Pentose phosphate pathway

Question 1

Summarise the pentose phosphate pathway

Answer 1

• Anabolic pathway
• Utilises the 6 carbons of glucose
• Generates 5-carbon sugars

Question 2

Give the primary functions of the pentose phosphate pathway

Answer 2

1. Generate NADPH + H⁺ (Used in reduction)
2. Provide cells with ribose-5-phosphate (Nucleotides + nucleic acids)
3. Rearrange carbon skeletons of dietary carbohydrates

Question 3

Which reactions utilise a large amount of NADPH + H⁺ ?

Answer 3

• Fatty acid biosynthesis
• Steroid biosynthesis

Question 4

The cells of which organs contain a high number of PPP enzymes?

Answer 4

• Liver
• Adipose
• Adrenal cortex
• Testis

Question 5

…% of the oxidation of glucose in the liver occurs via the PPP

Answer 5

30%

Question 6

Give the blood glucose of: Non-ruminant mammals

Answer 6

4-5 mmol/l

Question 7

Give the blood glucose of: Ruminants

Answer 7

2-3 mmol/l

Question 8

Give the blood glucose of: Birds

Answer 8

8-9 mmol/l

Question 9

List the hormones affecting blood glucose conc.

Answer 9

• Adrenaline
• Glucagon
• Glucocorticoids
• ACTH
• STH
• Insulin

Question 10

Adrenalin:

• Effect
• Produced by
• Affected pathways

Answer 10

• Effect: Hyperglycaemia
• Produced by: Adrenal medulla
• Affected pathways:
  
  • Muscle glycogenolysis, glycolysis (+)
  • Muscle glycogenesis (-)

Question 11

Glucagon:

• Effect
• Produced by
• Affected pathways

Answer 11

• Effect: Hyperglycaemia
• Produced by: Pancreas A cells
• Affected pathways:
  
  • Liver glycogenolysis, GNG (+)
  • Liver glycogenesis, glycolysis (-)

Question 12

Glucocorticoids:

• Effect
• Produced by
• Affected pathways

Answer 12

• Effect: Hyperglycaemia
• Produced by: Adrenal cortex
• Affected pathways:
  
  • ​​GNG from amino acids (+)
  • Glycolysis (-)

Question 13

ACTH:

• Effect
• Produced by
• Affected pathways

Answer 13

• Effect: Hyperglycaemia
• Produced by: Adenohypophysis
• Affected pathways: Glucocorticoids (+)

Question 14

STH:

• Effect
• Produced by
• Affected pathways

Answer 14

• Effect: Hyperglycaemia
• Produced by: Adenohypophysis
• Affected pathways:
  
  • ​​Lipolysis (+)
  • GNG from amino acids (-)

Question 15

Insulin:

• Effect
• Produced by
• Affected pathways

Answer 15

• Effect: Hypoglycaemia
• Produced by: Pancreas B cells
• Affected pathways:
  
  • Glucose uptake, glycogenesis, glycolysis (+)
  • Glycogenolysis, GNG, Fat/protein degradation (-)

Question 16

Location of GLUT-1 transporter

Answer 16

• Erythrocytes
• Brain

Question 17

Location of GLUT-2 transporter

Answer 17

• Liver
• Kidney
• Intestine

Question 18

Location of GLUT-3 transporter

Answer 18

Brain

Question 19

Location of GLUT-4 transporter

Answer 19

• Muscle
• Adipose tissue

Insulin sensitive

Question 20

Insulin binding to the receptor results in…

Answer 20

• Induction of signal transduction cascade
• Allows GLUT4 to transport glucose into the cell

Question 21

Symptoms of lactose intolerance

Answer 21

• Cramps
• Bloating
• Diarrhoea

Question 22

Cause of lactose intolerance

Answer 22

Not enough lactase production on the tips of the villus

Question 23

Give the fate of UDP-Glucose after galactolysis

Answer 23

• Lactogenesis
• Chondroitin sulphate
• Glycogenesis via glycogen synthase