2024 ASRJC H2 Bio P1 QP

ASRJC BIOLOGY DEPT 9744/2024/J2PRELIMS/P1 [Turn over 2024 JC2 PRELIMINARY EXAMINATIONS BIOLOGY 9744/01 PAPER 1 13 SEPTEMBER 2024 MULTIPLE CHOICE FRIDAY 1 HOUR Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, class and identification number on the MCQ Answer Sheet. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of scientific calculators is expected, where appropriate. This document consists of 23 printed pages and 1 blank page. H2 ANDERSON SERANGOON JUNIOR COLLEGE HIGHER 2

2 ASRJC BIOLOGY DEPT 9744//2024/J2PRELIMS/P1 1 What can be found in both eukaryotic and prokaryotic cells? 1 circular DNA 2 lipids 3 ribose 4 peptidoglycan cell wall A 1, 2 and 3 B 1, 2 and 4 C 2 and 3 D 3 and 4 2 Hydroxyproline is a component of collagen. The graph shows the effect of temperature on the triple helix structure of collagen with and without hydroxyproline. The y-axis of the graph indicates the percentage of intact triple helix structure in a sample of collagen. Which statement(s) explain(s) the importance of hydroxyproline in the structure of collagen? 1 Presence of hydroxyproline increases thermal stability of collagen as hydroxyproline facilitates formation of covalent cross-links within each triple helix structure. 2 At higher temperatures, collagen with hydroxyproline results in less triple helices present than collagen without hydroxyproline. 3 Hydroxyproline contributes to the extensive hydrogen bonds that hold the polypeptide chains of each triple helix structure. A 1 only B 3 only C 1 and 2 D 2 and 3 collagen without hydroxyproline collagen with hydroxyproline temperature / °C triple helix structure / % key

3 ASRJC BIOLOGY DEPT 9744//2024/J2PRELIMS/P1 [Turn over 3 One way of representing fatty acid chains is Cx : y, where Cx is the number of carbon atoms and y is the number of double bonds. The table shows the percentage mass of eight different fatty acid chains found in four cell membranes, P, Q, R and S. cell membrane percentage mass of each fatty acid chain in the cell membrane C10 : 0 C12 : 0 C14 : 0 C16 : 0 C18 : 0 C18 : 1 C18 : 2 C18 : 3 P 1 2 2 21 35 29 2 1 Q 2 23 19 45 3 1 R 2 3 23 21 43 4 S 1 2 4 22 2 52 11 1 Which of the following about the four cell membranes (P, Q, R and S) is correct? most fluid least fluid A R P B R Q C S Q D S P

4 ASRJC BIOLOGY DEPT 9744//2024/J2PRELIMS/P1 4 Catechol is oxidised to benzoquinone, as shown in the equation, resulting in darkening of peeled fruits. Catechol oxidase is an enzyme which is inhibited by p arahydroxybenzoic acid (PHBA), which is structurally similar to catechol. Catechol oxidase is also inhibited by phenylthiourea (PTU) which binds to a copper atom in the enzyme. The copper atom is essential for the oxidative activity. The graph shows the rate of the reaction with and without PTU. Which of the following statement(s) is/ are not correct? 1 PHBA acts as a competitive inhibitor because its structure is similar to benzoquinone. 2 PHBA acts as a competitive inhibitor, and in the presence of PHBA, the maximum velocity of the reaction cannot be restored by increasing the concentration of catechol. 3 PTU acts as a non-competitive inhibitor, preventing the formation of enzyme-substrate complex between catechol oxidase, catechol and O2. A 2 only B 3 only C 1 and 2 D 2 and 3 ½ O2

5 ASRJC BIOLOGY DEPT 9744//2024/J2PRELIMS/P1 [Turn over 5 Some descriptions of possible similarities between two different cell types in an individual are listed. 1 They have identical genotypes. 2 They can divide repeatedly by mitosis. 3 They have the same ability to differentiate into different cell types. Within an individual organism with cancer, which of these possible similarities would be expected to be true when comparing tumour cells with multipotent stem cells? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only 6 The ends of a eukaryotic chromosome contain a special sequence of DNA called a telomere. Human telomeres consist of repeating TTAGGG sequences. When cells undergo mitotic division, some of these repeating sequences are lost. This results in the shortening of telomeric DNA. What is a consequence of the loss of repeating DNA sequences from the telomeres? A The cell will begin the synthesis of different proteins. B The cell will begin to differentiate as a result of the altered DNA. C The number of mitotic divisions the cell can undergo will be limited. D The production of mRNA will be reduced.

6 ASRJC BIOLOGY DEPT 9744//2024/J2PRELIMS/P1 7 The diagram below shows events occurring during the synthesis of a protein that is secreted from a cell. Which statements correctly describe the process shown? 1 During amino acid activation, lysine is likely to be attached to molecule X and the coupling reaction is cataly sed by a group of enzymes called aminoacyl -tRNA synthetases. 2 Peptidyl transferase in the large subunit of ribosome catalyses the formation of bond Y. 3 The tRNA carrying the leucine amino acid is occupying the P site of the large subunit of the ribosome. 4 The sequences of the DNA bases on template strand that code for amino acid Z is AAT. 5 The codon UAU is closer to the poly A tail of the mRNA. A 1 and 3 B 1, 2 and 5 C 1, 4 and 5 D 2, 3 and 4

7 ASRJC BIOLOGY DEPT 9744//2024/J2PRELIMS/P1 [Turn over 8 Four processes that involved nucleic acids are shown in the diagram below. Which features of these processes are represented by K, L and M? K L M A hydrogen bonds are broken DNA as template strand enzymes are involved B phosphodiester bonds are broken template is read in 3’ to 5’ direction can involve all three RNAs C primers are required phosphodiester bonds are formed template is read in 5’ to 3’ direction D double-stranded DNA denatures happen in the nucleus only complementary base- pairing occurs 9 ‘Viruses are not considered to be living organisms.’ Which state