Proteins

Page 1

Proteins Questions

1) The table shows some of the organic compounds found in bacterial cell.

Compound percentage of total dry mass Number of different types of molecule

Protien 55 1050

RNA 20.5 463

DNA 3.1 1

Lipid 9.1 4

Glycogen 2.5 1

i) Glycogen and protiens are both polymers. Explain why there can only be one type of glycogen molelcule, but there can be many types of protien ?

ii) Explain why there are many types of RNA found in this cell ?

2) What are protiens ?

3) What is the bond between two amino acids called ?

4)Name the elements that make up amino acids.

5) hydrolysis breaks down bonds between two amino acids. Define hydrolysis.

6) What is the primary structure of a protien ?

7) Explain how a change in the primary structure of a protien changes the shape of the protiens ?

8) Name the bonds used n the tertiary structure of protiens.

9) Describe the food test for protein.

Page 2

Markshceme

1)i) Glycogen contains glucose or one type of monomer. Proteins are made up of many different amino acid.

ii) It includes messenger and transfer RNA. Each genes code for different RNA/Each protiens are derived from dfferent type of RNA.

2) Proteins are polymers made up of monomers called amino acids.

3) Peptide bond.

4) Nitrogen, Carbon, Hydrogen and Oxygen (sulphur)

5) Breaking down a polymer with the use of a water molecule.

6) Number and sequence of amino acids in the polypeptide chain.

7) Change in the primary structure means the amino acids are arranges at different places which leads to change in the bonds in tertiary structure.

8) Ionic Hydrogen and disulphide

9) Add biuret reagent, colour change to purple/violet if protien present.