Proteins, Enzymes And Digestion.

Question 1

What is a micelle?

Answer 1

And emulsified lipid droplet, coated with bile salts to prevent reformation.

Question 2

Proteins are large molecules. True/false?

Answer 2

True

Question 3

How are polypeptides formed?

Answer 3

Joining amino acid monomer units.

Question 4

What 4 groups is the central carbon in an amino acid attached to?

Answer 4

• amino group
• carboxyl group
• hydrogen
• R ( side group, variety of chemical groups )

Question 5

How are dipeptides formed?

Answer 5

In a condensation reaction with amino acid monomers.

Question 6

What happens during a condensation reaction between two monomers in reference to the 4 chemical groups attached to the central carbon?

Answer 6

• OH is removed from the carboxyl group of one amino acid.

- H removed from other amino acid

Question 7

How can polypeptides be broken down?

Answer 7

Hydrolysis reaction

Question 8

What is the primary structure of a protein?

Answer 8

A polypeptide

Question 9

What does the primary structure of a protein do?

Answer 9

Determines the shape of the protein and its function

Question 10

What bond joins monomers?

Answer 10

Peptide bond

Question 11

Why are polypeptides able to form hydrogen bonds in the secondary structure of a protein?

Answer 11

There is an -NH and a -C=O group on either side of the peptide bond, the H is slightly electropositive, the O is slightly electronegative.

Question 12

What shape is caused in the secondary structure of a protein as a result of the hydrogen bonds formed?

Answer 12

It becomes twisted into a 3D shape, e.g. A coil (alpha helix)

Question 13

What re the two variations of proteins?

Answer 13

Fibrous and globular.

Question 14

What is the tertiary structure of a fibrous protein?

Answer 14

Unbranched polypeptide chain that has been tightly wound and packed together closely by glycine, and then twisted into a second helix.

Question 15

Name a fibrous protein.

Answer 15

Collagen

Question 16

What us the quartenary structure of a fibrous protein?

Answer 16

3 polypeptide chains wound together similarly to fibres in a rope.

Question 17

What does collagen do?

Answer 17

Joins muscles and bones.

Question 18

Name examples of globular proteins and what they do.

Answer 18

Enzymes and haemoglobin

Carry out metabolic functions

Question 19

What type of protein are enzymes?

Answer 19

Globular

Question 20

What conditions must be present for a biochemical reaction to occur?

Answer 20

• for substrates to collide in order to react they require sufficient energy
• energy of products must be less than reactants
• activation energy

Question 21

What does the protein biruet test detect?

Answer 21

Polypeptide bonds

Question 22

What are the steps to the protein biruet test?

Answer 22

• place sample in test tube, add equal volume of sodium hydroxide at room temp.
• add a few drops of dilute copper sulphate solution and mix

Question 23

What is the positive and negative result of a protein biuret test?

Answer 23

Positive - purple

Negative - blue

Question 24

Which part of the enzyme is functional?

Answer 24

The active site

Question 25

What is formed when the substate bonds with the enzyme’s active site?

Answer 25

Enzyme-substrate complex

Question 26

How does the induced fit model work?

Answer 26

The enzyme is flexible and changes shape in the presence of the substate.

Question 27

How does the induced fit model suggest the enzyme lowers the activation energy?

Answer 27

When altering in shape, it puts a strain on substate distorting a particular bond in the substrate, changing the activation energy.

Question 28

What is the secondary structure of a protein?

Answer 28

Alpha helix of beta pleated sheets held together by hydrogen bonds.

Question 29

What is the quaternary structure of a protein?

Answer 29

2 or more polypeptides held together.

Question 30

What is an example of a quaternary globular protein?

Answer 30

Haemoglobin, chlorophyll.

Question 31

What is the tertiary structure of a globular protein?

Answer 31

Secondary structure folded and held together by ionic, hydrogen and disulphide bonds?