Biological Molecules key terms

Question 1

What are monomers

Answer 1

Smaller units from which larger molecules are made.

Question 2

What are polymers

Answer 2

Molecules made from a large number of monomers joined together.

Question 3

What is a condensation reaction

Answer 3

A reaction that joins two molecules together to form a chemical bond whilst eliminating of a molecule of water.

Question 4

What is a hydrolysis reaction?

Answer 4

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

Question 5

What is a monosaccharide?

Answer 5

Monomers from which larger carbohydrates are made

Question 6

How is a glycosidic bond formed?

Answer 6

A condensation reaction between two monosaccharides

Question 7

Name the three main examples of polysaccharides

Answer 7

Glycogen, starch, cellulose

Question 8

Benedict’s test for reducing sugars

Answer 8

Gently heat a solution of a food sample with an equal volume of Benedict’s solution for five minutes. The solution turns orange/ brown if reducing sugar is present.

Question 9

Name the two main groups of lipids

Answer 9

Phospholipids, triglycerides (fats and oils)

Question 10

Give four roles of lipids

Answer 10

Source of energy, waterproofing, insulation, protection

Question 11

What is an ester bond?

Answer 11

A bond formed by a condensation reaction between glycerol and a fatty acid.

Question 12

Describe the emulsion test for lipids

Answer 12

Mix the sample with ethanol in a clean test tube, shake the sample, add water, shake the sample again, a cloudy white colour indicates that lipid is present.

Question 13

What are the monomers that make up proteins?

Answer 13

Amino acids

Question 14

How is a peptide bond formed?

Answer 14

A condensation reaction between two amino acids

Question 15

What is a polypeptide?

Answer 15

Many amino acids joined together

Question 16

Describe the biuret test for proteins

Answer 16

Mix the sample with sodium hydroxide solution at room temperature, add very dilute copper (II) sulphate solution, mix gently, a purple colour indicates that peptide bonds are present.

Question 17

How does an enzyme effect a reaction

Answer 17

It lowers the activation energy

Question 18

Give five factors which can effect enzyme action

Answer 18

Temperature, PH, enzyme concentration, substrate concentration, inhibitor concentration

Question 19

What is a competitive inhibitor?

Answer 19

A molecule with a similar shape to the substrate, allowing it to occupy the active site of the enzyme.

Question 20

What is a non-competitive inhibitor?

Answer 20

A molecule that changes the shape of the enzyme by binding somewhere other than the active site.

Question 21

Hydroxylating

Answer 21

Addition of hydroxyl / OH group.