Biology 0610/43 May/June 2020: question paper and mark scheme

Question

(a) State three uses of energy in the human body. 1 …… 2 …… 3 …… [3] (b) Fig. 1.1 shows part of the digestive system of a human. A diaphragm B L K C H G D F E Fig. 1.1 Complete Table 1.1. One row has been done for you. Table 1.1 function name of structure letter from Fig. 1.1 pushes food to the stomach oesophagus A assimilation of amino acids to produce plasma proteins storage of bile secretion of insulin absorption of fatty acids and glycerol secretion of pepsin digestion of starch [6] (c) Describe the role of the liver in the recovery from oxygen debt after strenuous exercise. …… [2] (d) Alcohol is a drug. Define the term drug. …… [2] (e) (i) State two immediate effects of excessive alcohol on the body. 1 …… 2 …… [2] (ii) State two long-term effects of excessive alcohol on the body. 1 …… 2 …… [2] (f) Pregnant women are advised not to drink alcohol as it may have harmful effects on the fetus. (i) Outline these harmful effects. …… [2] (ii) State two harmful substances other than alcohol that can cross the placenta. 1 …… 2 …… [2] [Total: 21]

Question

(a) Fig. 2.1 shows the human population of a country between 1910 and 2020. 140 120 100 number of people 80 / million 60 40 20 0 1900 1920 1940 1960 1980 2000 2020 year Fig. 2.1 (i) Calculate the percentage increase in the population of the country between 1940 and 2020. Space for working. ……% [3] (ii) Describe the factors that could cause the change in the population size between 1940 and 2020, shown in Fig. 2.1. …… [3] (b) Some countries have invested in biofuels such as ethanol, biomass and biodiesel. (i) Describe how ethanol can be made by microorganisms. …… [2] (ii) Some countries use large areas of land to grow maize plants. This crop plant can be used to produce biofuels. Discuss the negative impact on the environment of growing large-scale monocultures of crop plants such as maize. …… [4] [Total: 12]

Question

The American writer Ernest Hemingway lived on the island of Key West in Florida, USA in the 1930s. During this time he was given a male cat by a sea captain. The cat had more toes than usual. This inherited condition is called polydactyly. The allele for polydactyly is dominant. (a) Define the term inheritance. …… [1] (b) Fig. 3.1 is part of a pedigree diagram for Hemingway’s cats. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Key: 17 female cat with normal female cat with number of toes polydactyly male cat with normal male cat with number of toes polydactyly Fig. 3.1 (i) State the genotypes of cats 5, 6 and 14 in the pedigree diagram in Fig. 3.1. Use the letters T and t. cat 5 …… cat 6 …… cat 14 …… [3] (ii) Explain why none of the offspring of cats 3 and 4 have inherited polydactyly. Use the information in Fig. 3.1 in your answer. …… [1] (c) Scientists published the results of an investigation into the DNA of cats with and without polydactyly. They compared the base sequence from a particular region of DNA that controls the development of the limbs. Table 3.1 shows the base sequences. Table 3.1 cats without polydactyly AGA CAC AGA AAT GAG Hemingway’s cats with polydactyly AGA CAC GGA AAT GAG cats with polydactyly from Oregon and Missouri in the USA AGA CAC GGA AAT GAG cats with polydactyly from the UK AGA CAC AGT AAT GAG (i) Describe how the base sequences of the cats with polydactyly differ from the base sequence of cats without polydactyly. …… [2] (ii) State the name of the process by which base sequences in DNA are changed. …… [1] (iii) The base sequences in Table 3.1 provide evidence that indicates which country the male cat given to Hemingway in the 1930s came from. Suggest which country this cat came from and give a reason for your choice. …… [2] (d) Fig. 3.2 shows part of a DNA molecule from a chromosome of a cat. Complete Fig. 3.2 by writing the letters for the base sequence of the other strand of the DNA molecule. T …… A …… A …… T …… G …… C …… G …… T …… G …… Fig. 3.2 [1] (e) Explain why polydactyly is an example of discontinuous variation. …… [2] [Total: 13]

Question

Xerophytes grow in habitats with low rainfall and soils that often have high concentrations of salts. Fig. 4.1 shows the xerophyte Yucca treculeana growing on salt flats. Y. treculeana Fig. 4.1 (a) (i) Explain how xerophytes, such as Y. treculeana, are adapted to absorb sufficient water in the conditions in which they live. …… [4] (ii) Explain how xerophytes are adapted to reduce water loss to the atmosphere. …… [3] (iii) Xerophytes often have many defence mechanisms that reduce or prevent herbivores eating them. Suggest how xerophytes protect themselves against herbivores. …… [2] (b) Forest ecosystems can be affected by acid rain. Describe how the production of acid rain and its effects on forest ecosystems can be reduced. …… [4] [Total: 13]

Question

Bacteria are classified in the Prokaryote kingdom. (a) State two features of animal and plant cells that are not found in prokaryotes. 1 …… 2 …… [2] (b) Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacterium that is resistant to some antibiotics. Fig. 5.1 shows how a population of bacteria may develop antibiotic resistance and how the antibiotic resistance can be passed from one strain of bacterium to another. population of pathogenic bacteria A in patient 1 treatment with antibiotic Z started population of pathogenic bacteria A in patient 1 in the middle of treatment with antibiotic Z population of pathogenic bacteria A in patient 1 when treatment with antibiotic Z was stopped transmission of bacteria A to patient 2 bacteria A and B in patient 2 not to scale Key: bacterium of strain A bacterium of strain B resistant to antibiotic Z resistant to antibiotic Z bacterium of strain A bacterium of strain B not resistant to antibiotic Z not resistant to antibiotic Z dying bacterium of strain A plasmid Fig. 5.1 Explain how resistance to an antibiotic develops in a population of bacteria and spreads in the human population. …… [6] (c) Explain how the development of resistant bacteria, such as MRSA, can be minimised. …… [3] [Total: 11]

Question

In many parts of the world dairy cattle are kept in large barns and reared intensively, as shown in Fig. 6.1. Fig. 6.1 (a) Food for cattle that are reared intensively includes cereals, such as maize and barley. Ecologists have calculated that it is more energy efficient to grow crops for human consumption than for food for livestock. Explain why intensive rearing of livestock is not an efficient use of crops. …… [3] (b) The urine and faeces from cattle kept in barns is removed and treated in the same way as human sewage to avoid polluting the aquatic environment. Outline the effects of untreated waste from cattle on the aquatic environment. …… [4] (c) Intensive livestock production could be one way of preventing famine. Describe the causes of famine. …… [3] [Total: 10]