CJC 2023 JC2 Bio P2 (QP)

NAME: ___________________________________________ CLASS: _________ INDEX: __________ CATHOLIC JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION Higher 2 BIOLOGY 9744/02 STRUCTURED QUESTIONS 21 August 2023 2 hours READ THESE INSTRUCTIONS FIRST Write your name (as per NRIC), class, and index number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. [PILOT FRIXION ERASABLE PENS ARE NOT ALLOWED] You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. The number of marks is given in brackets [ ] at the end of each question or part question. There are 11 questions with multiple subparts in this paper. Answer all questions in the spaces provided on the Question Paper. This document consists of 28 printed pages and 2 blank pages. [ T u r n o v e r ] For Examiner’s Use Total 100 1 2 3 4 5 6 7 8 9 10 11

2 2023 Prelim/ 9744/ 02 Answer all questions 1 (a) Thermotoga maritima is a hyperthermophilic species of bacterium that lives in hot springs and thermal vents associated with volcanic activities. The bacteria can survive in waters at 80°C. Two amino acids found in the primary structure of an enzyme in the bacterium are shown below: Fig. 1.1 (i) Part of the sequence of amino acids in the enzyme consist of Cys-His. Draw a labelled diagram of the dipeptide that would result during this condensation. [2] (ii) “Cysteine is found to be more common than most other amino acids in the Thermotoga maritima enzyme compared to those found in other species”. Suggest why this may be so. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. ………..…………………………………………………………………………………………………… ………………….……………………………………………………………………………………… [2]

3 2023 Prelim/ 9744/ 02 (b) Fig. 1.2 shows an example of one of the enzymes in Thermotoga maritima. Fig. 1.2 With reference to the enzyme shown in Fig. 1.2, (i) state the highest level of protein structure. ………..………………………………………………………………………………………………... [1] (ii) identify the predominant secondary structure. ………..………………………………………………………………………………………………... [1] (iii) describe how the structure of this enzyme is maintained by various bonds. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. ………..…………………………………………………………………………………………………… …………………..………………………………………………………………………………………… ………..…………………...…………………………………………………………………………… [3]

4 2023 Prelim/ 9744/ 02 (c) Fig. 1.3 shows the effect of ATP on enzymatic activity of the enzyme found in Thermotoga maritima. Fig. 1.3 (i) With reference to Fig. 1.3, state the type of inhibition ATP exerts on the enzyme from Thermotoga maritime. Explain how you derived at your answer. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. ………..………………………………………………………………………………………………... [2] (ii) With reference to Fig. 1.3, describe the effects of ATP on enzymatic activity of Thermotoga maritima. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. ………..………………………………………………………………………………….…………….. [3] [Total: 14]

5 2023 Prelim/ 9744/ 02 [BLANK PAGE]

6 2023 Prelim/ 9744/ 02 2 Glucose transporter type 4 (GLUT4) is an example of a carrier protein that transports glucose across the plasma membrane of muscle cells. Fig. 2.1 below illustrates the steps involved in the transport of glucose by GLUT4 across the plasma membrane of a muscle cell. Fig. 2.1 With reference to Fig. 2.1, (a) name the type of transport that is used to transport glucose across the plasma membrane. ………………………………………………………………………………………………………………... [1] (b) provide two reasons for your answer in part (a). ……………………………………………………………………………………………………………........... …………………………………………………………………………………………………………………… ….……………………………………………………………………………………………………………...... ……..…………………………………………………………………………………………………………. [2] (c) explain how glucose is transported across the plasma membrane by GLUT4. ……………………………………………………………………………………………………………........... …………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………........... ………………………………………………………………………………………………………………... [2]

7 2023 Prelim/ 9744/ 02 (d) Region X is the extracellular fluid and Region Y is the cytoplasm of a muscle cell. Do you agree? Justify your answer. …………………………………………………………………………………………………………………… ………………………………………………………………… ……………………………………………... [1] An experiment was conducted to investigate the effect of glucose concentration on the rate of movement of glucose across the plasma membrane of muscle cells. (e) Based on the information in Fig.2.1, sketch a graph of the result of the experiment. [1] Explain your answer: …………………………………………………………………………………………………………………… ………………………………………………………………… ……………………………………………... [1] [Total: 8]

8 2023 Prelim/ 9744/ 02 3 (a) State how one structural feature of DNA contributes to its stability as a hereditary material. ….……………………………………………………………………………………………………………...... ……..…………………………………………………………………………………………………………. [1] The “trombone” model of DNA replication postulates that two DNA polymerase enzymes work together in a protein complex during DNA replication. Fig. 3.1 shows a DNA molecule undergoing DNA replication. Fig. 3.1 (b) With reference to Fig. 3.1, (i) compare how the synthesis of the lagging strand differs from that of the leading strand. …………………………………………………………………………………………………………..… ….……………………………………………………………………………………………………….… ….………………………………………………………………………………………….……………… ……..………………………………………………………………………………………….….……. [2] DNA ligase DNA polymerases helicase primase

9 2023 Prelim/ 9744/ 02 (ii) suggest why it is necessary for two DNA polymerase enzymes to work together in a protein complex during DNA replication. ….……………………………………………………………………………………………………….… ….……………………………………………………………………………………………………….… ….………………………………………………………………………………………..………………... ………..…………………………………………………………………………………..……………. [2] (c) Explain how the end replication problem arises. …………………………………………………………………………………………………………………… ….………………………………………………………… …………………………………………………...... ….………………………………………………………… …………………………………………………...... ……..…………………………………………………………………………………………………………. [2] [Total: 7] 4 Nucleolus is a large and dense region inside the nucleus. It consists of a fibrous part and a granular part. The large and small ribosomal subunits can be found within the granular part. (a) Based on the information above as well as your knowledge on transcription and translation, outline how ribosomes are formed. …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… ….………………………………………………………… …………………………………………………...... …………………………………………………………………………………………………………………… …………………………………………………………………………………………