Glycolysis

Question 1

What is glycolysis

Answer 1

-oxidizing of glucose molecules into pyruvate

Question 2

How is glucose transported into cell and why

Answer 2

• through glut proteins

- water soluble

Question 3

List types of glut proteins and where found

Answer 3

Glut 1 - fetus , blood brain barrier , blood ( RBC )

Glut 2 - kidney , liver , pancreas

Glut 3 - placenta , kidney , neuron

Glut 4 - muscle , fat ( adipose )

Question 4

Diff between glut 1-3 and 4

Answer 4

-glut 4 is insulin dependent and and efficiency proportional to insulin conc

Question 5

Why is glucose anchored with molecule when in cell and what’s the molecule

What enzyme mediates the process

Which c atom is the molecule added to / Now name of glucose

Answer 5

• to prevent it from moving out of cell through bi-directional glut protein
• phosphate
• hexokinase or gkucokinase
• carbon 6 / glucose-6-phosphate

Question 6

Location of hexokinase and glucokinase

Where does the phosphate come from

Answer 6

• mainly in muscle but also in a lot of tissue
• only liver has glucokinase
• ATP is hydrolyzed into ADP

Question 7

What is the next step after glucose phosphorylation, what mediates and is the reacting reversible

Answer 7

• glucose-6-phosphate is isomerized into fructose 6 phosphate ( ketone ) by phosphahextose isomerase
• irreversible

Question 8

What happens to fructose-6-phosphate and what mediates

Answer 8

• converted into fructose 1-6 bisphophatase ( bis due to carbon spaces in between the phosphates )
• phosphafructokinase 1 ( PFK 1 )
• ATP hydrolyzed into ADP

Question 9

What happens to fructose 1,6 BP and what is the enzyme involved

Products formed and differentiate them

Answer 9

• cleaved into 2 three carbon fragments by Aldose
• dihydroxyacetonephosphatase ( DHAP ) has ketone in middle and not used so converted into GA3P
• glyceraldehyde 3 phosphate ( GA3P ) has aldehyde and end and used in further reactions

Question 10

What converts DHAP into GA3P

Answer 10

-triose phosphate isomerase

Question 11

What happens to GA3P ( it’s next 2 steps )

Answer 11

/phosphorylation at carbon 1 by glycealdehyde-3-phosphate dehydrogenase into 1,3 bisphosphate

-NAD+ reacted with 1,3 BP by GA3P DHand is now NADH ( took hydrides ) and GA3P phosphorylated

Question 12

Why are 2 mols of GA3P present

Answer 12

-cause DHAP is convert into GA3P by triose-phosphate-isomerase and there will be 2 mols of GA3P

Question 13

Next step after 1,3 BP formed

Answer 13

-phosphate removed from carbon 1 and now we form 3 phosphoglycerate and enzyme is called phosphoglycerate kinase ( phosphorylation of ADP into ATP )

Question 14

What happens to 3 phosphoglycerate and mediators and product formed

Answer 14

-mutated and phosphate shifter to carbon 2 by phosphoglycerate mutase into 2-phosphoglycerate

Question 15

What occurs to 2-Phosphoglycerate and mediators and product formed

Answer 15

• converted into Enol but with phosphate at alcohol of carbon 2
• now called phosphoenol pyruvate ( has c double bond at carbon 2-3 )

-mediated by enolase

Question 16

Fate of phosphoenol pyruvate and mediators and products formed

Answer 16

• phosphate is removed by pyruvate kinase which phosphorylates ADP
• pyruvate formed

Question 17

2 fates of pyruvate depending on O2 conc

Answer 17

1 anaerobic - hydrides unloaded on pyruvate forming lactic acid

2 aerobic - converted into 2 carbon molecule ( taken to specific molecules for electron transport chain to form ATP )

Question 18

How is lactic acid formed

Effects and fate of glucose

Answer 18

-pyruvate plus NADH into NAD+ and lactic acid by lactate dehydrogenase

• liver covnverted into glucose
• decrease pH ( acidosis , chromatin clumping )

Question 19

Meaning of high LDH levels

Causes

Answer 19

• lot of pyruvate being converted into lactic acid
  /myocardial infarction
  /necrotic bowel

Question 20

Where does glycolysis occur

Answer 20

-cytoplasm