1.6 proteins

Question 1

What are proteins

Answer 1

Proteins are biological molecules

Question 2

What are proteins made out of

Answer 2

Amino acids (monomers)

Question 3

What is the general structure of a protein

Answer 3

An amine group (H2N)
R group
H
Carboxyl group (COOH)

All of which are bonded to a carbon

Question 4

What type of reactions forms a dipeptide, and what does it mean

Answer 4

Condensation reaction. Water is a result of this type of reaction

Question 5

What happens in the primary structure of proteins

Answer 5

The sequence of amino acids as determined by genes.
They are joined by peptide bonds

Question 6

What happens in the secondary structure of proteins. State 2 examples of them.

Answer 6

Folding caused by weak hydrogen bonds (between H, O and N)

• Alpha helix
• Beta sheets (mainly structural e.g keratin & collagen)

Question 7

What happens in the tertiary structure of proteins. As a result what does this form?

Answer 7

Further folding caused by interactions between different R groups.
Forming:
- Ionic bonds
- Hydrogen bonds
- Disulfide bridges

Question 8

What is an example of a protein with the tertiary structure

Answer 8

Globular proteins e.g enzymes

Question 9

What can happen to the bonds in the tertiary structure

Answer 9

The bonds can be broken by changes in pH and an increase of temperature

Question 10

What happens in the quaternary structure of proteins

Answer 10

Two or more polypeptide chains bonded together
- Some may contain ‘prosthetic groups’

An example: Haemoglobin and antibodies

Question 11

Where are peptide bonds found (within proteins)

Answer 11

In the primary, secondary and tertiary structure of proteins

Question 12

Where are hydrogen bonds found (within proteins)

Answer 12

The secondary and tertiary stucture

Question 13

Where are disulfide bridges and ionic bonds found (within proteins)

Answer 13

In the tertiary structure ONLY