2018 J2 HCI H2 Biology Prelims (w/ans)

2 © Hwa Chong Institution 2018 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 1 The electron micrographs 1, 2 and 3 show three different types of cells. Which row is correct? electron micrograph of cell type organelle found in cell type description of organelle A 1, 2 and 3 ribosomes embedded on the smooth endoplasmic reticulum for synthesis of polypeptides B 1 and 2 only vacuoles membrane-bound fluid-filled sacs C 3 only nucleoli dense masses within the nuclei D 2 only centrioles found in animal cells but absent in plant cells 1 2 3

3 © Hwa Chong Institution 2018 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 2 An investigation into the properties of an agent that causes a plant disease was carried out. The process was repeated several times and each successive group of plants developed the disease to the same extent as earlier groups. Which statements, supporting the idea that the infectious agent is a virus, can be concluded from the experiment? 1 Viruses cannot replicate outside of a host cell. 2 Viruses are smaller than bacterial cells and can pass through a bacterium-trapping filter. 3 Viruses can replicate within plant cells, so their ability to cause disease remains undiluted after several transfers from one healthy plant to another. A 1 only B 1 and 2 C 2 and 3 D 1, 2 and 3 3. Filtered sap was rubbed onto the leaves of healthy plants. 4. Healthy plants became infected 1. Sap was extracted from a diseased plant. 2. Sap was then passed through a porcelain filter known to trap bacteria.

4 © Hwa Chong Institution 2018 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 3 In an experiment, potato cylinders were placed in sucrose solutions of different concentrations. The potato cylinders were measured before and after immersion into each sucrose solution. The graph shows the effect of different sucrose concentrations on the length of the potato cylinders. When the sucrose solution was less than 0.3 mol dm -3, water molecules moved from a region of …1… negative water potential to a region of …2… negative water potential. Hence, water molecules moved from the ...3… into the …4…. If the initial length of the potato cylinder in 0.1 mol dm -3 sucrose solution is 5.0 cm, the final length will be …5…cm. Which words correctly fill gaps 1, 2, 3, 4 and 5? 1 2 3 4 5 A less more sucrose solution potato cells 5.5 B less more sucrose solution potato cells 4.5 C more less potato cells sucrose solution 5.5 D more less sucrose solution potato cells 4.5 ratio of initial length to final length of potato cylinders 0.1 0.2 0.3 0