NYGH 2020-S3EOY-Bio P2A

Class Register Number Name 南洋女子中学校 NANYANG GIRLS’ HIGH SCHOOL End of Year Examination 2020 Secondary Three IP IP BIOLOGY Paper 2 Theory Paper 1 hour 45 minutes Monday 12 October 2020 1015 – 1200 Additional materials: Nil 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 two questions. Question 10 is in the form of an Either/Or question. Only one part should be answered. Tick 10 Either or 10 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 (4 marks) 3 (5 marks) 4 (7 marks) 5 (7 marks) 6 (7 marks) 7 (5 marks) Section B (30 marks) 8 (10 marks) 9 (10 marks) tick: 10 Either (10 marks) tick: 10 Or (10 marks) TOTAL (100 marks) Setters: TZZ This document consists of 12 printed pages. NANYANG GIRLS’ HIGH SCHOOL [Turn over A

2020 End-of-Year Examination Secondary Three IP 2 Nanyang Girls’ High School IP Biology Section A (40 marks) Answer all questions. Write your answers in the spaces provided. 1 Fig. 1.1 is an electron micrograph showing part of a cell. magnification x 10 000 Fig. 1.1 D E A B C centriole

2020 End-of-Year Examination Secondary Three IP 3 Nanyang Girls’ High School IP Biology [Turn over (a) Name the structures labelled A and C. State their functions. A: ……………………………………. function of A: ………………………………………………………………………………………….. ………………………………………………………………………………………….. C: ……………………………………. function of C: ………………………………………………………………………………………….. ………………………………………………………………………………………….. [2] (b) B is a mitochondrion. Suggest why the mitochondria seen in Fig 1.1 are of different shapes. ………………………………………………………………………………………….. ………………………………………………………………………………………….. [1] (c) Calculate the actual length of DE, in cm, in Fig. 1.1. In your working, write down the formula used to make your calculation. Show your working clearly. actual length of DE = ………………………. cm [2] [total: 5]

2020 End-of-Year Examination Secondary Three IP 4 Nanyang Girls’ High School IP Biology 2 Fig. 2.1 is a photomicrograph of root tip cells at various stages of mitosis. Fig. 2.1 https://www.researchgate.net/figure/Chromosomal-aberrations (a) Identify the stages of cell division shown in cell J and K. cell J ………………………………………………………………………………………….. cell K …………………………………………………………………………………............. [1] (b) Describe the changes occurring from the stage shown in cell K to the stage shown in J. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ………………………………………………………………………………………….. [3] [total: 4] K J

2020 End-of-Year Examination Secondary Three IP 5 Nanyang Girls’ High School IP Biology [Turn over 3 (a) (i) Define mutation. …………………………………………………………………………………... …………………………………………………………………………………... [1] (ii) State two ways in which mutation rate can be increased. ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… [2] Fig. 3.1 shows the chromosomes from two infants, infant A and infant B. infant A infant B Fig. 3.1 (b) State two differences in terms of numbers and types of chromosomes between the two infants. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… [2] [total: 5]

2020 End-of-Year Examination Secondary Three IP 6 Nanyang Girls’ High School IP Biology 4 Duchenne Muscular Dystrophy is a genetic disorder characterised by progressive weakening of muscles. The disorder is due to the absence of a key protein found in muscles called dystrophin. The gene that codes for this protein is found on the X chromosome. (a) Using a genetic diagram, show how two parents who do not suffer from the disorder can have children who have Duchenne Muscular Dystrophy. [5] (b) (i) State the probability that a daughter born to this couple will be a carrier for Duchenne Muscular Dystrophy. …………………………………………………………………………………... [1] (ii) The couple have three daughters and when screened, none of them were carriers for the disorder. Explain why this is so. …………………………………………………………………………………... …………………………………………………………………………………... [1] [total: 7]

2020 End-of-Year Examination Secondary Three IP 7 Nanyang Girls’ High School IP Biology [Turn over 5 Fig. 5.1 shows the release of digestive enzymes from a small intestinal cell. Fig. 5.1 (a) Suggest why there are no protein transporters for the movement of these digestive enzymes. ………………………………………………………………………………………… ………………………………………………………………………………………… [1] (b) Name and describe the process that allows the digestive enzymes to cross the membrane. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… [2]

2020 End-of-Year Examination Secondary Three IP 8 Nanyang Girls’ High School IP Biology (c) A student conducted an investigation on osmosis in Chinese Leek. The stem of the plant has a hollow centre. The student cut strips from the stem of the plant as show in Fig 5.2. Fig. 5.2 A strip was placed in 1 % salt solution and 5 % salt solution for thirty minutes. The results are shown in Fig. 5.3. epidermis cortex tissue strip cut from the stem strip placed in 1 % salt solution strip placed in 5 % salt solution Fig. 5.3

2020 End-of-Year Examination Secondary Three IP 9 Nanyang Girls’ High School IP Biology [Turn over A strip was placed in distilled water for the same duration. (i) In Fig. 5.4, draw the appearance of the strip in the box provided. Clearly label the epidermis and cortex in your drawing. [1] (ii) Explain the appearance of the Chinese Leek you have drawn in Fig. 5.4. ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… [3]