Carbohydrates AS

Question 1

define monomers

Answer 1

individual molecule from which polymers are made

Question 2

define polymer

Answer 2

chains of repeating monomer units

Question 3

name a monosaccharide

Answer 3

glucose, galactose, fructose

Question 4

what does glucose and glucose make?

Answer 4

maltose

Question 5

what does glucose and fructose make?

Answer 5

sucrose

Question 6

what does glucose and galactose make?

Answer 6

lactose

Question 7

define disaccharide

Answer 7

2 monosaccharides joined

Question 8

define polysaccharide

Answer 8

many monosaccharides joined in condensation reactions

Question 9

define and name reducing sugars

Answer 9

can donate electrons. all monosaccharides and maltose

Question 10

which sugars are non-reducing

Answer 10

sucrose, lactose and polysaccharides e.g. starch

Question 11

how are monosaccharides joined together

Answer 11

with a condensation reaction to form a glycosidic bond

Question 12

how do you break down disaccharides

Answer 12

add water on a hydrolysis reaction, breaking glycosidic bonds

Question 13

test for a reducing sugar

Answer 13

add benedicts reagent and heat. turns red/yellow/green

Question 14

test for a non-reducing sugar

Answer 14

add benedicts and heat. stays blue. then add hydrochloric acid to hydrolyse add sodium hydrogen carbonate solution to neutralise then add benedicts solution and heat turns red/yellow/green

Question 15

test for starch

Answer 15

add iodine solution. Turns blue/black

Question 16

adaptations of starch

Answer 16

coiled to make it compact. insoluble doesn’t affect water potential. long chain cant cross cell membrane. polymer of alpha glucose so provides glucose for respiration. branched so glucose is easily ready.

Question 17

how does cellulose give cells strength

Answer 17

long unbranched beta glucose. several chains lie side by side and form microfibrils. H bonds hold chains together. strong in large numbers. only 1,4 glycosidic bonds.

Question 18

adaptations of glycogen

Answer 18

shorter, more branched than starch can be hydrolysed easier. spiral shape compact. 1,4 and 1,6 glycosidic bonds.

Question 19

how to find quantity of reducing sugar using only benedicts test

Answer 19

filter and dry, find mass/weight

Question 20

method for using a calibration curve to find sugar concentration

Answer 20

make known sugar concentration. use colorimeter to measure absorbance of each and plot curve on graph. find conc. of sample from calibration curve.