9 . G11 LifeSciences DigitalSupport web Practice Examination Paper 1 Memo

Study & Master Support Pack | Grade 11 CAPS Life Sciences Practice examination: Paper 1 memo This support pack consists of a memorandum of answers for Paper 1 of the Life Sciences Grade 11 CAPS curriculum so that you or the learners can check their answers and asses their readiness for the examinations. You have permission to print or photocopy this document or distribute it electronically via email or WhatsApp. Cambridge University Press Africa is a proudly South African publisher. For more information on our Study & Master CAPS-approved textbooks and valuable resource materials, visit www.cambridge.org Brighter thinking | Better learning Practice Examinations Paper 1: Memo www.cambridge.org

Life Sciences Examination: Exemplar Paper 1 Section B QUESTION 2 Memorandum of answers 2.1.1 A – afferent arteriole Marks: 150 D – Bowman’s capsule Time: 2 ½ Hours E – renal tubule (3) 2.1.2 Creates a high pressure in the glomerulus High pressure makes ultra-filtration possible (2) Section A 2.1.3 C – blood QUESTION 1 D – glomerular filtrate (2) 1.1 2.1.4 A (1) 1.1.1 d 2.1.5 • C contains blood cells 1.1.2 c • D does not contain blood cells 1.1.3 b OR 1.1.4 c • C contains blood proteins 1.1.5 a (5 × 2) [10] • D does not contain blood proteins (2) 2.1.6 • when the heart pumps slower 1.2 • this lowers the blood pressure 1.2.1 chlorophyll • this reduces ultra-filtration 1.2.2 photosynthesis OR 1.2.3 dark phase • less blood reaches the kidneys 1.2.4 iodine • and less oxygen and nutrients get to the kidneys 1.2.5 ATP • less cellular respiration takes place in the kidney cells 1.2.6 stroma (6 × 1) [6] • and kidneys cannot carry on functioning (3) 2.1.7 cuboidal epithelium (1) 1.3 [14] 1.3.1 a only 1.3.2 Both a and b 2.2 1.3.3 a only 2.2.1 To destarch it/no starch present at the start of the 1.3.4 Both a and b experiment (2) 1.3.5 Both a and b (5 × 2) [10] 2.2.2 To prevent light from falling on covered part/shade the part from light/to serve as a control (2) 1.4 2.2.3 1.4.1 B – renal vein exposed part turns blue-black F – urethra (2) 1.4.2 proteins glucose covered part turns brown vitamins amino acids glycerol/fatty acids (any three) (3) (3) 1.4.3 stores urine temporarily (1) [7] 1.4.4 excretion 2.3 osmoregulation 2.3.1 100 × 5 500 regulates pH 2 000 regulates salt concentration = 275 g (0,275 kg) (3) (any three)   (3) 2.3.2 [9] 1.5 protein 1.5.1 A – oesophagus E – rectum fats F – appendix carbohydrates H – gall bladder (4) 1.5.2 a C b B c G d H (4) [8] Correct type of graph 1 1.6 1.6.1 A – larynx Correct proportions/% 4×1=4 B – bronchus Label / key for each slice 4×1=4 D – diaphragm F – intercostal muscles (4) Title 1 1.6.2 a reduces friction during breathing (1) (10) b keeps bronchus open at all times (1) [13] c moistens/cleans/removes foreign bodies (1) [7] Total Section A: [50] Practice Examinations Paper 1: Memo

2.4 3.3 2.4.1 a digestion/hydrolysis 3.3.1 60–69 years (1) b absorption (2) 3.3.2 80+ years (1) 2.4.2 water acts as a solvent to dissolve the nutrients 3.3.3 • The prevalence of diabetes increases with age. • it facilitates easy diffusion between the absorptive • The prevalence of diabetes is greater in women surface (2) than in men. (4) 2.4.3 villi (1) 3.3.4 It is greater in women. (1) 2.4.4 amino acids (1) 3.3.5 • Women may be more prone to abdominal obesity. 2.4.5 • excess amino acids (molecules C) cannot be stored • Hormonal changes after menopause may make in the body women more prone to diabetes. (4) • they are broken down in the liver [11] • by the process of deamination 3.4 • into glucose and urea 3.4.1 The higher the altitude, the greater the average • glucose is oxidised to release energy number of red blood cells per volume of blood. (2) • while the urea is excreted by the kidneys 3.4.2 Taking an average of results minimises the error factor (mark TWO only) (2) that is found when only one result is used. (2) [8] 3.4.3 For the shorter distance races like the 800 m, there is 2.5 • Capillaries branching from the pulmonary artery carry no significant difference in the time. However, for the deoxygenated blood to the lungs longer distances like the 5 000 m and 10 000 m, there • The concentration of carbon dioxide in the capillaries is a significant difference at higher altitudes and the is higher than that of the air of the alveoli running time becomes longer. (2) • This concentration gradient causes carbon dioxide to 3.4.4 The longer distance events – e.g. 5 000 m and 10 000 m (2) diffuse from the blood through the endothelial wall of 3.4.5 Many of these athletes are acclimatised to high altitudes. the capillaries Hence their bodies were already adjusted to the lower • And through the squamous epithelia of the alveolus oxygen content of the air. A person who normally lives at and into the alveolus a height of over 1 000 m differs from a person who lives • Carbon dioxide is expelled from the lungs during below 300 m in the following ways: exhalation • His/her breathing is deeper. • The oxygen content of the inhaled air is greater in the • The volume of his/her blood increases from about alveolus than in the capillaries 5–6,5 litres. • Oxygen dissolves in the moisture lining the alveolus • The number of red blood cells in his/her blood and diffuses through the squamous epithelia of the increases from about 5 million per mm3 to about alveolus wall 7 million per mm 3. • And through the endothelial wall of the capillary into Hence, these athletes suffered less muscle fatigue because of the blood plasma their ability to pay off their oxygen debt and were therefore • Most of the oxygen combines with haemoglobin of more successful. (2) the erythrocytes to form oxyhaemoglobin and is [10] transported in this form to the tissues. [10] 3.5 3.5.1 There is a linear or directly proportional relationship, i.e. Total Question 2: [50] the level of ADH rises and tubular reabsorption increases proportionally. (2) QUESTION 3 3.5.2 Increased ADH has the following effect on the renal tubules: • A DH increases the number of water-selective channels 3.1 Cellular respiration Breathing Gaseous exchange in the plasma membrane of the distal convoluted A chemical process A mechanical A physical process that tubule and the collecting duct. that takes place process that involves the diffusion of • This increases the permeability of the cell membranes in the cells. This involves the intake gases across membranes to water. involves the of oxygen into (gas exchange surfaces), for • This causes more water to leave the tubules by osmosis breakdown of fuel the lungs and the example between the air and to enter the medulla of the kidney. molecules to release release of carbon the blood in the lungs and • The water in the medulla is reabsorbed by the blood energy (ATP), water dioxide from the between the blood and other capillaries that surround the tubule (peritubular and carbon dioxide. lungs. tissues in the body. capillaries). • The amount of water in the blood increases, so more [6] concentrated urine is produced and less water is excreted from the body. (2) 3.2 3.5.3 If the body is losing a lot of water through sweat, more 3.2.1 a I is a chloroplast, II is a mitochondrion. (2) ADH will be produced to compensate and so reduce the b A is O2, B is CO2 (2) amount of water lost in urine. In hot conditions, less and c I is photosynthesis, II is cellular respiration. (2) more concentrated urine is produced than on a cold day. If d energy and water (1) a person is not able to drink for a long period of time, high 3.2.2 • It has folded cristae that increase the surface area ADH levels will conserve as much water as possible and the available for enzyme action. volume of urine will be reduced. (2) • The outer membrane is smooth and permeable, 3.5.4 ADH levels may be low on a cold day because: allowing substances such as ions and pyruvic acid • Very little water is lost through sweat. to enter and ATP molecules to leave. (4) • The kidney will need to lose more water to maintain [11] water balance and so less ADH is secreted. (2) Practice Examinations Paper 1: Memo

3.5.5 Salt balance is maintained by the uptake of sodium ions in the loop of Henle, which is controlled by the hormone aldosterone (produced in the adrenal cortex). The adrenal cortex is under the control of the pituitary gland, which detects salt levels in the blood and stimulates the adrenal cortex to produce the necessary amount of aldosterone. (4) [12] Total Question 3: [50] Total Section B: [100] TOTAL: [150] Practice Examinations Paper 1: Memo