Pentose phosphate pathway Flashcards
Summarise the pentose phosphate pathway
- Anabolic pathway
- Utilises the 6 carbons of glucose
- Generates 5-carbon sugars
Give the primary functions of the pentose phosphate pathway
- Generate NADPH + H+ (Used in reduction)
- Provide cells with ribose-5-phosphate (Nucleotides + nucleic acids)
- Rearrange carbon skeletons of dietary carbohydrates
Which reactions utilise a large amount of NADPH + H+ ?
- Fatty acid biosynthesis
- Steroid biosynthesis
The cells of which organs contain a high number of PPP enzymes?
- Liver
- Adipose
- Adrenal cortex
- Testis
…% of the oxidation of glucose in the liver occurs via the PPP
30%
Give the blood glucose of: Non-ruminant mammals
4-5 mmol/l
Give the blood glucose of: Ruminants
2-3 mmol/l
Give the blood glucose of: Birds
8-9 mmol/l
List the hormones affecting blood glucose conc.
- Adrenaline
- Glucagon
- Glucocorticoids
- ACTH
- STH
- Insulin
Adrenalin:
- Effect
- Produced by
- Affected pathways
- Effect: Hyperglycaemia
- Produced by: Adrenal medulla
-
Affected pathways:
- Muscle glycogenolysis, glycolysis (+)
- Muscle glycogenesis (-)
Glucagon:
- Effect
- Produced by
- Affected pathways
- Effect: Hyperglycaemia
- Produced by: Pancreas A cells
-
Affected pathways:
- Liver glycogenolysis, GNG (+)
- Liver glycogenesis, glycolysis (-)
Glucocorticoids:
- Effect
- Produced by
- Affected pathways
- Effect: Hyperglycaemia
- Produced by: Adrenal cortex
-
Affected pathways:
- GNG from amino acids (+)
- Glycolysis (-)
ACTH:
- Effect
- Produced by
- Affected pathways
- Effect: Hyperglycaemia
- Produced by: Adenohypophysis
- Affected pathways: Glucocorticoids (+)
STH:
- Effect
- Produced by
- Affected pathways
- Effect: Hyperglycaemia
- Produced by: Adenohypophysis
-
Affected pathways:
- Lipolysis (+)
- GNG from amino acids (-)
Insulin:
- Effect
- Produced by
- Affected pathways
- Effect: Hypoglycaemia
- Produced by: Pancreas B cells
-
Affected pathways:
- Glucose uptake, glycogenesis, glycolysis (+)
- Glycogenolysis, GNG, Fat/protein degradation (-)
Location of GLUT-1 transporter
- Erythrocytes
- Brain
Location of GLUT-2 transporter
- Liver
- Kidney
- Intestine
Location of GLUT-3 transporter
Brain
Location of GLUT-4 transporter
- Muscle
- Adipose tissue
Insulin sensitive
Insulin binding to the receptor results in…
- Induction of signal transduction cascade
- Allows GLUT4 to transport glucose into the cell
Symptoms of lactose intolerance
- Cramps
- Bloating
- Diarrhoea
Cause of lactose intolerance
Not enough lactase production on the tips of the villus
Give the fate of UDP-Glucose after galactolysis
- Lactogenesis
- Chondroitin sulphate
- Glycogenesis via glycogen synthase
