1A Biological Molecules

Question 1

Define the term ‘Polymer’

Answer 1

Large, complex molecules composed of long chains of monomers joined together

Question 2

Give an example of a monomer

Answer 2

eg: monosaccharides
amino acids
nucleotides

Question 3

Name the monosaccharides that make up carbohydrates

Answer 3

glucose, fructose, galactose

Question 4

What type of sugar is glucose?

Answer 4

A hexose sugar

Question 5

State the difference in structure between an alpha and a beta glucose

Answer 5

Alpha glucose has the h on top and the oh on the bottom while the beta has them the other way.
alpha beta
h oh
c c
oh h

Question 6

What type of reaction joins monosaccharides together? Describe what happens.

Answer 6

A condensation reaction, a glycosidic bond is formed when a h20 molecule is released

Question 7

What is formed as a product of the condensation of 2 monosaccharides?

Answer 7

A disaccharide

Question 8

What two monosaccharides join together to make these disaccharides?
Maltose
Lactose
Sucrose

Answer 8

Maltose = two a-glucose
Lactose = glucose + galactose
Sucrose = glucose + fructose

Question 9

Describe the structure of starch

Answer 9

Alpha glucose
Amylose - unbranched 1,4 glycosidic bonds, coiled and compact
Amylopectin - branched 1,4 1,6 bonds
Insoluble
Compact

Question 10

Describe cellulose structure

Answer 10

Long straight chains
Beta glucose
Microfibrils are made of cellulose chains joined by cross linkages of hydrogen bonds

Question 11

Describe glycogen structure

Answer 11

Alpha glucose
1,4 and 1,6 glycosidic bonds
Highly branched
Large but compact
Insoluble

Question 12

Describe the test for reducing sugars

Answer 12

Add food sample to Benedict’s reagent
Heat gently
Turns blue -> brick red

Question 13

Describe the test for nonreducing sugars

Answer 13

Add HCl acid and heat gently
Add neutraliser
Add Benedict’s reagent and heat gently
Brick red