Quelpr
1 markPatterns of Inheritance

CAPE Biology Unit 1 · 2017 · Paper 2 · Question 2(b)(i)

A geneticist crossed two types of pea, obtaining 5474 plants with round seeds and 1850 plants with wrinkled seeds in the F₂ generation. You need to use the Chi-square test to determine if these results are consistent with the 3:1 ratio expected from a monohybrid cross.

State the null hypothesis for this test.

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 2(a)(i)State the genotypes of the following: A normal clotting male; A normal clotting carrier female.[2 marks]
  2. 2(a)(ii)Using the genotypes stated in (i) as parental genotypes, construct a Punnett square diagram to show how haemophilia-affected offspring can result from normal…[3 marks]
  3. 2(a)(iii)Give an explanation as to why a man with haemophilia cannot pass on the condition to his son.[1 mark]
  4. 2(b)(ii)Calculate Chi-square using the formula, Chi-square = Σ(Ο - E)²/E, where O is the observed and E the expected number of plants. Show your working in tabular…[2 marks]
  5. 2(b)(iii)Use the data in Table 2 on page 10 to make an inference based on your calculated Chi-square value.[2 marks]
  6. 2(c)(i)Using the axes provided in Figure 3, illustrate the effect of disruptive selection on the population distribution in Figure 2.[1 mark]
  7. 2(c)(ii)Using Darwin's theory of natural selection, explain how disruptive selection can lead to the formation of new species.[3 marks]

More practice: the rest of this paper · more Patterns of Inheritance questions · all CAPE Biology Unit 1 past papers