Carbohydrate Flashcards Preview

Jonathan's Metabolism > Carbohydrate > Flashcards

Flashcards in Carbohydrate Deck (17):
1

How much glycogen can be stored in the body?

Enough for us to last the night. Depletion of glycogen usually occurs just as we wake up

2

When there is excess glucose, which pathway will be dominant?

pentose phosphate pathway for fat and cholesterol synthesis

3

How is glucose cyclised?

the reactive aldehyde attacks the OH on the 5th carbon

4

T/F most human glucose is in the alpha form

True, beta form is more found in cellulose

5

Which molecule triggers insulin release

glucose 6-P

6

How is glucagon release triggered?

by low circulating blood glucose

7

Which enzyme makes glycogen? Which enzyme breaks it down?

glycogen synthase to make
glycogen phosphorylase to break

8

Why is glycogen an ideal glucose store?

it is inert, can be rapidly converted to glucose, same osmotic effect as a molecule of glucose (so liver doesn't swell)

9

What is in the centre of glycogen

glycogenin

10

How does Pompes disease occur?

lack of alpha 1,4-glucosidase, so there is a build up of glycogen

11

T/F Glucagon and stress signal have a common pathway

True, they both use cAMP pathway to turn off storage and turn on usage of glycogen

12

What makes cellulose so tough

hydrogen bonds

13

What features show that humans are true omnivores

teeth - incisors designed to cut, molars designed to crush and grind

Gut - intermediate length

14

How is white rice different from brown rice?

white rice is the isolated endosperm of grain, whereas brown rice still contains bran and germ, making it harder to digest (low GI)

15

T/F Thiamin and fiber are low in whole grain bread

False, they are low in white bread

16

What is the advantage in having fibres when digesting?

Slows down digestion in stomach (so protein digestion can catch up)

Passes through intestine very quickly

17

Why does sucrose have a glycaemic index of 50?

It is half fructose, so only 50% efficient