proteins and amino acids

Question 1

what elements do proteins contain?

Answer 1

carbon, hydrogen, oxygen, nitrogen and sometimes sulphur

Question 2

what are the monomers of proteins?

Answer 2

amino acids are the monomers from which proteins (polymers) are formed

Question 3

how many different types of amino acids are there?

Answer 3

there are 20 different commonly occurring amino acids in living organisms

Question 4

what is the structure of amino acids?

Answer 4

all amino acids have an amino group (NH2) and a carboxylic acid group (COOH) but differ in the atomic group R

Question 5

in basic terms, how do amino acids form proteins?

Answer 5

• amino acids are joined together by peptide bonds (-CONH-) formed by condensation reactions
• two amino acids joined together to form a dipeptide
• many amino acids joined together in a chain form a polypeptide
• a protein may consist of one or more polypeptides

Question 6

are amino acids proteins?

Answer 6

no - a peptide bond must be present for it to be a protein

Question 7

draw the general structure of an amino acid

Answer 7

see notes

Question 8

how is a dipeptide formed?

Answer 8

amino acids are joined together by peptide bonds (-CONH-) formed by condensation reactions

Question 9

how are proteins hydrolysed?

Answer 9

proteins can be hydrolysed by heating with acid or by using enzymes (proteases) at their optimum temperature