Carbohydrates 2 Flashcards
Name the 6 types of carbs in our diet.
Starch Glycogen Cellulose/hemicellulose Oligosaccharides Lactose, sucrose, maltose Glucose, fructose
What is the process of digestion?
Mouth -> Stomach -> Duodenum -> Jejenum
Can cellulose/hemicellulose be digested by the gut? What does this answer do?
No.
Causes increase faecal bulk and decreased transit time.
Lactose intolerance is the most common ______ deficiency.
Disaccharide.
Lactose is osmotically active. What does this mean for the body?
Draws water out from the gut into the lumen causing diarrhoea.
What is the process of absorbed glucose?
Glucose diffuses through the intestinal epithelium cells into the liver
Phosphorylated into G6P by hepatocytes
G6P cannot diffuse out of the cell
What happens to glucose when concentrations are normal or when they are high?
Normal - glucose can go around the body to other tissues
High - liver takes all the glucose
Glycogen is found __% in the liver and skeletal muscle.
90
When glycogen concentration falls, what happens in the a. liver and b. skeletal muscle.
Glycogen -> G6P -> Glucose in the blood
Glycogen -> G6P -> Lactate
What is step 1 in the synthesis of glycogen?
Glycogenin covalently binds to glucose forming chains of approx 8 glucose residues
Glycogen synthase extends the glucose chains
What is step 2 in the synthesis of glycogen?
Chains formed by glycogen synthase are broken down by glycogen branching enzymes and rebonded to form branches.
What is the process of the degradation of glycogen?
Glucose monomers removed one at a time by glycogen phosphorylase
Debranching enzymes remove branches
Enzyme removes 3 glucose residues and rebinds them to the nearest non-reducing end
Glucosidase activity removes final glucose
Leaves an unbranched chain which can be degraded or synthesised.
