2022 JC2 H1 BT P1 annotated answers

Civics Group Index Number Name (use BLOCK LETTERS) ST. ANDREW’S JUNIOR COLLEGE 2022 JC2 BLOCK TEST H1 BIOLOGY 8876/1 Paper 1: Multiple Choice Thursday 7th July 2022 1 hour Additional Materials: Multiple Choice Answer Sheet Soft clean eraser (not supplied) Soft pencil (type B or HB is recommended) READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, civics group and index number on the multiple choice answer sheet in the spaces provided. There are 30 questions in 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 multiple choice answer sheet. INFORMATION TO CANDIDATES Each correct answer will score one mark. A mark will not be deducted for wrong answer. Any rough working should be done in this booklet. At the end of the examination, submit both question paper and multiple choice answer sheet. This document consists of 19 printed pages. [Turn over H1

2 SAJC / H2 Biology 9744/1 JC2 BT 2022 1 A scientist carried out an experiment to separate cell structures in animal cells. The cells were lysed to release the cell structures. This extract was transferred into a centrifuge tube and then spun in a centrifuge. The heaviest cell structure sank to the bottom, forming pellet 1, as shown in the diagram. The liquid above pellet 1 was poured into a clean centrifuge tube and spun in the centrifuge at a higher speed to separate the next heaviest cell structure. This cell structure sank to the bottom, forming pellet 2. This procedure was repeated twice more to obtain pellet 3 and pellet 4, each containing a single type of cell structure. Which row shows the order in which the cell structures were collected? Pellet 1 Pellet 2 Pellet 3 Pellet 4 A Nucleus Lysosomes Mitochondria Ribosomes B Nucleus Mitochondria Lysosomes Ribosomes C Ribosomes Lysosomes Mitochondria Nucleus D Ribosomes Mitochondria Lysosomes Nucleus Explanation: Pellet 1 should contain the largest cell organelle (nucleus) and cell debris Students should work from pellet 4 backwards to figure out the cell structures in pellet 3 and 2 respectively Pellet 4 should contain ribosomes (smallest organelle) Hence Pellet 2 contains mitochondria (ave size 0.5–3m) and Pellet 3 contains lysosomes (ave size 0.1–1.2 m)

3 SAJC / H2 Biology 9744/1 JC2 BT 2022 2 The figure below shows an electron micrograph with two plant cells. Which of the following statements correctly describe the labelled structures? 1. R contains circular DNA and is found in both prokaryotic and eukaryotic cells. 2. P has a fluid mosaic structure and regulates the movement of substances between the two plant cells. 3. S acts as a selective permeable barrier. 4. Q contains enzymes which