Christ Church Pure Biology Prelim 2024 Paper 2

CHR 2024 / Biology 6093/02/O/24 [Turn over ok CHRIST CHURCH SECONDARY SCHOOL 2024 PRELIMINARY EXAMINATION SECONDARY FOUR EXPRESS Biology 6093/02 Paper 2 22 August 2024 1 hour 45 minutes No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, index number and class in on all the work you hand in. You may use an HB pencil for any diagrams, graphs, tables or rough working. Write in dark blue or black pen. Do not use staples, paper clips, highlighters, glue or correction fluid. The 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. Section A Answer all questions. Write your answers in the spaces provided on the question Paper. Section B Answer one question. Write your answers in the spaces provided on the question Paper. 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 document consists of 20 printed pages. For Examiner’s Use Section A Section B Total CANDIDATE NAME CLASS CENTRE NUMBER S INDEX NUMBER

2 CHR 2024 / Biology 6093/02/O/24 Section A Answer all questions in the spaces provided. 1 Fig. 1.1 shows the reproductive organs of a man who has had part X cut and tied in a surgery known as vasectomy. Fig. 1.1 (a) State two products of organ G. 1 ………………………………. 2 ………………………………. [2] (b) Name part X and explain how cutting and tying of part X means for the fertility of this man. X ………………………………. [1] explanation ……………………………………………………………………………... ……………………………………………………………………………... ……………………………………………………………………………... [2] X G

3 CHR 2024 / Biology 6093/02/O/24 [Turn over (c) A patient was diagnosed with varicocele, a condition characteri sed by the enlargement of veins within the scrotum due to malfunctioning valves inside the testicular veins. Suggest and explain how varicocele might affect the sperm production and quality. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. [4] [Total: 9]

4 CHR 2024 / Biology 6093/02/O/24 2 (a) Explain how the human gas exchange system is protected against pathogens. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. [3] (b) Tuberculosis (TB) is a n infectious disease caused by a bacterial pathogen. The spread of this disease can be controlled by vaccination. Explain how vaccination provides a defence against infectious diseases. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. [3] (c) TB is a disease that can be treated with antibiotics. Explain why viral diseases cannot be treated with antibiotics. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. [2] [Total: 8]

5 CHR 2024 / Biology 6093/02/O/24 [Turn over 3 The blood flow through the skin of some volunteers was measured with a flow-meter when their skin was exposed to different temperatures. Capsaicin is a compound that gives people the sensation of feeling hot when it is put on the skin similar to how the skin would feel warm after touching something hot like a warm cup of tea because it activates the same nerves that detect heat. Researchers applied capsaicin to the skin of the volunteers and again measured the blood flow through their skin at different temperatures. Fig. 3.1 shows the results. Fig. 3.1 (a) Use the information in Fig. 3.1 to describe the effect of increasing the temperature of the skin surface on blood flow to the skin without capsaicin. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. [3] average blood flow as a percentage of maximum blood flow temperature of the skin surface / °C without capsaicin with capsaicin

6 CHR 2024 / Biology 6093/02/O/24 (b) Explain the mechanism that increases blood flow through the skin. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. [3] (c) State the difference between the average blood flow for the treatments (with and without capsaicin) at 35°C. ……………………… % [1] (d) The researchers thought that capsaicin stimulated cells in the skin. Explain the process by which capsaicin could reach these cells. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. [3] (e) Body temperature is controlled by both hormones and nerves. Explain how co-ordination by hormones differs from co-ordination by nerves. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. [2] [Total: 12]

7 CHR 2024 / Biology 6093/02/O/24 [Turn over 4 Maple syrup urine disease (MSUD) is a rare inherited human condition caused by mutation. MSUD is caused by a recessive allele. MSUD is usually diagnosed in early childhood and can be controlled by having a low protein diet. Fig. 4.1 shows the inheritance of MSUD in one family. Fig. 4.1 (a) (i) Des