Carbohydrates 2 Flashcards Preview

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Flashcards in Carbohydrates 2 Deck (12)
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1
Q

Name the 6 types of carbs in our diet.

A
Starch
Glycogen
Cellulose/hemicellulose
Oligosaccharides
Lactose, sucrose, maltose
Glucose, fructose
2
Q

What is the process of digestion?

A

Mouth -> Stomach -> Duodenum -> Jejenum

3
Q

Can cellulose/hemicellulose be digested by the gut? What does this answer do?

A

No.

Causes increase faecal bulk and decreased transit time.

4
Q

Lactose intolerance is the most common ______ deficiency.

A

Disaccharide.

5
Q

Lactose is osmotically active. What does this mean for the body?

A

Draws water out from the gut into the lumen causing diarrhoea.

6
Q

What is the process of absorbed glucose?

A

Glucose diffuses through the intestinal epithelium cells into the liver
Phosphorylated into G6P by hepatocytes
G6P cannot diffuse out of the cell

7
Q

What happens to glucose when concentrations are normal or when they are high?

A

Normal - glucose can go around the body to other tissues

High - liver takes all the glucose

8
Q

Glycogen is found __% in the liver and skeletal muscle.

A

90

9
Q

When glycogen concentration falls, what happens in the a. liver and b. skeletal muscle.

A

Glycogen -> G6P -> Glucose in the blood

Glycogen -> G6P -> Lactate

10
Q

What is step 1 in the synthesis of glycogen?

A

Glycogenin covalently binds to glucose forming chains of approx 8 glucose residues
Glycogen synthase extends the glucose chains

11
Q

What is step 2 in the synthesis of glycogen?

A

Chains formed by glycogen synthase are broken down by glycogen branching enzymes and rebonded to form branches.

12
Q

What is the process of the degradation of glycogen?

A

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.