Biological Molecules

Question 1

Starch/glycogen

Answer 1

Storage – α glucose
Helical shape so compact
Insoluble molecule so osmotically inactive
Branched so glucose is easily hydrolysed/added
Large so cannot leave cell

Question 2

Cellulose

Answer 2

Structural molecule - β glucose
Long, unbranched chains of glucose
Joined by glyosidic bonds
Cellulose molecules hydrogen bonded together
To form fibrils
Provides strength

Question 3

Structure of proteins

Answer 3

Polymer of amino acids
Joined by peptide bonds
Formed by condensation reaction
Primary structure is order of amino acids in the chain
Secondary structure is specific folding of polypeptide chain held by hydrogen bonds
Tertiary structure is 3-D folding of polypeptide chain held by hydrogen bonds, ionic and disulfide bonds
Quaternary structure is made of two or more polypeptide chains.

Question 4

ATP

Answer 4

Consists of adenine, ribose and 3 phosphate groups
Releases energy in small manageable amounts
Hydrolysed in a one step
Energy available rapidly
Used to phosphorylates molecules
Used to lower activation energy
Reformed by adding phosphate to ADP