Carbohydrates

Question 1

How to test for sugars

Answer 1

Benedicts reagent
heat it
colour change(present should be brick red)

if no colour change, add hydrochloric acid and sodium hydrogen carbonate (if colour change occurs then a non reducing sugar is present)

Question 2

using a colorimeter

Answer 2

equibrilate it by adding one of 0 concentration

use known concentrations and compare the colour change

Question 3

test starch

Answer 3

add iodine

if black then present

Question 4

Maltose

Answer 4

2 alpha glucose

Question 5

sucrose

Answer 5

a-glucose and fructose

Question 6

lactose

Answer 6

glucose and galactose

Question 7

starch

Answer 7

amylose and amylopectin

Question 8

amylose (3)

Answer 8

chain of alpha glucose

coiled

compact (good for storage)

Question 9

amylopectin

Answer 9

branched (can be added and taken away when necessary)

alpha glucose

Question 10

glycogen

Answer 10

branched

compact

alpha cells secret this in the pancreas (islets of langerhan)

Question 11

cellulose

Answer 11

long unbranched chains of beta glucose

strong fibres called microfibrils form which help it to provide structural support for plants (cell walls)

Question 12

how to test for non reducing sugars

Answer 12

add dilute hydrochloric acid

heat in water bath

neutralise with sodium hydrogencarbonate

carry out benedicts test

Question 13

glucagon

Answer 13

breaks down glycogen to glucose