page 02 SECTION 1 — 20 marks Attempt ALL questions 1. The proteome is A all the genes expressed as proteins B the entire set of proteins expressed by the genome C the number of proteins expressed due to alternative RNA splicing D the number of proteins expressed due to alternative RNA splicing and post‑translational modification. 2. Transmembrane proteins carry a signal sequence, which halts translation and directs the ribosome synthesising the protein to dock with the A plasma membrane B endoplasmic reticulum C transport vesicle D golgi apparatus. 3. Cell components can be separated by a technique called differential centrifugation. This technique uses a series of centrifugation steps at specific centrifugation forces (g) for a given time. After each step, the supernatant is removed and the cell components in the pellet identified. The supernatant is re‑centrifuged at a higher centrifugation force for a longer time. The table gives information about a differential centrifugation experiment. Step Centrifuge conditions Cell component(s) in pellet Force (g) Time (minutes) 1 600 10 nucleus, cytoskeleton 2 15 000 15 mitochondria 3 100 000 60 plasma membrane, endoplasmic reticulum fragments Plasma membrane would be present in the supernatant of which centrifugation step(s)? A 1 only B 2 only C 1 and 2 only D 3 only