NYJC 2023 H2 Biology 9744 P1 MS

NANYANG JUNIOR COLLEGE PRELIMINARY EXAMINATIONS Higher 2 CANDIDATE NAME CLASS BIOLOGY 9744/01 Paper 1 Multiple Choice 22 September 2023 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name and CT on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. Calculators may be used. This document consists of 25 printed pages. [Turn over

9744 / H2 Biology / 01 2 1 A eukaryotic 80S ribosome consist of a 60S large and a 40S small subunit. Which sequence of events concerning ribosomes is correct? A rRNA and proteins are synthesi zed and subuni ts are formed w ithin the nucleolus . They become membrane bound as they are exported through the nuclear envelope to the cytoplasm and rough endoplasmic reticulum (rER). B rRNA and proteins assemble to form the 60S subunit in the nucleus while those of the 40S subunit are assembled independently in the cytoplasm. C rRNA is synthesized in the nucleolus and proteins are synthesized by the rough endoplasmic reticulum (rER). Subunit formation occurs within the cytoplasm for free ribosomes and on the surface of the rER for attached ribosomes. D rRNA synthesised within the nucleolus is complexed with prot eins that have been impor ted from the cytoplasm. The subunits formed are exported separately to the cytoplasm v ia the nuclear pores.

9744 / H2 Biology / 01 3 2 Human and mouse cells were fused to make hybrid cells. Anti-human and anti-mouse antibodies, carrying different coloured fluorescent dyes, were added. The antibodies bind to the protein of the cell surface membrane. The fused cells were incubated for 40 minutes. The locations of the human and mouse membrane proteins were identified at intervals using the fluorescent dyes. The diagram represents the results of the experiment by showing the positions of the human and mouse proteins on the surface of the cells. What does this experiment show? A Movement of the phospholipids pushes the membrane proteins apart. B Some membrane proteins move through the phospholipids to different places. C The phospholipids of the human and mouse cells surface membranes do not mix. D The proteins of human cell surface membranes can move further than those of mouse cells.

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