2020 EJC Promo JC1 P1 Bio (A)

©EJC 2020 9744/01/J1H2PROMO/2020 [Turn over EUNOIA JUNIOR COLLEGE JC1 Promotional Examinations 2020 General Certificate of Education Advanced Level Higher 2 H2 Biology Paper 1 Multiple Choice 9744/01 02 October 2020 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use paper clips, glue or correction fluid. Write your name, civics group and registration number on the Answer Sheet in the spaces provided. There are thirty Multiple Choice Questions in 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. Read the instructions on the Answer Sheet very carefully. 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 an approved scientific calculator is expected, where appropriate. This document consists of 21 printed pages and 1 blank page.

2 ©EJC 2020 9744/01/J1H2PROMO/2020 BLANK PAGE

3 ©EJC 2020 9744/0J1H2PROMO/2020 [Turn over 1 Both -amylase and -amylase can hydrolyse -1,4-glycosidic bonds, but not -1,6-glycosidic bonds. -amylase acts randomly within polysaccharides and can produce glucose, maltose, trisaccharides and short, branched chains. -amylase acts at the ends of polysaccharides to produce maltose molecules. Which of the following statements about polysaccharide digestion is correct? A Both -amylase and -amylase are needed for the complete digestion of starch to produce only glucose molecules. B Digestion of amylose by -amylase will produce branched molecules only. C Digestion of amylose using -amylase will yield a higher proportion of disaccharides than digestion using -amylase. D Disaccharides can be produced from the digestion of cellulose using -amylase, but not -amylase. 2 The table below shows the percentages of carbon, hydrogen and oxygen atoms in molecules X, Y and Z. molecule % carbon % hydrogen % oxygen X 25.0 50.0 25.0 Y 28.5 47.7 23.8 Z 34.6 61.6 3.8 Which row correctly identifies molecules X, Y and Z? X Y Z A monosaccharide disaccharide polysaccharide B monosaccharide polysaccharide triglyceride C polysaccharide triglyceride monosaccharide D triglyceride monosaccharide polysaccharide

4 ©EJC 2020 9744/01/J1H2PROMO/2020 3 Threonylvaline is a dipeptide formed from two amino acids, valine and threonine. A peptide bond forms between the amino group of valine and carboxyl group of threonine. The R groups of the two amino acids are shown. Which of the following is the molecular structure of threonylvaline? A B C D

5 ©EJC 2020 9744/0J1H2PROMO/2020 [Turn over 4 The diagram shows the structure of HLA-DR1, which is a cell surface membrane receptor. HLA-DR1 consists of two polypeptides. Parts of the protein are labelled P, Q and R. Which of the following statements about HLA-DR1 is not true? A In the formation of structure P, peptide bonds are formed between adjacent amino acids via condensation reactions. B Q is important for the folding of the polypeptide into a specific 3D conformation. C Structure R is formed by hydrogen bonding between R groups. D Structures P, Q and R play a role in the formation of the quaternary structure of HLA-DR1.

6 ©EJC 2020 9744/01/J1H2PROMO/2020 5 Lactose is a disaccharide present in milk. 5 cm3 of 1% β-galactosidase solution was added to 10 cm 3 of milk. The graph shows the total amount of glucose produced over ten minutes. Which of the following graphs would be obtained when 5 cm3 of a 2% β-galactosidase solution is added to 5 cm3 of milk?

7 ©EJC 2020 9744/0J1H2PROMO/2020 [Turn over 6 The diagram shows electron micrographs of four organelles under different magnifications. Which row correctly identifies the functions of these organelles? I II III IV A attachment of carbohydrate group to protein folding of secretory proteins compartmentalises hydrolytic enzymes to prevent autolysis increases surface area for synthesis of carbohydrates B folding of secretory proteins increases surface area for synthesis of carbohydrates attachment of carbohydrate group to protein synthesis of lysosomes C synthesis of lysosomes compartmentalises hydrolytic enzymes to prevent autolysis folding of secretory proteins increases surface area for synthesis of carbohydrates D folding of secretory proteins compartmentalises hydrolytic enzymes to prevent autolysis synthesis of lysosomes attachment of carbohydrate group to protein

8 ©EJC 2020 9744/01/J1H2PROMO/2020 7 Differential centrifugation is carried out to separate cell structures in animal cells. A sample of cells was lysed to release the cell structures before the extract was filtered into a centrifuge tube and spun in a centrifuge. The diagram below shows the centrifuge tube after the first round of centrifugation. The liquid above pellet 1 was poured into a clean centrifuge tube and spun in the centrifuge at a higher speed to obtain pellet 2. This procedure was repeated two more times to obtain pellet 3 and pellet 4. Which row correctly indicates the order in which the cell structures were collected? pellet 1 pellet 2 pellet 3 pellet 4 A nucleus mitochondria lysosomes ribosomes B nucleus lysosomes mitochondria ribosomes C ribosomes lysosomes mitochondria nucleus D ribosomes mitochondria lysosomes nucleus

9 ©EJC 2020 9744/0J1H2PROMO/2020 [Turn over 8 The diagram shows the constituent biomolecules in a cell membrane. Which row correctly identifies the functions of two of the labelled molecules? molecule function molecule function A 1 allows tissue formation 4 regulates the fluidity of the membrane B 2 acts as an receptor 5 active transport C 3 facilitated diffusion 4 regulates the fluidity of the membrane D 6 bulk transport 5 acts as an enzyme

10 ©EJC 2020 9744/01/J1H2PROMO/2020 9 Glucose Transporter (GLUT-1) is a carrier protein in the cell surface membrane of cells throughout the body. The diagram below illustrates its mechanism in transporting glucose. The following statements were made. 1 As g lucose is a polar molecule, it cannot diffuse directly across the cell surface membrane. 2 There is a net movement of glucose molecules from A to B through the hydrophilic pore of GLUT-1. 3 GLUT-1 pumps glucose across the membrane via active transport. 4 GLUT-1 undergoes conformational changes upon binding of glucose at its binding site. Which of the following statements are incorrect? A 1 and 4 B 1 and 3 C 2 and 4 D 2 and 3