releasing energy without oxygen

Question 1

State the NHS guideline daily energy requirement of an adult male and female

Answer 1

MALE - 2500 kcal

FEMALE - 2000 kcal

Question 2

Describe the transport of glucose into the cell using glucose transporters

Answer 2

5 types of glucose transporters

GLUT 1 -
in all tissues - 1 Km - Function : Basal uptake

GLUT 2 - liver and Pancreatic B cells
- 15-20 Km - glucose sensors, high capacity low affinity

GLUT 3 - All tissues - 1 Km - basal uptake

GLUT4 - skeletal/ striated muscle and adipose tissue - 5 Km -
insulin increases Glut 4 to inc glucose uptake

GLUT 5 - small intestines - mainly fructose uptake

Question 3

Describe the inputs and outputs of anaerobic respiration (quantitatively and qualitatively)

Answer 3

glycolysis occurs in the cytosol of the cell.

INPUT
C6H12O6
2 ADP + Pi
2 NAD +2 H+

OUTPUT
2 pyruvate
2 ATP
2NADH

Question 4

Outline glycolysis, including the substrates and products, the phosphorylation of glucose and the production of triose phosphate

Answer 4

• glucose enters the cell via GLUT1 and phosphorylated by ATP to form glucose 6-phosphate. (catalyst = hexokinase)
• glucose 6 phosphate to fructose 6 phosphate - 2 x 3C molecules
• ATP phosphorylates Fructose 6-phosphate to give Fructose 1,6-Bisphosphate = enzyme - phosphofructokinase (rate limiting step)
• Aldolase breaks down Fructose -1,6 biphosphate into Dihydroxyacetone phosphate (DHAP) & Glyceraldehyde-3-phosphate (GAP) *

enzyme useful for glycolysis is GAP, so DHAP is separately converted to GAP as well (Triose phosphate isomerase )

• Redox reaction is occurring
  Oxidising the food and reducing NAD
  First step in glycolysis that gives anything useful out
  GAP converted to 1,3-BPG
  2 NADH obtained as this reaction happens twice

1,3-Biphosphoglycerate is converted to 3-phosphoglyerate

1 phosphate is removed from 1,3-BPG to make 3-PG

2 molecules of ATP produced (

Question 5

Outline the process of lactic acid production

Answer 5

Pyruvate is converted into lactate by lactate dehydrogenase in the muscles
Lactate is moved away from the muscles to the liver.
In the liver, lactate is converted back to pyruvate

Making lactate requires Pyruvate and NADH -> Lactate + NAD+

Question 6

what inhibits hexokinase

Answer 6

competitive inhibition by Glucose 6-phosphate in two ways competitive inhibition and allosteric inhibition (end-product inhibition)

Question 6

what inhibits hexokinase

Answer 6

competitive inhibition by Glucose 6-phosphate in two ways competitive inhibition and allosteric inhibition (end-product inhibition)

Question 7

what are the rate limiting steps in glycolysis

Answer 7

fructose 6 P to Fructose 1,6-Bisphosphaterate controlled by the amount of ATP that is available

• AMP competes w ATP for allosteric site (Upregulates)
• Phosphofructokinase is also down regulated by low pH, so lactic acid lowering the pH would slow down ATP - so less lactic aid produced

Question 8

In low blood glucose

Answer 8

FBPase2 activation in response to glucagon -> breaks down the Fructose 2,6 Bisphosphate to fructose 6 phosphate

upregulates gluconeogenesis