NYGH 2018-S3EOY-IP Bio P1 and P2 Ans

2018 End-of-Year Examination Secondary Three 1 Nanyang Girls’ High School IP Biology [Turn Over 南洋女子中学校 NANYANG GIRLS’ HIGH SCHOOL End-of-Year Examination 2018 Secondary Three IP BIOLOGY Answers with Explanation and Feedback PAPER 1 [30 Marks] MCQ Answer 1 C 2 B 3 A 4 B 5 D 6 B 7 D 8 A 9 C 10 D 11 A 12 A 13 C 14 A 15 A 16 C 17 A 18 B 19 B 20 D 21 B 22 D 23 C 24 A 25 B 26 B 27 B 28 A 29 C 30 C

2018 End-of-Year Examination Secondary Three 2 Nanyang Girls’ High School PAPER 2 / SECTION A [30 Marks] Q 1 Answer Guidance (a) C red blood cell (reject: red blood cells) D fibrin (thread / fibre) (accept: plural) (b) Damaged tissue and platelets release (reject: form) thrombokinase. In presence of calcium ions (reject: calcium), thrombokinase activates prothrombin into thrombin. Thrombin converts soluble fibrinogen into insoluble fibrin which trap/entangle red blood cells. (c) Blood carrying glucose and oxygen will not be transported to heart cells / tissues for respiration. Heart muscles cannot contract / die / damaged, and heart stops pumping / heart attack results. [Total: 7] Q 2 Answer Guidance (a) lactase lactose glucose + galactose (b) (i) W untreated milk X milk treated with lactase immediately before drinking Y milk treated with lactase two days before drinking Z yoghurt made by bacteria that hydrolysed the lactose in the milk (b) (ii) Patients could suffer from: dehydration / loss of water (molecules)/ lack of water absorbed loss / poor absorption of nutrients / nutrients not absorbed/ be malnutrition. (b) (iii) Concentration of hydrogen gas in the exhaled air present is the lowest / least with exhaled air [1] between 9 to 15 (± 1) ppm / not higher than 15 (± 1) ppm. [quote data [1]] Concentration of hydrogen gas in the exhaled air presence has small fluctuations / changes over 5 hours.

2018 End-of-Year Examination Secondary Three 3 Nanyang Girls’ High School IP Biology [Turn Over (c) Villus has one-cell thick epithelium/ walls of villus is one-cell thick to reduce distance for diffusion / active transport of nutrients / digested food / named. Villus has microvilli to increase surface area to volume ratio for faster diffusion / active transport. Villus has dense / rich network of blood capillaries to transport (dissolved) nutrients / digested food / named quickly from the digestive system. [Total: 8] Q 3 Answer Guidance (a) Golgi apparatus has flattened sacs with layered appearance / no connection between membranes. Golgi apparatus is not connected / contiguous / connected with (outer membrane) of nuclear envelope. Golgi apparatus has swellings / vesicle formation at ends of sacs. No ribosomes are attached to the Golgi apparatus. (b) More cholesterol among the phospholipid layer. Higher proportion of phospholipids with saturated fatty acids / lesser kinks in fatty acids (chains). Lesser transport / named (channel / carrier) protein. (c) (i) Ribosomes attached to / on the rough endoplasmic reticulum are the sites for protein / polypeptide synthesis / condensation of amino acids. (c) (ii) Radioactivity first shows an increase of 55% within 5 minutes, and a decrease of 40% within 35 minutes. Transport vesicles containing radioactive proteins (Reject amino acids) move from rough endoplasmic reticulum to the Golgi apparatus, causing the increase. Golgi apparatus chemically modify and packaged the radioactive proteins into secretory vesicles, which then bud off from the Golgi apparatus, causing the decrease. [Total: 7]

2018 End-of-Year Examination Secondary Three 4 Nanyang Girls’ High School IP Biology [Turn Over Q 4 Answer Guidance (a) The movement of chloride ions from inside cell with a higher concentration to outside cell with a lower concentration. This movement across membrane requires transport / channel / carrier protein. (b) No (build-up) of chloride ions on the opposite side of membrane / outside cell / extracellularly. Water potential outside cell will be less negative in cystic fibrosis person / than a normal person / ora. No (net) movement of water molecules across the (selectively permeable) membrane / no osmosis from surrounding (environment) to the mucus. Hence, mucus becomes more concentrated with less water present / ora. (c) Pancreatic juice / named enzyme is not released / secreted into the duodenum / small intestine, hence (chemical) digestion / hydrolysis of food will occur slowly. (d) The percentages for all three species of bacteria add up to more than 100%. The data could represent repeated counts of patient. [Total: 9]

2018 End-of-Year Examination Secondary Three 5 Nanyang Girls’ High School IP Biology [Turn Over Q 5 Answer Guidance (a) Draw: phloem (left-side) + xylem (right-side) Label: phloem + xylem (b) sucrose (c) Transpiration involves evaporation of water for the continuous diffusion of water vapour through stomata in leaves that reduces (hydrostatic) pressure at the top of plant, resulting in transpiration pull. Water transported continuously up the xylem (vessel) is maintained by cohesion between water molecules and adhesion of water to xylem walls. (d) (i) liver (d) (ii) Alcohol dehydrogenase will hydrolyse alcohol / ethanol into acetaldehyde / ethanal. (d) (iii) Excessive alcohol consumption increases reaction time / reduced self-control / acts as depressant / AW. Excessive alcohol consumption increases risks for liver damage / named (cirrhosis, cancer) / gastric ulcers / (relevant) negative social implications / AW. [Total: 9] PAPER 2 / SECTION B [30 Marks] Q 6 Answer Guidance (a) (i) Size (at least 75% of gridlines) Plotting of points for A and B Lines for A and B (with labelled lines) Axes: Y-axis (number of bubbles released in one minute) X-axis (time / min) Title: Graph to show the number of bubbles released in one minute against time / min

2018 End-of-Year Examination Secondary Three 6 Nanyang Girls’ High School IP Biology [Turn Over graph plot – example (a) (ii) description The number of bubbles released in a minute increases with time from 0 to 20 for A and 0 to 10 for B. The released bubbles / foam formation in A is faster / more i.e. 10 bubbles / 2.5cm thicker (than B) / ora. explanation Aerobic respiration occurs in A but anaerobic respiration occurs in B. The rate of carbon dioxide gas released in aerobic respiration is higher than anaerobic respiration / ora. (b) Glucose / substrate is used up, hence no further / lower rate of respiration. Warm water cools down causing lower (effective) collisions between enzymes and substrates / lower rate of enzyme-substrate complex formation / substrate binding to active site of enzymes. [Total: 10] number of bubbles released in one minute time / min 20 15 10 5 0 5 10 15 20 A B 0

2018 End-of-Year Examination Secondary Three 7 Nanyang Girls’ High School IP Biology [Turn Over Q 7 Answer Guidance (a) light + chlorophyll 6 CO2 + 6 H2O C6H12O6 + 6 O2 (b) Removes / hydrolyse the sugar-phosphate group from active site of rubisco. (c) Both photosynthesis and photorespiration share the same enzyme (rubisco) and one of the reactants (RuBP). There is competition for the enzyme and reactant, hence when the rate of one process decrease, the other will increase. High light intensity increases the rate of photolysis, hence producing more oxygen, leading to an increase in the rate of photorespiration. High light intensity causes stomata to open and more oxygen to diffuse into the leaves. More RuBP combined with oxygen. (d) (i) graph shape Rate of photosynthesis increase as temperature increase towards optimum + Rate of photosynthesis decrease sharply beyond optimum temperature. (d) (ii) Increase in tempe