3.10 Proteins

Question 1

What are proteins?

Answer 1

proteins are polymers of amino acids (only alpha amino acids)

Question 2

What are amino acids?

Answer 2

Amino acid contain a carboxyl on one end and an amino group on the other.
The can contain many different R groups that control the aminos solubility and function.

Question 3

Why do amino acids self-ionise?

What is the product called?

Answer 3

Amino acids have both acidic and basic properties.
The basic amino group can accept a proton from the acidic carboxyl.
The resulting particle is called a Zwitterion

Question 4

What process forms proteins from amino acids?

Answer 4

Condensation reactions

Question 5

State the names of the groups that connect amino acids within a protein

Answer 5

Can be called an amide group

OR (only for proteins) a peptide link or bond

Question 6

What is the primary structure of a protein?

Answer 6

The primary structure is the order of the amino acids

Question 7

What is the secondary structure of a protein?

Answer 7

The secondary structure is the folding and sheet structures formed due to secondary interactions between the R-groups - it determines the 3D shape

Question 8

What is the tertiary structure of a protein?

Answer 8

The tertiary structure is the over 3D shape of the poly-peptide

Question 9

What is the quaternary structure of a protein?

Answer 9

The quaternary structure is the interactions between 2 or more poly-peptide chains

Question 10

Describe the properties that dictate biological functions of proteins

Answer 10

The 3D shape dictates the biological function of proteins

Question 11

What is an enzyme?

Answer 11

Some proteins are enzymes

They are natural catalysts and thus work to increase the rate of reaction

Question 12

Describe conditions that will change the function of an enzyme and how the function will be changed

Answer 12

If the 3D shape is altered then the biological function is also.
Changes in temperature -
An increase in temperature will increase the vibrations of the protein. This will disrupt the secondary bonding interactions within the protein. As such the 3D structure will change and thus the enzyme is said to e deactivated.

Changes to pH -
A change in pH can protonate or deprotonate parts of the chain thus changing the secondary bonding.
Therefore, the 3D shape would change and deactivate the enzyme.