4.7 amino acids, peptides and proteins

Question 1

What’s the structural formula of alpha amino acids

Answer 1

α-amino acids consist of a central α-carbon with an NH2 (amino group) and a COOH group bonded to it.

Question 2

Why do amino acids have high melting points?

Answer 2

There are strong ionic bonds between the negative COO- group and positive NH3+ group
Require high amount of energy to break.

Question 3

What is the amphoteric nature of amino acids

Answer 3

When α-amino acids are dissolved in an acidic solution, they gain a proton, and if dissolved in a basic solution, they lose a proton.

Question 4

How to form a dipeptide

Answer 4

Dipeptides can be formed from two molecules of the same amino acids as well as one molecule from two different amino acids through a condensation reaction where a small molecule eg water is lost.

Question 5

How to form a protein

Answer 5

2 or more peptides join they form a polypeptide which form proteins

Question 6

What is a primary amino acid

Answer 6

Sequence of amino acids making up protein chain

Question 7

What is a secondary amino acid

Answer 7

How parts of the protein can fold up to form an α-helix that is held in place by hydrogen bonds or a β-pleated sheet. In the β-pleated sheets, amino acids form a shape like a piece of paper stabilized by hydrogen bonds between amino acids in different polypeptide chains.

Question 8

What is a tertiary protein

Answer 8

This refers to the protein as a whole and the way the α-helices or β-pleated sheets of the protein fold with respect to each other.

Question 9

What are the essential roles of proteins in living systems

Answer 9

Proteins are an essential component of a healthy diet. In the body they are used for growth and repair.
They also serve many structural functions, e.g. in nails, feathers, skin and the collagen of cartilage.
Some proteins are enzymes which function as biological catalysts.
Others act as hormones; an example is insulin which helps to regulate glucose levels.