Session 2 Flashcards
(51 cards)
What is the purpose of the phosphorylation of glucose?
Makes the sugar anionic so prevents it crossing the cell membrane, increases the reactivity of the sugar so it can be metabolised, allows formation of compounds with high phosphoryl-group transfer potential that can transfer phosphate group to ADP.
What is the purpose of the phosphorylation of glucose?
Makes the sugar anionic so prevents it crossing the cell membrane, increases the reactivity of the sugar so it can be metabolised, allows formation of compounds with high phosphoryl-group transfer potential that can transfer phosphate group to ADP.
Which monosaccharide does not contain a chiral centre?
Dihydroxyacetone
Which monosaccharide does not contain a chiral centre?
Dihydroxyacetone
What is the normal concentration of blood glucose?
~5 mmol/L
What level of blood glucose indicates untreated diabetes?
> /= 7.0 mmol/L
What makes a disaccharide non-reducing?
If the aldehyde/ketone groups of both sugars are involved in forming the glycosidic bond.
Where is glycogen synthesised?
The liver and skeletal muscle.
What is produced when starch is hydrolysed?
Glucose and maltose
Why can humans not digest cellulose?
The human GI tract does not produce enzymes that are able to hydrolyse beta-1,4 linkages
What type of reaction is glycolysis?
Catabolic
Where does glycolysis take place?
The cytoplasm
How much glucose does the CNS require?
approx. 140g/24 hours
What type of bond does pancreatic amylase hydrolyse?
a-1,4 bonds
What type of bond does isomaltase hydrolyse?
a1-6 bonds
What is primary lactase deficiency?
A lack of lactase enzyme caused by the absence of lactase persistence allele. Only occurs in adults.
What is secondary lactase deficiency?
A lack of lactase enzymes caused by damage to the epithelial lining of the small intestine. It is generally reversible and can occur in infants and adults.
What is congenital lactase deficiency?
A lack of lactase enzymes caused by an autosomal recessive defect in lactase gene, preventing infants from digesting breast milk. It is extremely rare.
Which two transporters are involved in the absorption of monosaccharides?
Sodium-glucose-transporter-1 (SGLT1)
Glucose transporter-2 (GLUT2)
Which glucose transporter is insulin-regulated?
GLUT4
What is the function of hexokinase?
To phosphorylate glucose
What is the function of hexokinase?
To phosphorylate glucose
What is the function of phosphofructokinase-1?
The phosphorylation of fructose
What is the function of pyruvate kinase?
Converts phosphoenolpyruvate to pyruvate
