CHS 2023 - Sec 4 BIOLOGY Prelim Exam PAPER 2 - Questions

Name: Index Number: Class: CATHOLIC HIGH SCHOOL Preliminary Examination Secondary 4 A BIOLOGY 6093/02 Paper 2 Thursday 24 August 2023 1 hour 45 minutes Additional Materials: - READ THESE INSTRUCTIONS FIRST Write your name, index number and class on all the work you hand in. Write in dark blue or black pen. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE ON THE MARGINS. Section A Answer all questions. Write your answers in the spaces provided on the Question Paper. Section B Answer all questions. Write your answers in the spaces provided on the Question Paper. Electronic calculators may be used. You are advised to spend no longer than one hour on Section A and no longer than 45 minutes on Section B. The number of marks is given in brackets [ ] at the end of each question or part question. For examiner’s use only: Section A / 50 Section B / 30 This paper consists of 19 printed pages. [Turn over

2 Section A Answer all questions. Write your answer in the spaces provided. 1 Some young grass plants were grown with their roots in a mineral solution that contained nitrate ions. The plants were divided into two batches, N and P. Cyanide, which inhibits aerobic respiration, was added to the solution given to the plants in batch P. The quantity of nitrate ions in the plants was determined at regular intervals for 70 hours. After 60 hours, the mineral solution was replaced by distilled water. The results are shown in Fig. 1.1. Fig. 1.1 Use the data in Fig. 1.1 to answer parts (a) to (c). (a) Calculate the rate of absorption of nitrate ions in batch N between 40 and 60 hours. Show your working. mg per hour [2]

3 (b) Explain why the absorption of nitrate ions by the plants in batch N differs from that in batch P; [4] (c) Explain why the mean quantity of nitrate ions in both batches of plants decreased after 60 hours. [2] [Total: 8 marks]

4 2 (a) Cartilage is present in some parts of the gas exchange system to prevent collapse due to pressure changes during inhalation. State two parts of the gas exchange system in which cartilage is located. and [1] (b) Fig. 2.1 shows the changes that occur in atmospheric pressure and oxygen concentration as altitude changes. The highest altitude at which people live permanently is 5100 m. Fig. 2.1 With reference to Fig. 2.1: (i) describe the effect of increasing altitude on both atmospheric pressure and the oxygen concentration [2] (ii) calculate the change in the atmospheric pressure when a person travels from sea level to an altitude of 3500 m. Show your working. answer [2]