SCGS 2017 Bio Prelim P2 QP

1 CANDIDATE NAME CLASS 4 INDEX NUMBER BIOLOGY Paper 2 Theory 5158/02 1 hour 45 minutes READ THESE INSTRUCTIONS FIRST Write your class, index number and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid/tape. Section A Answer all questions. Section B Answer all questions, the last question has a choice of parts to answer. The use of an approved scientific calculator is expected, where appropriate. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. This question paper consists of 29 printed pages. SINGAPORE CHINESE GIRLS’ SCHOOL Preliminary Examination Secondary Four For Examiner’s Use Section A 50 Section B 30 Total 80 Tuesday 1 August 2017 1 hour 45 minutes

2 Section A Answer all the questions. Write your answers in the spaces provided. 1 (a) Name a constituent of a diet that is [1] (i) absorbed without digestion, ……………………………………………… (ii) never absorbed. ……………………………………………… Fig. 1.1 is a diagrammatic representation of the small intestine containing three types of food molecules, A, B and C before they have been fully digested. Fig. 1.1 also shows a lacteal and a capillary, both not drawn to scale. Fig. 1.1 (b) On Fig. 1.1, draw and label the molecules as they would appear after they have been fully digested and then absorbed by the lacteal and by the blood capillary. [1] A B C

3 (c) Some of these molecules travel directly to the liver. Name two molecules and explain how they are transported to the liver. [2] …………………………………………………………………………………………. …………………………………………………………………………………………. (d) Describe how A is completely digested by named enzymes in the small intestine. [2] …………………………………………………………………………………………. …………………………………………………………………………………………. [Total : 6m]

4 2 Fig. 2.1 shows a large jar in which plants are growing. Fig. 2.1 This jar provides an environment in which plants can carry out photosynthesis without adding water or removing the tightly-fitting cork to allow air to enter. (a) State the word equation for photosynthesis in the space below. [1] (b) Describe how the plants in Fig. 2.1 obtain water in the jar. [2] …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. (c) Suggest a reason, apart from limited carbon dioxide, why the plants in the jar show only very limited growth compared with similar plants growing under natural conditions. [1] …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. A B C unsterilized soil clear glass jar tightly-fitting cork

5 (d) State an advantage of using unsterilized soil for the plants. [1] …………………………………………………………………………………………. …………………………………………………………………………………………. [Total : 5m]

6 3 Fig. 3.1 shows changes in the volume of blood in the left ventricle. Fig. 3.1 (a) Between which times is the left atrium contracting? [1] …………………………………………………………………………………………. (b) Using information from Fig. 3.1, calculate the number of heart beats per minute. Show your working. [1] ……………………. (c) On Fig. 3.1, label the point ‘X’ where the ‘lub’ sound of the heart is produced. [1] Time / s Volume / cm3

7 Table 3.1 shows the rate of blood flow to some organs when a person is at rest and during a period of vigorous exercise. Table 3.1 Organ Rate of blood flow / cm3 minute -1 at rest during exercise Skeletal muscles 1 000 16 000 Kidney 1 200 1 200 Brain 750 Heart muscle 300 1 200 (d) Suggest a value for the rate of blood flow to the brain during exercise. [1] …………………………………………………………………………………………. (e) Using information from Table 3.1, calculate the ratio of the rate of blood flow into the coronary arteries during exercise to the rate flowing into these arteries at rest. [1] …………………………………………………………………………………………. [Total : 5m]

8 4 Table 4.1 shows the relative thickness of layers in the walls of an artery and a vein. Table 4.1 (a) Using information from Table 4.1, explain why a vein may be described as an organ. [1] …………………………………………………………………………………………. …………………………………………………………………………………………. (b) Use information from Table 4.1 to suggest the thickness of a capillary wall. [1] …………………………………………………………………………………………. (c) Explain how the elastic tissue in the wall helps to even out the pressure of blood flowing through the artery. [1] …………………………………………………………………………………………. …………………………………………………………………………………………. Layer in wall Thickness / µm artery vein Endothelium 20 20 Smooth muscle 490 240 Elastic tissue 370 240 Connective tissue 120 120

9 Fig. 4.1 shows part of a capillary and some of the cells surrounding it. Fig. 4.1 (d) Describe the transfer of materials between Fluid X and Fluid Y. Identify X and Y in your answer. [2] ............................................................................................................................ …………………………………………………………………………………………. ............................................................................................................................ …………………………………………………………………………………………. [Total : 5m] From artery To vein Fluid X Fluid Y

10 5 Fig. 5.1 shows how the branch of a small apple tree varied in diameter over a 24- hour period. Fig. 5.1 (a) Using the data given in the table below, draw a curve on the grid above to show how rate of transpiration of the apple tree varied over the same 24-hour period. [1] Time / h Rate of transpiration / arbitrary units (AU) 0 24 6 5 12 30 18 40 24 25 Diameter of branch (A.U.) Rate of transpiration (A.U.) 10 20 30 40