Biological Molecules

Question 1

Name:

The groups of an amino acid

Answer 1

• Amine group - NH₂
• Carboxyl group - COOH
• R group

Question 2

Describe:

The biuret test

Answer 2

• Add biurets solution
• Positive - colour change blue to purple
• Negative - no colour change
• Test for proteins

Question 3

How are polypeptides formed?

Answer 3

Condensation reaction

Question 4

Define:

Primary structure

Answer 4

The sequence of amino acids in a protein

Question 5

Define:

Secondary structure

Answer 5

• Hydrogen bonds forming between amine and carboxyl groups
• alpha helix
• beta pleated sheet

Question 6

Define:

Tertiary structure

Answer 6

• 3d structure formed by the folding of a polypeptide
• Disulfide bridges
• Ionic bonds
• H bonds

Question 7

Describe:

Disulfide bridges

Answer 7

Strong covalent Sulphur-Sulphur bonds

Question 9

Define:

Quaternary Structure

Answer 9

• 3D structure of a protein
• can contain multiple polypeptides

Question 10

Why are globular proteins soluble in water?

Answer 10

• Hydrophobic R groups face inwards
• Hydrophilic R groups face outwards

Question 11

Describe:

The structure + function of globular proteins

Answer 11

• Spherical and compact
• Metabolic processes
• E.G. haemoglobin

Question 12

Describe:

The structure of fibrous proteins

Answer 12

Form long chains/fibres

Question 13

Describe:

The functions of fibrous proteins

Answer 13

• Structure and support
• E.G. collagen

Question 14

Define:

Enzyme

Answer 14

Biological catalyst

Question 15

How do enzymes catalyse reactions?

Answer 15

• Form enzyme-substrate complexes
• Lower activation energy by providing an alternative pathway

Question 16

Describe:

Lock and key model

Answer 16

• Active site has a fixed shape
• Substrate fit into active site exactly

Question 17

Describe:

Induced fit model

Answer 17

• Active site is not directly complementary to substrate
• Changes shape to fit substrate and form ES complex

Question 18

Name:

The two types of enzyme inhibition

Answer 18

• Competitive
• Non competitive

Question 19

Describe:

Competitive inhibition

Answer 19

• The inhibitors bind to the active site to prevent substrate bonding
• Increasing substrate concentration decreased efficiency

Question 20

Describe:

Non-competitive inhibition

Answer 20

• The inhibitor binds to the allosteric binding site
• changes shape of active site to prevent substrate bonding
• Increasing substrate concentration has no impact

Question 21

Name:

Elements found in a protein

Answer 21

C,H,O,N

Question 22

Name:

Bonds created in the formation of quaternary structure?

Answer 22

• Disulphide
• Hydrogen
• Ionic

Question 23

Name:

Elements found in sucrose

Answer 23

C,H,O

Question 24

Name:

Elements found in cholesterol

Answer 24

C,H,O

Question 25

Name:

Elements found in insulin

Answer 25

C,H,O,N,S

Question 26

Name:

Elements found in ATP

Answer 26

C,H,O,N,P

Question 27

What type of biological molecule contains sulphur?

Answer 27

Proteins

Question 28

Name:

The bond in polypeptides

Answer 28

Peptide

Question 29

Define:

Conjugated Protein

Answer 29

Contains a non protein prosthetic group

Question 30

How do fibrous proteins differ from globular proteins?

Answer 30

• Insoluble
• Strong
• Unreactive

Question 31

Calculate the number of amino acids required to code for a protein

Answer 31

Number of amino acids x 3

????

Question 32

What makes proteins strong?

Answer 32

Having many bonds