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4 marksPatterns of Inheritance

CAPE Biology Unit 1 · May/June 2024 · Paper 2 · Question 2(a)(ii)

A test cross in tomato plants involving fruit shape (ox-heart or plum) and fruit size (cherry or beefsteak) with dihybrid genotype OoBb crossed to a pure-bred plant yielding plum, cherry fruit produced 620 offspring with phenotypes: Oxheart, beefsteak (160); Oxheart, cherry (155); Plum, beefsteak (165); Plum, cherry (140).

Complete the shaded boxes in Table 1 to determine the value of chi-squared (χ²), to two decimal places.

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Other parts of this question

  1. 2(a)(i)State the expected offspring phenotype ratio of the test cross.[2 marks]
  2. 2(a)(iii)Outline a suitable conclusion based on the results obtained in (a)(ii), if the critical chi-squared value for three degrees of freedom at p = 0.05 is 7.82.[2 marks]
  3. 2(b)(i)State TWO features of restriction enzymes.[2 marks]
  4. 2(b)(ii)List THREE advantages associated with the use of genetically modified organisms.[3 marks]
  5. 2(b)(iii)List THREE disadvantages associated with the use of genetically modified organisms.[3 marks]
  6. 2(b)(iv)On the grid provided on page 15, plot the data shown in Table 2 as a line graph and draw a curve of best fit.[5 marks]
  7. 2(c)Explain if EACH of the methods shown in Figure 4 can produce DNA that the bacterium E. coli can use to make amylase on a large scale. Present your response in…[9 marks]

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