page 14 5. The diagram shows some features of a plasmid which has been cut open by a restriction endonuclease to allow a gene from a donor chromosome to be inserted. The DNA recognition sites for three restriction endonucleases, E coR1, BamH1, and HindIII, are shown in the table. The arrows indicate where each restriction endonuclease cuts the DNA sequence. ampicillin resistance gene region X G C T T A A C T T A A G Restriction endonuclease DNA sequence recognised BamH1 E coR1 HindIII G G A T C C C C T A G G G A A T T C C T T A A G A A G C T T T T C G A A DO NOT WRITE IN THIS MARGIN page 15 MARKS DO NOT WRITE IN THIS MARGIN 5. (continued) (a) (i) A restriction endonuclease was used to remove a gene from a donor chromosome. Use information from the diagram and the table to identify the restriction endonuclease which would be used to allow the gene to be inserted into the plasmid. Give a reason for your answer. Restriction endonuclease Reason (ii) Name the enzyme which would be used to seal the gene into the plasmid. (iii) A culture of bacterial cells, 20% of which had taken up this modified plasmid, were grown on a nutrient agar plate. The plate was incubated and 250 colonies of this bacteria grew. Predict the number of colonies which would have been expected to grow if the nutrient agar plate had contained the antibiotic ampicillin. Space for calculation (b) Name region X, shown in the diagram, which ensured that the modified plasmid would be passed on to daughter cells. [Turn over 2 1 1 1 page 16 MARKS DO NOT WRITE IN THIS MARGIN 6. An investigation was carried out to monitor the populations of red squirrels (Sciurus vulgaris) and grey squirrels (Sciurus carolinensis) in a 15 km2 wooded area. The average number of breeding pairs of each species was recorded between September 2010 and June 2012. The results are shown in the graph. (a) (i) Use values from the graph to describe the changes in the average number of breeding pairs of grey squirrels from March 2011 to March 2012. (ii) Calculate the total number of breeding pairs of red squirrels in the wooded area in September 2011. Space for calculation breeding pairs (iii) Express, as the simplest whole number ratio, the number of grey squirrels to red squirrels in June 2012. Space for calculation 2 1 1 grey red : Sep 2010 Dec 2010 Mar 2011 Jun 2011 Sep 2011 Dec 2011 Mar 2012 Jun 2012 3·0 2·5 2·0 1·5 1·0 0·5 0·0 Month and Year Average number of breeding pairs of squirrels/km2 Red Squirrel Grey Squirrel Key page 17 MARKS DO NOT WRITE IN THIS MARGIN 6. (continued) (b) Pine martens (Martes martes) live in wooded areas and prey on squirrels. Populations of pine martens, red squirrels and grey squirrels were estimated in two other wooded areas using automatic cameras. These cameras are triggered by the movement of passing animals. The results are shown in the table. Wooded area Estimated number of grey squirrels Estimated number of red squirrels Estimated number of pine martens 1 88 645 45 2 465 112 12 (i) Suggest why the method used to estimate the numbers of pine martens and squirrels may lead to inaccurate results. (ii) Use evidence from the table which could be used to support the following statements. 1 Pine martens are more successful predators of grey squirrels than of red squirrels. 2 Grey squirrels compete more successfully for food than red squirrels. (c) Grey squirrels have spread rapidly and eliminated native red squirrels from much of the UK. State the term used to describe grey squirrels in the UK as a result of this. [Turn over 1 1 1 1 page 18 MARKS DO NOT WRITE IN THIS MARGIN 7. Oil extracted from the seeds of the crop false flax (Camelina sativa) can be used as fuel. An investigation was carried out into the effect of a plant growth regulator paclobutrazol (PBZ) on the photosynthetic pigment content of the leaves and the oil yield from the seeds of false flax. The results are shown in the table. Treatment Average photosynthetic pigment content (mg/g of leaf) Average oil yield (g/plant) Chlorophyll a and b Carotenoids Untreated 3·28 3·02 1·7 Treated with PBZ 3·27 3·98 2·4 Absorption spectra for pigments from the treated and untreated plants were produced and are shown in the graph. (a) (i) Use values from the graph to describe the difference in absorption spectra of the pigments from treated and untreated plants. 1 Wavelength of light (nm) Increasing absorption of light 350 450 550 650 400 500 600 700 pigments from treated plants pigments from untreated plants Key page 19 MARKS DO NOT WRITE IN THIS MARGIN 7. (a) (continued) (ii) Use evidence from the table to explain the difference in the absorption spectra. (iii) State one use that plants make of the light energy absorbed by pigments during photosynthesis. (b) Suggest why seeds from the plants treated with PBZ yield more oil. [Turn over 1 1 2 page 20 MARKS DO NOT WRITE IN THIS MARGIN 8. Salmon can be reared in fish farms where they are sometimes fed small fish such as anchovies. Anchovies feed on animal plankton which feed on plant plankton. The energy contents at each trophic level in this food chain are shown on a log scale in the bar graph. (a) (i) State the energy content fixed in the biomass of salmon. kJ (ii) Plant plankton fix 2% of the solar energy they receive in their biomass. Calculate the total solar energy to which the plant plankton were exposed. Space for calculation kJ 1 1 100,000 10,000 1,000 100 10 1 Plant plankton Animal plankton Anchovies Salmon Organism Energy content fixed in biomass (kJ) page 21 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (b) The human population is increasing. (i) State the term used to define the ability of the human population to access food of sufficient quantity. (ii) In terms of energy explain the advantage to the human population of consuming anchovies rather than salmon. [Turn over 1 1 page 22 MARKS DO NOT WRITE IN THIS MARGIN 9. The diagram shows crosses in a breeding programme involving different breeds of sheep. (F2) Commercial lambs Greyface female (F1)  X  Suffolk male (P) Scottish Blackface female  X  Border Leicester male (a) Suggest a reason why breeding programmes such as this include crossbreeding. (b) Explain why Greyface sheep are produced by crossbreeding Scottish Blackfaces with Border Leicesters instead of breeding F1 Greyface sheep together. (c) To produce commercial lambs which show a desired dominant characteristic, Suffolk males homozygous for that characteristic are used. (i) Name the type of cross used to identify if the genotype of the desired characteristic in Suffolk males is homozygous. (ii) Explain the importance of selecting a Suffolk male homozygous for the desired dominant characteristic. 1 1 1 1 page 23 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (d) Spider lamb syndrome is a hereditary condition in sheep caused by a recessive deleterious allele which results in limb deformities. State why inbreeding could cause an increase in the number of lambs born with this condition. [Turn over 1 page 24 MARKS DO NOT WRITE IN THIS MARGIN 10. An experiment was carried out to investigate the evolutionary relatedness of four species of fish by comparing proteins extracted from the fish. The more closely related species are, the more proteins they have in common. A sample of muscle tissue from each species of fish was heated in a solution to extract proteins. The protein extracts were analysed by gel electrophoresis which separates proteins according to their mass. A protein standard containing proteins of known masses was also analysed. The results of the gel electrophoresis are shown in the diagram. Each band represents a protein. Mass of protein in protein standard (kDa) Distance travelled (mm) 16 50 20 38 26 30 44 24 66 15 108 10 (a) (i) Identify two variables related to the protein extraction, not already mentioned, which should be kept constant so that a valid conclusion can be drawn. 1 2 (ii) During the preparation the samples were heated. This unfolds the proteins changing their three-dimensional shape. Name one type of bond that could have been broken to cause this change. 2 1 Protein band X Direction of movement of proteins Protein standard Species 1 Species 2 Species 3 Species 4 page 25 MARKS DO NOT WRITE IN THIS MARGIN 10. (continued) (b) (i) Draw a line graph to show the distance travelled by the protein bands in the gel against the mass of protein in the protein standard. (Additional graph paper, if required, can be found on page 33) Mass of protein in protein standard (kDa) (ii) Band X travelled 28 mm. Use the graph to identify the mass of the protein in band X. kDa (iii) Each species of fish contains a protein with a mass of 66 kDa. One amino acid has an average mass of 0·12 kDa. Calculate how many amino acids that would be expected in this protein. Space for calculation (iv) Explain why it was concluded that species 1, 2 and 4 are more closely related to each other than they are to species 3. 2 1 1 1 [Turn over page 26 MARKS DO NOT WRITE IN THIS MARGIN 11. Answer either A or B. A Write notes on components of biodiversity and how these are measured. OR B Write notes on parasitic relationships and transmission of parasites. 4 4 page 27 MARKS DO NOT WRITE IN THIS MARGIN 12. Congenital lactase deficiency in humans is caused by very low activity of the enzyme lactase, resulting in individuals being unable to digest lactose in milk. This is caused by a number of different mutations in the lactase gene. (a) One of the mutations involved causes a frame-shift mutation in the lactase gene. (i) Name a gene mutation which causes a frame-shift. (ii) Describe the effect of this frame-shift mutation on the lactase gene and on the structure of lactase. Effect on lactase gene Effect on structure of lactase (b) (i) Some mutations occur in the sequences which regulate the transcription of the lactase gene. Suggest why this may lead to more lactase enzyme being produced. (ii) Mutations in this gene are more common in Finland than in other parts of Europe. This is thought to be due to a small number of individuals who settled in Finland many generations ago. State the term which describes this change in gene frequency when a small population of individuals breaks away from a larger population. [Turn over 1 2 1 1 page 28 MARKS DO NOT WRITE IN THIS MARGIN 13. Scientists have used chemicals to produce polyploids to try to improve the characteristics of kiwi fruit plants. The table shows some characteristics of fruit from the original diploid plant (2n) and two polyploids produced from it (4n and 6n). Characteristics of fruit Ploidy Average fruit mass (g) Average fruit length (mm) Average fruit diameter (mm) Vitamin C content (units) 2n 96·5 74·4 51·7 123·0 4n 115·8 76·1 60·0 119·0 6n 145·0 86·8 60·0 124·0 (a) (i) State which characteristic is least affected by polyploidy. (ii) Describe the relationship between ploidy and average fruit diameter. (b) Calculate the percentage increase in average fruit mass when the chromosome number is doubled. Space for calculation % 1 2 1 page 29 MARKS DO NOT WRITE IN THIS MARGIN 13. (continued) (c) Describe the event that has occurred in the cells of the kiwi fruit plant that resulted in polyploidy. (d) Polyploids have whole genome duplications. Explain the importance of this in evolution. [Turn over 1 1 page 30 MARKS DO NOT WRITE IN THIS MARGIN 14. Answer either A or B in the space below and on pages 31 and 32. A Write notes on DNA under the following headings. (i) Organisation of DNA in prokaryotic and eukaryotic cells; (ii) The polymerase chain reaction (PCR). OR B Write notes on RNA under the following headings. (i) Structure and functions of different types of RNA; (ii) RNA splicing. 4 5 6 3 page 31 MARKS DO NOT WRITE IN THIS MARGIN SPACE FOR ANSWERS page 32 MARKS DO NOT WRITE IN THIS MARGIN SPACE FOR ANSWERS [END OF QUESTION PAPER] page 33 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Additional graph paper for question 10 (b) (i) Mass of protein in protein standard (kDa) page 34 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 35 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 36 [BLANK PAGE] DO NOT WRITE ON THIS PAGE