Chapter 1 - Biological molecules

Question 1

What is a monomer

Answer 1

smaller units from which larger molecules are made

e.g. monosaccharides, amino acids and nucleotides

Question 2

What is a polymer

Answer 2

molecules made of a large number of molecules joined together

Question 3

What is a condensation reaction

Answer 3

reaction that joins two molecules together with the formation of a chemical bond, and involves the elimination of a molecule of water

Question 4

What is hydrolysis

Answer 4

Hydrolysis – reaction that breaks a chemical bond between two molecules and involves the use of a water molecule

Question 5

what is the bond called when two monosaccharides are joined by a condensation reaction (with diagram)

Answer 5

glycosidic

Question 6

what is a monosaccharide and its features

Answer 6

a single sugar unit
mono - one saccharide - sugar
sweet tasting
soluble
reducing sugars
(CH2O)n from 3-6
suffix ose
examples: glucose, galactose and fructose

Question 7

structure of alpha glucose

Answer 7

Question 8

structure of beta glucose

Answer 8

Question 9

carbon positions labelled on an alpha glucose

Answer 9

Question 10

what is the difference between alpha glucose and beta glucose

Answer 10

a– glucose carbon 1 – the hydroxyl (OH) group is below the hydrogen, whereas on
b – glucose carbon 1 – the hydroxyl (OH) group is above the hydrogen

Question 11

what is the test for reducing sugars

Answer 11

a reducing sugar will act as a reducing agent

Question 12

what is a disaccharide and its properties

Answer 12

*Two monosaccharides joined together
*Soluble
*Some are reducing sugars. Some are non-reducing sugars
*Disaccharides are formed by a condensation reaction between two monosaccharides, forming a glycosidic bond.

Question 13

table showing disaccharides

Answer 13

Question 14

What is a non-reducing sugar

Answer 14

a sugar that does not donate electrons, or change colour with benedict’s reagent

Question 15

what is the method of testing for a non-reducing sugar

Answer 15

Question 16

what is a polysaccharide and its features

Answer 16

*Many monosaccharides joined together
*Formed by condensation reactions
*Joined by glycosidic bonds
*Insoluble
*Storage/structural molecules
*Examples: starch, cellulose, glycogen

Question 17

what is the test for starch

Answer 17

*Add two drops of sample to a spotting tile
*Add two drops of iodine solution
*If starch is present, the sample will turn blue-black

Question 18

what are the three main polysaccharides and what monosaccharides are they made out of

Answer 18

Question 19

What are the features of starch

Answer 19

Energy storage in plants
Polymer of a – glucose
1- 4 glycosidic bonds linking glucose molecules in chains
1- 6 glycosidic bonds linking branches to chains

Question 20

What are the features of Glycogen and how is it different from starch

Answer 20

Energy storage in animals
Polymer of a – glucose
1-4 and 1-6 glycosidic bonds so coiled and branched
More 1-6 glycosidic bonds than starch so more glucose available for energy as animals have higher metabolic rates than plants

Question 21

What is the function of starch and glycogen related to their function

Answer 21

Question 22

What is the function of cellulose

Answer 22

Function = Provide strength for plant cell walls

Question 23

What is the structure of cellulose

Answer 23

Polymer of b – glucose molecules linked by 1 – 4 glycosidic bonds
To form bonds, alternate b – glucose molecules invert
Cellulose is therefore long, straight chained and unbranched
Straight cellulose chains run parallel
Parallel cellulose chains linked by hydrogen bonds between adjacent H and OH groups
Cellulose chains make up microfibrils

Question 24

How is cellulose used in the structure of the cell wall

Answer 24

Hydrogen bonds link parallel cellulose chains
These form a cellulose microfibril
Microfibrils form cellulose fibres
Fibres are laid down, anti – parallel and are embedded in a matrix

Question 25

Compare the structures of starch glycogen and cellulose

Answer 25