Biology 0610/43 May/June 2019: question paper and mark scheme

Question

Bacteria are classified in the Prokaryote kingdom. (a) State two features of animal cells that are not found in bacteria. 1 …… 2 …… [2] (b) The bacterium Bacillus megaterium was grown in the laboratory fermenter shown in Fig. 1.1. air lock water sterile air magnetic stirrer bacteria, source of nitrogen and glucose Fig. 1.1 (i) Explain why a source of nitrogen and glucose were added to the fermenter. nitrogen …… glucose …… [2] (ii) Suggest why it is important to stir the contents of the fermenter continuously. …… [3] (c) Samples were taken from the fermenter at frequent intervals and the number of live bacteria was determined. The results are shown in Fig. 1.2. 800 C 700 600 500 number of live bacteria D 400 / million per cm3 B 300 200 100 A 0 0 10 20 30 40 50 60 time / hours Fig. 1.2 Describe and explain what happens to the number of live bacteria shown in the stages labelled A, B, C and D in Fig. 1.2. …… [6] [Total: 13]

Question

(a) State the word equation for photosynthesis. …… [2] (b) Scientists investigated the effect of light intensity on the rate of photosynthesis in the leaves of eucalyptus trees at two different concentrations of carbon dioxide, A and B. The results are shown in Fig. 2.1. rate of photosynthesis / μmol per m2 per s 50 45 B 40 35 30 25 A 20 15 10 5 0 0 250 500 750 1000 1250 1500 1750 2000 light intensity / arbitrary units Key: A carbon dioxide concentration 140 ppm B carbon dioxide concentration 1000 ppm Fig. 2.1 (i) Suggest and explain why the scientists kept the temperature of the leaves at 20 °C while they recorded results. …… [2] (ii) Calculate the percentage increase in the rate of photosynthesis at a light intensity of 1250 arbitrary units when the carbon dioxide concentration was increased from 140 ppm to 1000 ppm. Show your working and give your answer to the nearest whole number. …… % [3] (iii) Describe the effect of increasing light intensity on the rate of photosynthesis when the concentration of carbon dioxide was 140 ppm. …… [3] (iv) Explain the effect of increasing light intensity on the rate of photosynthesis when the concentration of carbon dioxide was 1000 ppm. Use the term limiting factor in your answer. …… [4] [Total: 14]

Question

Cotton, Gossypium hirsutum, is grown for the fibres that form within the fruits after fertilisation, as shown in Fig. 3.1. Fibres from the fruits of cotton plants are used in the textile industry. fibres Fig. 3.1 Cotton plants have been genetically engineered to produce a protein that is toxic to the caterpillars of several insect pests. This gives the cotton plants resistance to the pests. The cry gene for pest resistance was isolated from the bacterium Bacillus thuringiensis and inserted into the cells of cotton plants as shown in Fig. 3.2. cry gene A A bacterial DNA plasmid cotton plant cell not to scale Fig. 3.2 (a) An enzyme cuts the cry gene from the DNA of B. thuringiensis. (i) State the name of the enzyme that cuts DNA. …… [1] (ii) State the name of the regions labelled A on Fig. 3.2. …… [1] (iii) Explain how the DNA is inserted into the plasmid. …… [3] (b) The plasmids containing the cry gene are inserted into the cells of cotton plants. Outline how the cells of cotton plants use the cry gene to make the toxic protein. …… [4] (c) Outline the advantages to farmers of growing genetically engineered cotton plants that contain the toxic protein. …… [3] [Total: 12]

Question

Mammals have a double circulation. (a) State what is meant by the term double circulation. …… [1] (b) Table 4.1 shows some information about the functions of the components of blood. Complete Table 4.1. Table 4.1 function type of cell production of antibodies phagocyte promotes blood clotting transports oxygen [4] (c) Blood is transported in arteries and veins. Complete the drawings of the cross-sections of an artery and a vein to show the differences between these two types of blood vessel. Label the lumen in each drawing. artery vein [2] (d) A diagram of a mammalian heart and associated blood vessels is shown in Fig. 4.1. A L B C K J D E H F G Fig. 4.1 (i) Sketch arrows on Fig. 4.1 to show the pathway taken by deoxygenated blood from the heart towards the lungs. [2] (ii) Table 4.2 contains statements about the structures visible in Fig. 4.1. Complete Table 4.2 by: • stating the name of each structure • identifying the structure with the corresponding letter from Fig. 4.1. Table 4.2 statement name of structure letter from Fig. 4.1 chamber that creates the highest blood pressure blood vessel containing blood with the highest concentration of oxygen structure that prevents blood going from ventricle to atrium structure that prevents backflow of blood from artery to ventricle chamber that receives blood from vena cava [5] (e) Mammals also have a lymphatic system. Outline the functions of the lymphatic system. …… [3] [Total: 17]

Question

Sickle-cell anaemia is an inherited disease. Fig. 5.1 is a photomicrograph of some blood cells from a person who has sickle-cell anaemia. a sickle-shaped red blood cell Fig. 5.1 (a) Explain how red blood cells become sickle-shaped. …… [3] (b) Some people who have sickle-cell anaemia have parents who do not have sickle-cell anaemia. Explain how people with sickle-cell anaemia inherit the disease. …… [4] (c) Sickle-cell anaemia is most common in areas of the world where the infectious disease malaria is found. Some species of the genus Plasmodium cause malaria in humans. (i) Define the term species. …… [2] (ii) The distribution of sickle-cell anaemia is the result of natural selection. Explain the distribution of the sickle-cell allele in human populations. …… [5] [Total: 14]

Question

Fig. 6.1 is a photomicrograph of part of a cell from the pancreas that produces enzymes that are released into the small intestine. S P R Q ×20 000 Fig. 6.1 (a) (i) Structure Q is part of the nucleus of the cell. State one function of a nucleus. …… [1] (ii) State the names of the structures labelled P and R in Fig. 6.1. P …… R …… [2] (b) The structure labelled S transports enzymes to the cell membrane for release into the pancreatic duct. These structures contain molecules of amylase, trypsin and lipase. Complete the sentences with the most appropriate words. Enzymes are made of protein and act as …… because they increase the rate of chemical reactions, but are not changed in those reactions. Amylase speeds up the digestion of …… to …… Trypsin continues the chemical digestion of protein begun by the enzyme …… in the stomach. The optimum pH for pancreatic enzymes is greater than pH 7. Bile is produced by the …… and enters the small intestine, where it …… stomach acid to provide the appropriate pH. Bile also breaks down fat by …… to increase the surface area for the action of lipase. [7] [Total: 10]