MEMORANDUM GRADE 11. LIFE SCIENCES: Half-year exam

Transcription

1 MEMORANDUM GRADE 11 LIFE SCIENCES: Half-year exam MARKS: 150 TIME: 2½ hours

2 Section A Question D B C C B (5 2) [10] pericycle Casparian band ball-and-socket joint osteoarthritis or arthritis pericardium [5] C A A D C (5 2) [10] copper extraction (1) rock containing copper (1) Thiobacillus converts copper sulfide into copper sulfate. Thiobacillus converts inactive iron back into active iron. (2) Monera (1) Sulfur dioxide is a pollutant that causes acid rain. It also causes asthma and bronchitis and irritates people s eyes, noses and throats. When using the bacteria, no sulfur dioxide is produced. (any 2) MEMORANDUM: Maskew Miller Longman, Focus on Life Sciences Grade 11 Half-year exam Page 2 of 9

3 1.4.6 gold (1) cheese-making, vinegar-making, sewage treatment (any 2) [10] kidney (1) A Bowman s capsule B glomerulus C Malpighian body D proximal convoluted tubule (4) a) A and B b) E (3) [8] approximately 20 kpa (2) Higher. Blood is pumped under high pressure from the ventricles into the aorta. The aorta is a smaller structure so the blood pressure will rise slightly. (2) Less than 0 kpa. During general diastole the atria are relaxed, so the blood pressure is low. (2) during ventricular systole (1) [7] Total Question 1: 50 marks Total Section A: 50 marks MEMORANDUM: Maskew Miller Longman, Focus on Life Sciences Grade 11 Half-year exam Page 3 of 9

4 Section B Question The aorta carries oxygenated blood from the heart to the rest of the body. (3) Arteries Capillaries The walls consist of three layers. Blood flows through at high pressure. The artery wall is impermeable. Red blood cells can move through the artery side by side. Arteries carry blood away from the heart. The walls consist of a single layer of endothelium. Blood passes through slowly at low pressure. Substances can move through the capillary walls. Red blood cells flow through in single file. Capillaries connect arteries to veins. (Learners can give any two differences. Subtract two marks if an answer is not tabulated.) (4) Veins have valves. Valves prevent the backflow of blood. Blood flows through veins at low pressure. (3) The initiation of a small child into a clan, the rites of passage into adulthood and the marriage ceremony all centre around blood. Blood is a symbol of the ancestors. Blood entering the body allows the ancestors to enter the body, guiding and protecting the person. To ensure that newborn children have bonds with their fathers, a small piece of their umbilical cords, containing a small amount of blood, are kept and dried out. The fathers swallow the dried-out pieces of cord. OR any other African traditions centred round blood. (any 4) [14] MEMORANDUM: Maskew Miller Longman, Focus on Life Sciences Grade 11 Half-year exam Page 4 of 9

5 2.2.1 animal A hydrostatic skeleton animal B exoskeleton (2) Hydrostatic skeleton Exoskeleton Advantage The animals do not require any support structures or tissues. The skeleton serves as support and protection. Disadvantage The animal is limited in the size it can reach and the speed it can move. The animal is limited in the size it can reach because it becomes very heavy. (4) [6] Fungi have no roots, stems or leaves. Most fungi are made of branching filaments (threads) with no conducting tissue. Fungi have no chlorophyll and are heterotrophic. The cell walls of fungi are made of chitin and not cellulose. Fungi store carbohydrates as glycogen and not starch. (any 3) a) It has a lower alcohol content. (1) b) The yeast uses the sugar in the sorghum for respiration. This takes place in the absence of oxygen and results in fermentation, which produces alcohol and carbon dioxide. (3) c) The women skim off the froth and use it for baking. They use the yeast to make dumplings called ujeje. (1) d) The grain that remains in the sieve is used as food for pigs and to attract termites. The people eat termites as a source of fats and protein in their diets. (any 2) [10] Total Question 2: 30 marks MEMORANDUM: Maskew Miller Longman, Focus on Life Sciences Grade 11 Half-year exam Page 5 of 9

6 Question Limpopo (1) Malaria will only occur in regions where the Anopheles mosquito, which carries the parasite, occurs. (2) Plasmodium vivax (1) flu-like symptoms about days after infection with the parasite 2. high temperature and fever 3. shivering and sweating (3) As the parasite reproduces, the new parasites invade more red blood cells. The patient s temperature rises as the parasites invade the red blood cells. When the cells burst, the patient contracts a fever and alternately shivers and sweats. This process repeats itself. (3) destroying the mosquitoes 2. prevention of mosquito bites (2) The malaria parasite reproduces rapidly. Genetic changes or mutations make the parasite resistant to chloroquinine. These parasites then survive treatment by chloroquinine. The surviving parasites that are resistant to chloroquinine rapidly increase in numbers. (4) [16] a) There is protein present. (1) b) The Malpighian body must be damaged. The membranes are allowing the large protein molecules to pass from the glomerulus into the Bowman s capsule. This could be due to kidney disease or injury. (3) a) individual B (1) b) There is glucose present in the urine. (1) MEMORANDUM: Maskew Miller Longman, Focus on Life Sciences Grade 11 Half-year exam Page 6 of 9

7 3.2.3 The evidence is that there is a decrease in the amount of water and an increase in salts in the urine. The osmotic pressure in the blood increases after individual C has eaten salty potato chips. This stimulates the release of ADH from the pituitary gland. ADH makes the collecting ducts of the kidneys more permeable to water. More water is reabsorbed into the body. There is too much salt in the blood. This stimulates the release of aldosterone from the adrenal glands. Aldosterone stimulates tubular secretion of the excess salts. These salts are then excreted in the urine. The release of ADH and aldosterone both help to reduce the osmotic pressure of the blood. (8) [14] Total Question 3: 30 marks Total Section B: 60 marks MEMORANDUM: Maskew Miller Longman, Focus on Life Sciences Grade 11 Half-year exam Page 7 of 9

8 Section C Question The faster the air movement, the higher the rate of transpiration. OR The faster the air movement, the greater the water loss from the plant. OR The more windy the conditions, the higher the rate of transpiration. OR any other similar, correct hypothesis. (2) a) the rate of transpiration (1) b) wind speed or air movement (1) c) Leafy twig, distance between the fan and the leafy twig, time (any 2) (4) Place the potometer on a level surface. 2. Make sure the potometer is airtight and watertight. 3. Cut the stem of the leafy twig under the water to prevent air blocking the xylem vessels. 4. Allow a time period to elapse before taking new readings. (any 2) Bar graph to show the change in the rate of transpiration at different wind speeds Fan speed setting is off. The experiment is set up in the same way but there is no air movement. (2) Air blows over the leaf. It removes the thin layer of water vapour that forms on the leaf surface. This increases the diffusion gradient between the leaf and the atmosphere. The rate of diffusion or transpiration therefore increases. (3) [20] (7) MEMORANDUM: Maskew Miller Longman, Focus on Life Sciences Grade 11 Half-year exam Page 8 of 9

9 4.2 Classification of joints There are three kinds of joints: 1. fibrous joints, which are immoveable joints 2. cartilaginous joints, which are slightly moveable joints 3. synovial joints, which are moveable joints. (3) The role of cartilage, ligaments and tendons in movable joints Cartilage: Synovial or movable joints are made of hyaline cartilage. Cartilage is very strong, but also flexible and elastic. The function of cartilage in joints is to reduce friction between the bones of the joints. Ligaments: Bones are held together by ligaments. Ligaments control the range of motion of a joint. Ligaments help keep joints stable and prevent bones from moving out of position during body movement. Tendons: Tendons attach muscles to bone. The body moves when a muscle pulls a bone. (7) Antagonistic muscles and joint movement The skeleton and muscles work together to allow movement. When muscles contract they pull the bones. The muscles then relax. Muscles always work together in antagonistic pairs to bring about movement. This means that they work against each other. When one muscle contracts, the other muscle relaxes. (4) Description of the contraction of voluntary muscle tissue Each muscle fibre is made of smaller units called myofibrils. The myofibrils consist of protein filaments. The two muscle proteins are actin and myosin. The myosin filaments are slightly thicker than the actin filaments. When a skeletal muscle contracts, the actin filaments in the myofibrils slide inwards between the myosin filaments. This shortens the sarcomeres or myofibril sub-units. Each muscle fibre is made of many sarcomeres, so when they all shorten together, the whole muscle fibre shortens or contracts. (6) Note: Award no marks for answers that are given as flow charts or diagrams. [20] Total Question 4: 40 marks Total Section C: 40 marks Grand total: 150 marks MEMORANDUM: Maskew Miller Longman, Focus on Life Sciences Grade 11 Half-year exam Page 9 of 9