WA4 Mock BT P1 (Teacher)

1 Civics Group Index Number Name (use BLOCK LETTERS) ST. ANDREW’S JUNIOR COLLEGE 2022 JC2 Weighted Assessment 4 H1 BIOLOGY 8876/01 Paper 1: Multiple Choice 50 min Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, civics group and index number on the multiple choice answer sheet in the spaces provided. There are 25 questions in this paper. Answer all questions. For each qu estion, 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 multiple choice Optical answer sheet. INFORMATION TO CANDIDATES Each correct answer will score one mark. A mark will not be deducted for wrong answer. Any rough working should be done in this booklet. At the end of the examination, submit both question paper and multiple choice answer sheet. This document consists of 19 printed pages [Turn over H1

2 1 The electron micrograph below shows an organelle. Which of the following statements about the labelled structures are correct? 1. X serves to compartmentalise the organelle from the extracellular environment. 2. X is made up of a phospholipid bilayer and it is selectively permeable to substances. 3. Y has embedded proteins containing chlorophyll that are involved in the absorption of light. 4. Y has embedded ATP synthase that synthesizes ATP. 5. Z contains linear double-stranded DNA. 6. Z contains glycolytic enzymes that oxidises glucose to pyruvate. A 2 and 4 B 5 and 6 C 1, 2 and 4 D 1, 3 and 6 2 Cells can be ruptured and their contents collected after a series of centrifugation at different speeds. At the end of every centrifugation set at a specific speed, a pellet containing specific organelles is formed. The supernatant is then centrifuged at a higher speed than pr eviously and the new pellet formed collected. The process is repeated as outlined in the following diagram.

3 The sequence of pellets obtained in tubes 1, 2, 3 and 4 would be A ribosomes, endoplasmic reticulum, mitochondria, nuclei. B ribosomes, mitochondria, nuclei, endoplasmic reticulum. C nuclei, mitochondria, endoplasmic reticulum, ribosomes. D nuclei, endoplasmic reticulum, ribosomes, mitochondria. 3 The diagram below illustrates the process of phloem loading with the help of proteins 1 and 2. Which of the following accurately describes the type of transport occurring at proteins 1 and 2? Protein 1 Protein 2 A Simple diffusion Active transport B Active transport Facilitated diffusion C Facilitated diffusion Facilitated diffusion

4 D Active transport Simple diffusion Explanation Transport proteins are required, hence simple diffusion should be eliminated 🡪 Only active transport and facilitated diffusion are possible. Protein 1: Transport of H+ is against concentration gradient and requires ATP 🡪 Active transport Protein 2: Transport of H+ is down concentration gradient and requires transport protein 🡪 Facilitated diffusion. 4 The graph below shows the amount of product formed in an enzyme-catalysed reaction over a certain period of time at 37° C. What is true at time X? A Most enzyme molecules will have free active sites. B The number of unreacted substrate molecules is high. C The number of enzyme-substrate complexes is low. D The rate of enzymatic reaction is low. 5 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 molecular structure is threonylvaline?

5 A B C D 6 Which one of the following statements about haemoglobin is correct? A Haemoglobin structure contains both α helices and β pleated sheets B Haemoglobin has a quartenary protein structure with 4 identical subunits C Haemoglobin structure involves hydrogen, ionic, disulfide bonds and hydrophobic interactions D Haemoglobin contains 4 non-prosthetic heme groups 7 The diagram summarizes the process of photosynthesis.

6 Which row identifies the reactants 1, 2, 3, 4 and 5? 1 2 3 4 5 A carbon dioxide ADP + phosphate reduced NAD NAD water B carbon dioxide reduced NADP ADP + phosphate NADP water C water NAD reduced NAD ADP + phosphate carbon dioxide D water NADP ADP + phosphate reduced NADP carbon dioxide 8 In an experiment, metabolically active cells were added to a container of nutrient solution. The container was then sealed. The graph shows the levels of glucose, carbon dioxide and oxygen over two continuous time intervals, X and Y. Which of the following can be concluded from the graph?

7 A The experiment is carried out on yeast cells. Fermentation occurs during interval X while aerobic respiration occurs during interval Y. B The experiment is carried out on animal cells. Aerobic respiration occurs during interval X while anaerobic respiration occurs during interval Y. C The experiment is carried out on yeast cells. Aerobic respiration occurs during interval X while fermentation occurs during interval Y D The experiment is carried out on animal cells. Anaerobic respiration occurs during interval X while aerobic respiration occurs during interval Y. 9 Trematol is a metabolic poison derived from the white snake root. Cows eating this plant concentrate the poison in their milk. The poison inhibits liver enzymes that convert lactate to other compounds for metabolism. Which row illustrates the events that occur in an exercising athlete who consumed the trematol-tainted milk? lactate accumulation NAD production ATP production pH of blood A yes yes yes decreased B no yes yes decreased C yes no no increased D no no no increased 10 The graph shows changes in the amount of DNA during one cell cycle. The letters U – Z marks out the different phases in the cell cycle.

8 Name the events occurring at W, X and Y. W X Y A S phase Anaphase Telophase B Fertilisation Interphase Cytokinesis C S phase Prophase Cytokinesis D Fertilisation Metaphase Telophase 11 The photomicrograph shows cells in different stages of mitosis.

9 Which statements are correct? 1. Stage T shows metaphase. 2. DNA replication is occurring during stage R. 3. A cell in stage P and a cell in stage T have the same amount of DNA. 4. The correct order for the stages of mitosis is S → R →T →P →Q. A A 1 and 4 B B 2 and 4 C C 1, 2 and 3 D D 1, 3 and 4 12 A fisherman was surprised to catch a fish which had no scales (nude). To investigate the origin of this phenotype, the nude fish was mated several times to fish with scales and the result of each cross was recorded. In the crosses of nude with scaled, a third phenotype appeared, which was later called linear. The linear phenotype has only a single line of scales down one side of the body. The outcomes of these crosses are shown in the table. Cross Parents Offspring phenotype and ratio 1 scaled x nude all offspring linear 2 linear x linear 1 scaled : 2 linear : 1 nude

10 Which of the following is conclusive from the above data? A There is incomplete dominance between the nude and scaled phenotype. B The environment is the reason for the loss of scales in the nude fish. C All of the linear fish are homozygotes. D The nude fish are heterozygotes. Explanation A third phenotype is usually due to the presence of multiple alleles at a single gene, or incomplete dominance/ codominance. Key: SN ; N = Allele coding for absence of scales (nude) SS ; S = Allele coding for presence of scales Cross 1: Parental phenotype: Scaled x Nude Parental genotype: SS SS x SN SN Gametes: SS