Biochemistry week 9

Question 1

What is the central role of glycolysis

Answer 1

• The primary pathway for glucose metabolism which is utilised by cells including micorbes and RBC

Question 2

What are the end products of glycoysis

Answer 2

• Pyruvate which is a 3 carbon carboxylic acid

Question 3

What happens to pyruvate in cells with mitochondria

Answer 3

• Pyruvate is further metabloized to carbon dioxide and water through aerobic pathways

Question 4

What happens to pyruvate in cells without mitochondria

Answer 4

• Pyruvate is converted into lactic acid, which is released into the blood

Question 5

Explain ATP production in glycolysis

Answer 5

• Anerobic glycolyis produces 2 moles of ATP per mole of gluocse metabloised into lactate
• And RBC use this ATP maintain electrochemical gradient across their membrane

Question 6

Explain the glucose uptake and initiation process

Answer 6

GLUCOSE UPTAKE
-Glucose enters cells, including red blood cells (RBCs), via the GLUT-1 transporter,
INITIATION PROCESS
-The first step of glycolysis is the phosphorylation of glucose to glucose-6-phosphate (Glc-6-P), catalyzed by hexokinase, requiring ATP.

Question 7

Name the three stages of glycolysis

Answer 7

-Investment stage
Splitting stage
Yield stage

Question 8

Explain what happens in the investment stage

Answer 8

1.- 1ATP mol is used to phosphorylate glucose to glucose 6 phosphate catalyzed by the enzyme hexokinase
2.- Glucose 6 phosphate is convert into fructose 6 phosphate by phosphoglucose isomerase

3. Another (2nd) mol of ATP is used to phosphorylate fructose 6 phosphate itno fructose-1,6-bisphosphate. This reaction is catalyzed by phosphofructokinase-1

Question 9

What happens in the splitting stage

Answer 9

• Fructose-1,6 bisphosphate is cleaved(split) into 2 triose phosphates:
• dihydroxyacetone phosphate and
  -glyceraldehyde-3-phosphate
• ONLY glyceraldehyde-3-phosphate continues through to the yield stage

Question 10

What does the yield stage of glycolysis produce

Answer 10

• It produces 4 moles of ATP, yielding a net gain of 2 moles of ATP per mole of glucose converted into lactase

Question 11

What is the commitment stage

Answer 11

This is when phosphofructokinase(enzyme) catalyses the phosphorylation of fructose-6-phosphate into fructose-1,6-bisphosphate in the investment stage in glycolysis

Question 12

What happens after the products from spliting stage are produced

Answer 12

-glyceraldehye 3 phosphate is oxidised and NAD+ is reduced into NADH
to produce 1,3bisphosphoglycerate

Question 13

Explain the formation of the first ATP molecule

Answer 13

• phosphoglycerate kinase transfers
  high energy phosphate from 1,3Bisphosphoglycerate to ADP to form ATP

Question 14

Where does the Tricarboxylic Acid(TCA) cycle occur

Answer 14

• In the mitochondria

Question 15

What is the role of the TCA cycle in Metabolism

Answer 15

• Serves as a shared metabolic pathway for all fuels

Question 16

What is the function of the TCA cycle in Energy production

Answer 16

• Provides majority of the reduced coenzymes required for ATP generation in the ETC

Question 17

What is the 2 major Dual functions of the TCA cycle

Answer 17

• Energy production: Facilitates ATP generation
  Biosynthesis:
  -Provides intermediates for various biosynthesis process

Question 18

Describe 3 major functions of the TCA cycle

Answer 18

• It provides a common ground for interconversion of fuels and metabolites
  -Four oxidative steps produce free energy for ATP synthesis
  -Actely CoA is a common product

Question 19

Where is Acetly CoA located

Answer 19

• In the mitochondrial matrix

Question 20

What are the 2 rolesthat Acetyl coA has

Answer 20

• Mitochondrial Role
• Cytoplasmic Role