NYGH 2021-S3EOY-IP Bio P2A

Class Register Number Name End-of-Year Examination 2021 Secondary Three IP BIOLOGY Paper 2 1 hour 45 minutes Thursday 7 October 2021 0845 – 1030 READ THESE INSTRUCTIONS FIRST Do not open this document until you are told to do so. Write your name, register number and class in the spaces at the top of this page. Section A Answer all questions. Write your answers in the spaces provided on the question paper. Section B Answer three questions. Question 11 is in the form of an Either/Or question. Only one part should be answered. Tick 11 Either or 11 Or in the grid-box on the cover page to indicate the question answered. The intended number of marks is given in the brackets [ ] at the end of each question or part question. The use of an approved scientific calculator is expected, where appropriate EXAMINER’S USE Paper 1 (30 marks) Paper 2 Section A (40 marks) 1 (5 marks) 2 (5 marks) 3 (5 marks) 4 (4 marks) 5 (5 marks) 6 (4 marks) 7 (7 marks) 8 (5 marks) Section B (30 marks) 9 (10 marks) 10 (10 marks) tick: 11 Either (10 marks) tick: 11 Or (10 marks) TOTAL (100 marks) Setters: LZJ, TZZ This document consists of 15 printed pages and 1 blank page NANYANG GIRLS’ HIGH SCHOOL [Turn over A

2021 End-of-Year Examination Secondary Three IP 2 Nanyang Girls’ High School IP Biology 1 Fig. 1.1 shows an electron micrograph of part of a cell from the liver of a mouse. x 47 500 Fig. 1.1 (a) Calculate the actual length of the mitochondrion, represented by line XY, in micrometres (µm). Show your working clearly in the space provided. Give your answer to 2 decimal places. [2] XY Z

2021 End-of-Year Examination Secondary Three IP 3 Nanyang Girls’ High School IP Biology [Turn over (b) The liver carries out detoxification which requires a variety of enzymes. Suggest why large numbers of mitochondria and Z are required in a liver cell. ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………..…………………………………….……………..[3] [Total:5]

2021 End-of-Year Examination Secondary Three IP 4 Nanyang Girls’ High School IP Biology 2 Deoxyribonucleic acid (DNA) contains genes that store genetic information. (a) Define the term gene. ……………………………………………………………………………………….…………………… ……………………………………………………..…………………………………….……………..[1] (b) A DNA molecule was found to contain 30% of adenine. State the percentage of cytosine in the same DNA molecule. ……………………………………………………..…………………………………….……………..[1] (c) About 85 % of the DNA of a mouse is the same as that of a human. Use ideas about the function of DNA and genes to suggest why mice are very different in appearance to humans. ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………..…………………………………….……………..[2] (d) Genetic engineering can be used to manipulate the genes of organisms. Suggest one social or ethical implication of genetic engineering in plants. ……………………………………………………………………………………….…………………… ……………………………………………………..…………………………………….……………..[1] [Total: 5]

2021 End-of-Year Examination Secondary Three IP 5 Nanyang Girls’ High School IP Biology [Turn over 3 Drosophila is a fruit fly that is commonly used in genetic research. They can be easily bred and grown in the laboratory. The diet of the Drosophila fruit fly consists of banana, yeast and maize. Females can lay on average 100 eggs at once and it takes 24 hours for the eggs to hatch. The life cycle of the fruit fly, from egg fertilisation to adult is 10 days. The maximum lifespan of a Drosophila fruit fly is about 80 days. Fig. 3.1 shows two varieties of the Drosophila fruit fly. Fig. 3.1 (a) Suggest a reason why Drosophila fruit flies are often used in genetic experiments. ……………………………………………………………………………………….…………………… ……………………………………………………..…………………………………….……………..[1] with normal wings with vestigial wings 3 mm 2 mm

2021 End-of-Year Examination Secondary Three IP 6 Nanyang Girls’ High School IP Biology (b) In an experiment, two Drosophila fruit flies with normal wings were allowed to mate. Table 3.1 shows the variety and number of offspring obtained. Table 3.1 variety numbers normal wings 80 vestigial wings 25 Using a genetic diagram, explain the results of the experiment. [4] [Total: 5]

2021 End-of-Year Examination Secondary Three IP 7 Nanyang Girls’ High School IP Biology [Turn over 4 Fig. 4.1 shows movements that take place within a cell during mitosis. 0 marks the time when chromosomes line up on the equator of the cell. Fig. 4.1 (a) The following statements describe the change in distance between some structures in the cell over a period of 30 minutes. Match the curves A, B and C correctly to the change in distance between the structures. curve descriptions change in distance between centromeres of sister chromatids change in distance between centromeres and poles of the spindle change in distance between the poles of the cell [1] (b) With reference to Fig. 4.1 describe what happens to the sister chromatids after 15 minutes. ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………..…………………………………….……………..[2] time/ min distance/ µm A B C 60 50 40 30 20 10 0 0 5 10 15 20 25 30

2021 End-of-Year Examination Secondary Three IP 8 Nanyang Girls’ High School IP Biology Remainder of this page is intentionally left blank (b) Describe what happens to the chromatids after 30 mins. ……………………………………………………………………………………….…………………… ……………………………………………………..…………………………………….……………..[1] [Total: 4]

2021 End-of-Year Examination Secondary Three IP 9 Nanyang Girls’ High School IP Biology [Turn over 5 Fig. 5.1 illustrates a section of the fluid mosaic model of a cell surface membrane. Fig. 5.1 (a) On Fig. 5.1, label and name one structure which allow glucose molecules to move across the cell surface membrane. [1] (b) Describe what is meant by the term fluid mosaic. ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….…………………… ……………………………………………………………………………………….……………………