AS Level Biology Paper 2 Midterm examination

Fig. 1.1 shows 2 biological molecules.

a. State the name of the bond in molecule A indicated by the arrow. (1 mark)

b. Molecule B is described as a saturated fatty acid. State why molecule B is described as a saturated fatty acid. (1 mark)

Use this template for your final answer:

a.

b.

Total mark: 2 marks

Molecule A and molecule C dissolve in water.

Molecule B does not dissolve in water.

Explain why molecule A and molecule C dissolve in water, but molecule B does not dissolve in water. (2 marks)

A student was asked to calculate the magnification of the image shown in Fig. 4.1.

The student began by measuring the length of the scale bar in millimetres using a millimetre ruler.

State what the student should do next to obtain the correct answer. (2 marks)

Carbohydrates, proteins and nucleic acids are types of biological molecule.

Within each type, there are examples of molecules that can be described as polymers.

A polymer is a large molecule composed of smaller repeating molecules known as monomers.

Complete Table 4.1 to produce a summary of some named biological polymers.

For your final answers, use this template:

a. amylose -

b. celulose -

c. collagen -

d. DNA -

e. glycogen

Total marks: 4

Explain why an amylose molecule and a cellulose molecule have very different structures, even though they both have glucose as the constituent monomer. (3 marks)

Explain the lock and key theory in enzymes. (3 marks)