page 02 SECTION 1 — 25 marks Attempt ALL questions 1. Primary cell lines have A a limited number of cell divisions and are sourced from tumours B a limited number of cell divisions and are sourced directly from normal animal tissue C an indefinite number of cell divisions and are sourced from tumours D an indefinite number of cell divisions and are sourced directly from normal animal tissue. 2. The proteome is larger than the number of genes in the genome of an organism because A not all genes are expressed as proteins in a particular cell B post translational modifications generate multiple RNAs from a single gene C alternative splicing generates multiple RNAs from a single gene D each mRNA molecule is translated by many ribosomes. 3. A neuron in a squid, running from the brain to the tentacles, is 0·9 m long. A 25 mm length of neuron is depolarised every 0·001 s. The time taken for an impulse to travel the length of this neuron is A 0·000028 s B 0·000036 s C 0·028 s D 0·036 s