2025 VJC H2 Biology Prelim P2 Answer

1 VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION 2025 HIGHER 2 NAME : ……………………………………………………….………………. CT CLASS: ………………...……… BIOLOGY Paper 2 Structured Questions 9744 / 02 16/09/2025 2 hour Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name and CT class in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. Use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in bracket [ ] at the end of each question or part question. Question Marks 1 2 3 4 5 6 7 8 9 10 11 Total This document consists of 28 printed pages. [Turn over]

2 Answer all questions. 1 In most cell types, ribosomes are the most abundant organelles by number. They are present in both prokaryotic and eukaryotic cells, although their sizes and structures differ. (a) (i) State one structural feature of ribosomes that is common to both prokaryot ic and eukaryotic cells. [1] [Any one] • Composed of ribosomal RNA (rRNA) and proteins; • Consist of a large and a small subunit; (ii) Suggest how the difference in ribosome size between prokaryotic and eukaryotic cells can be exploited in medicine. [2] • Prokaryotic ribosomes are 70S (50S + 30S), eukaryotic ribosomes are 80S (60S + 40S); • Certain antibiotics bind specifically to 70S ribosomes without affecting 80S ribosomes in the cytosol of eukaryotic cells; (b) Unlike prokaryotic and eukaryotic cells, viruses such as SARS -CoV-2 lack ribosomes entirely. Fig. 1.1 shows the structure of the SARS-CoV-2. Fig. 1.1

3 With reference to the information provided, (i) explain how the structural features of SARS-CoV-2 show that it does not fully conform to the cell theory. [2] • Identify at least one missing cellular feature (e.g., no ribosomes, no cytoplasm, no membrane- bound organelles, no plasma membrane enclosing metabolic machinery); • Viruses are more basic than a cell, which contradicts the cell theory that that cells are the smallest unit of life; • Viruses are not made of cells / acellular, which contradicts the cell theory that all living things are made of cells; • Viruses cannot carry out life processes independently as they require a host cell for reproduction, which contradicts the statement that all cells come from pre-existing cells; (ii) compare the genetic material between SARS-CoV-2 and prokaryotic cells. [3] • Both have a single molecule of nucleic acid that carries hereditary information; • For both, genetic material is not enclosed in a membrane-bound nucleus; features SARS-CoV-2 prok