True

10

Committed steps have a lot of ___modifiers and ___inhibitors

allosteric ; feedback

11

Glycolysis deals with ___reactions divided into ___phases

10; 2 (5+5)

12

What is the first phase of glycolysis

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

13

What is the second phase of glycolysis

Oxidize these two compounds to pyruvate:

14

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

second; first

15

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

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

16

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

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.

17

Make ___ATPS per glucose. But net gain of

4; 2

18

A negative delta G tells you

its not a reversible reaction

19

What are hexokinase isozymes

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.

20

If ADP and AMP levels are high it signals:

an increase in glycolytic pathway

21

Pyruvate is not the endpoint bc

we need to regenerate NAD+

22

What are the fates of pyruvate

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

23

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

take away product

24

What is the Cori cycle

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.

25

When can you get lactic acidosis

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

26

How does lactic acidosis relate to the eyes

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

27

What are some defects in fructose metabolism

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

28

What are the 2 routes fructose can enter glycolysis

1. hexokinase
2. fructokinase

29

What is galactose catalized by

galactokinase; makes galactose 1 phosphate

30

How is galactose metabolism

UDP glucose and galactose intermediate.

31

What is UDP

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.

32

What is GALT deficiency

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

33

Conversion to galactitol by aldose reductase in lens causes

cataracts

34

Oral bacteria are ___anaerobes. An ex is strep mutans

facultative. Can live with or without oxygen

35

Porphyromonas gingivalis is an _____anerobe

obligate; periodontal disease deep in pocket.

36

Strep mutans are

homofermentative or homolactic fermenter (produce > 90% lactate)

37

Sufficient local acid production leads to ion product of ____

calcium