B1.2 Proteins

What is the general structure of amino acids?

Amine group, hydrogen attached to central alpha carbon, carboxyl group, side chain (R group)

Which structure is the only difference between amino acids?

R group - determines chemical properties and behaviour of amino acid

How many amino acids are there?

20

How do amino acids form dipeptides?

Condensation reactions: Amino Acid + Amino Acid → Dipeptide + Water

Where are peptide bonds formed?

Between carboxyl of one and amine of another

What is a polypeptide?

Long chain of amino acids

How are polypeptides formed?

Many condensation reactions at a ribosome during the process of translation

What is the role of proteins in human diet?

Broken down to amino acids by digestive system which are used to synthesise proteins for the body

What are essential amino acids?

9 amino acids that humans require, cannot be synthesised by an animal so must be consumed in the diet

What are non-essential amino acids?

11 amino acids that animals can synthesise using metabolic pathways that transform one amino acid into another

What are considered complete proteins?

Meat and animal products - contain all 9 essential amino acids

What is denaturation?

A change in the shape of a protein, resulting in the loss of function

What is the number of possible combinations of a protein?

Infinite

How does extreme heat cause denaturing of proteins?

Heat disrupts weak bonds → loss of 3D conformation → function lost

How do extreme pH changes cause denaturing of proteins?

Changes R-group charges → disrupts ionic bonds

What happens to enzymes when they denature?

Lose active site shape and stop functioning

What is the covalent bond between monosaccharides called?

Glycosidic bond

What is the covalent bond between glycerol and fatty acids called?

Ester bond

What is the covalent bond between amino acids called?

Peptide bond

What is the role of structural proteins?

Proteins that create a framework for the body's structure and function - membrane, collagen fibres

What are functional proteins?

Biologically active proteins that help to maintain and support normal immune function - enzymes, some hormones

Why are there thousands of protein molecules?

1. Types of amino acids

2. Sequence of amino acids

3. Number of amino acids

How is a polymer formed?

Condensation of monomers

How is a polymer broken down?

Hydrolysis into monomers