Glycolysis

Question 1

Glucose Store

Answer 1

Glycogen

Question 2

Why glucose levels are kept consistent in blood

Answer 2

Some tissues can only use glucose in metabolism (eg brain and RBCs), hypoglycemia =confusion, coma and death, hyperglycemia = confusion , cornea damage and death and ATP

Question 3

GLUT1 Transformer

Answer 3

Facilitated diffusion of glucose into brain and erythrocytes

Question 4

GLUT 2 Transformer

Answer 4

Facilitated diffusion of glucose into hepatocytes

Question 5

GLUT 3 Transformer

Answer 5

Facilitated diffusion of glucose into neurons

Question 6

GLUT 4 Transformer

Answer 6

Facilitated diffusion of glucose into adipose tissue and skeletal muscles

Question 7

SGLT Transformers

Answer 7

Glucose secondary active transport

Question 8

How is glucose trapped in cells

Answer 8

Phosphorylated by hexokinase (most cells)/glucokinase (parenchynl cells and pancreatic islet cells) transforming into glucose-6-phosphate. Phosphate can’t move through pumps or across membrane

Question 9

Hexokinase Outline

Answer 9

Low Km (high glucose affinity) and low Vmax (enzyme works slowly). Allows for glucose to enter essential tissue eg brain under fasting conditions. Low enzyme capacity. Regulated astosterically by glucose-6-phosphate

Question 10

Glucokinase Outline

Answer 10

High Km (low glucose affinity). Only takes up glucose while it’s high, minimises uptake by liver. Low Vmax = high capacity. Helps monitor blood glucose, motivates liver to absorb glucose. Regulated by glucose conc

Question 11

Glycolysis End Product

Answer 11

2 x Pyruvate (2 x 3 C chains)

Question 12

What conditions are necessary for pyruvate to move into TCA cycle

Answer 12

Oxygen. Aerobic conditions

Question 13

What does Glucose-6-phosphate convert to

Answer 13

Fructose 6 phosphate (still 6 C chain)

Question 14

Fructose-6-kinase conversion

Answer 14

enzyme phosphofructokinase adds phosphate and converts to fructose-1,6-bis-phosphate. Energy from ATP

Question 15

Fructose-1,6-bis-phosphate conversion

Answer 15

dihydroxy-acetone-P splits molecule into 2 smaller glyceraldehyde-3P (3 C chain). Means 2 cycles of glycolysis per 1 glucose molecule

Question 16

Cell energy regulation in glycolysis

Answer 16

Invest 2 ATP at beginning. Obtain 4 ATP and 2 NADH later in glycolysis

Question 17

Phosphofructokinase 1

Answer 17

Glycolysis, limiting enzyme (activity is tightly regulated). Inhibited by ATP (when cell has enough energy) and activated by fructose-1,6-bisphosphate (high substrate conc, created by high insulin and low glucagon).

Question 18

Effects of fructose-1,6-biphosphate

Answer 18

inhibits phosphofructosekinase 1 and inhibits glucogenesis. Controls blood glucose cons

Question 19

Effect of lactic acid accumulation

Answer 19

circulatory collapse or hemorrhage

Question 20

Lactate to pyruvate conversion

Answer 20

reversible

Question 21

Direct ATP Production

Answer 21

Substrate phosphorylation by kinase enzymes

Question 22

Indirect ATP Production

Answer 22

Oxidative phosphorylation. Redox reactions of electron carriers

Question 23

Pyruvate fates

Answer 23

dehydrogenase complex (Acetyl Co A in TCA cycle and precursor fatty acid synthesis), Carboxylase (oxoacetate in TCA or glucogenesis) and Decarboxylase (ethanol)

Question 24

Fate of oxalates

Answer 24

Fat synthesis

Question 25

Pyurvate Dehydrogenase enzymes

Answer 25

pyruvate decarboxylase, dehydrolipoyl transacetylase and dihydrolipoyl dehydrogenase. All irreversible reactions. high ATP inhibits

Question 26

Pyruvate Dehydrogenase Co enzymes

Answer 26

NAD+, Co A, FAD, TPP, Lipoic acid

Question 27

Pyruvate Dehydrogenase Deficiency

Answer 27

Mitochondrial disorder (maternal line). Congetial lactic acidosis. developmental defects, muscular spasming, early death. No effective treatment

Question 28

Arsenic poisoning

Answer 28

Inhibits liopoic acid cofactor. Inhibit pyruvate dehydrogenase. Symptomas neurological disturbances and death