Questions and Answers for the Module BIOL111 Molecules of Life

EXAMPLE BIOL 111 end of module test – for Moodle web page.

1. Define the term ‘isotope’. (1 mark)

The same element but different mass number.

2. What type of covalent bond connects a hydrogen atom to an oxygen atom in a
water molecule? (1 mark)
Polar

3. Define ‘specific heat’ of water. (1 mark)
The amount of heat absorbed or lost in order to alter the temperature of 1g of water by 1 oC.

4. Draw a detailed picture of one molecule of methane. (2 marks)




One central carbon with covalent bonds to four atoms of hydrogen.

5. What is the pH of 0.01M NaOH? Show all working. (5 marks)

0.01M NaOH has an [OH-] = 10 -2. (1 mark)

[H+] x [HO-] = 10-14 (1 mark)

Therefore, H+ = 10 -12. (1 mark)

pH = -log10[H+] (1 mark)

therefore pH of 0.01M NaOH= - (-12) = +12 (1 mark)

6. Write the sequence of the mRNA molecule synthesized from a DNA template
strand with the sequence 5’-ATCGTACCGTTA-3’ (3 marks)


Answer: 5’-UAACGGUACGAU-3’

7. Determine the net charge of the predominant form of Glu at (a) pH 1.0, (b) pH 3.0,
(c) pH 6.0 and (d) pH 11.0. The structure of Glu including pKa values for the
ionisable groups is shown below. (4 marks)