RVHS 2023 JC2 H2 Prelim P3 QP

1 RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATION CANDIDATE NAME CENTRE NUMBER S CLASS 22J INDEX NUMBER BIOLOGY 9744/03 Paper 3 Long Structured and Free-response Questions 15 September 2023 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, index number and name in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE ON ANY BARCODES. Section A Answer all questions in the spaces provided on the Question Paper. Section B Answer any one question in the spaces provided on the Question Paper. 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. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 2 3 Section B Total This document consists of 26 printed pages and 2 blank pages.

2 River Valley High School H2 Biology 9744/03 2023 JC2 Preliminary Examination Section A Answer all the questions in this section. 1 The gut microbiota is the community of all micro-organisms (bacteria, archaea, protozoa, fungi, and viruses) present in the digestive tract. Bacteria are the largest component of the microbiota. (a) Describe the structure of bacterial genome. [3]

3 River Valley High School H2 Biology 9744/03 2023 JC2 Preliminary Examination Question 1 continues on page 4

4 River Valley High School H2 Biology 9744/03 2023 JC2 Preliminary Examination Gut bacteria are present in a range of species in Kingdom Animalia including insects, fish, and apes. Gut bacteria are passed vertically from mother to offspring. Its composition and abundance have changed in the generations with evolutionary time. Fig. 1.1 shows the relative change in abundance of selected bacterial taxa in the evolution of humans (Homo sapiens). Relative change is shown by the “_x” in the box beside the descendant species, for example “5x” refers to a five times increase in abundance from the ancestor. Adapted from Moeller et al, PNAS, 111(46), 2014 Fig. 1.1 (b) With reference to the animals in Fig. 1.1, explain how phylogeny is related to classification. [2]

5 River Valley High School H2 Biology 9744/03 2023 JC2 Preliminary Examination Diet has a significant influence on gut bacteria composition. Different diets contribute different nutrients to the digestive tract which affects the presence and proportion of various bacterial genera. Chimpanzees’ (genus: Pan ) diet mainly comprise of plants and plants’ produce, with meat cont