glycolysis

Question 1

difference between catabolic and anabolic pathways

Answer 1

anabolic- combines small molecules to form complex molecules using energy

catabolic- degrades complex molecules into simple products, captures chemical energy in the form of ATP, allows molecules to be converted to building blocks

Question 2

what is aerobic glycolysis

Answer 2

occurs in cells with mitochondria and oxygen

Question 3

what happens in anaerobic glycolysis

Answer 3

pyruvate reduced to lactate, allows production of ATP in tissues that lack mitochondria

Question 4

what is glycolysis and its purpose

Answer 4

splitting of sugar, provides energy and intermediates for other pathways

Question 5

uses of glucose

Answer 5

storage (glycogen, starch, sucrose), synthesis of structural polymers (extracellular matrix, cell wall polysaccharides), ribose 5-phosphate from oxidation via pentose phosphate path, pyruvate from oxidation via glycolysis (oxidation from energy generation)

Question 6

2 phases of glycolysis

Answer 6

energy investment and energy generation

invests 2 ATP, then 2 NADH and 4 ATP, net gain of 2 ATP

Question 7

name and describe the 10 steps of glycolysis (glucose to pyruvate)

Answer 7

1. hexokinase catalyses transfer of phosphate from ATP to position carbon6 in glucose to make glucose-6-phosphate
2. glucose-6-phosphate converts into fructose-6-phosphate (both are hexose with 6 carbons but furanose replaces pyranose)
3. phosphate transfers from ATP to carbon 1 to make fructose-1,6-bisphosphate
4. splits into 2 molecules with aldolase so now have 2 3-carbon molecules (convertible/reversible)
5. interconverts the 3c substrates, glyceraldehyde-3-phosphate enters second phase (2 molecules so step 6-10 happens twice for 1 glucose)
6. inorganic phosphate (not from ATP) added to reduce NAD to NADH, product formed is 1,3-bisphosphoglycerate
7. 1,3-bisphosphoglycerate donates a phosphate to ADP, catalysed by phosphoglycerate kinase to make 3-phosphoglycerate (substrate level phosphorylation)
8. phosphate moves position, catalysed by phosphoglycerate mutase to make 2-phosphoglycerate
9. water is removed, catalysed by enolase to make phosphoenolpyruvate, shift of phosphate from carbon3 to 2, reversible, redistribution of energy within substrate
10. phosphate group removed and added to ADP, catalysed by pyruvate kinase to make pyruvate

Question 8

what does the phosphorylation of glucose ensure/why is it necessary

Answer 8

ensures the glucose stays inside cell as it is an uncharged molecule and doesnt leave by diffusion, exergonic, release of energy prevents reversal

Question 9

what is a kinase

Answer 9

enzyme which catalyses the transfer of a phosphoryl group from ATP to an acceptor molecule (adds phosphate group from ATP)

Question 10

what kinase is part of the glycolytic pathway

Answer 10

carbohydrate kinase

Question 11

difference between kinase, phosphorylase and phosphatases

Answer 11

kinase- adds phosphate group from ATP

phosphorylases- add inorganic phosphate

phosphatases- removes a phosphate from a phosphorylated substrate

Question 12

is step 1 exergonic or endergonic

Answer 12

exergonic

Question 13

is step 2 exergonic or endergonic

Answer 13

endergonic

Question 14

is step 3 exergonic or endergonic and why

Answer 14

exergonic, energy released to prevent reverse, one direction

Question 15

is step 4 exergonic or endergonic

Answer 15

endergonic

Question 16

is step 5 exergonic or endergonic

Answer 16

endergonic, converts keto group to aldehyde group

Question 17

what is the warburg effect and its diagnostic and therapeutic benefits

Answer 17

normal cells gain energy form oxidative phosphorylation and cancer cells produce energy from glycolysis

diagnostic benefits- radioactive glucose accumulates in malignant cells and can be imaged by PET scans, can selectively enrich/label glucose as cancer cells use more of it for imaging

therapeutic benefits- substances can be tested for cancer treatment, toxic glucose like compounds can target cancer cells

Question 18

what is glycolysis

Answer 18

breaking down glucose to produce energy