Quelpr
1 markPatterns of Inheritance

CAPE Biology Unit 1 · 2008 · Paper 2 · Question 2(a)(i)

Flower colour in certain plants is controlled by two genes. One gene codes for colour pigments in the petals, with alleles R (red) and r (white) being co-dominant. The other gene codes for an enzyme system that enables pigment production, with alleles C for active enzymes and c for inhibited enzymes. Homozygous recessive plants (cc) cannot synthesize pigment and produce white flowers. A plant with genotype RRCC is crossed with a double homozygous recessive plant.

State the genotype of the F1 plant.

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 2(a)(ii)State the phenotype of the F1 plant.[1 mark]
  2. 2(b)State the FOUR different combinations of the alleles carried in the gametes of this F1 dihybrid plant (plant produced in (a) above).[1 mark]
  3. 2(c)(i)Use the Punnett Square shown in Table 1 to show the genotypes of the F2 generation of this dihybrid cross.[2 marks]
  4. 2(c)(ii)Give the ratio of red : pink : white flowers.[3 marks]
  5. 2(d)Complete the Chi-squared calculation in Table 2 and the final Chi-squared sum using the formula provided.[4 marks]
  6. 2(e)(i)How did the students determine the degrees of freedom?[1 mark]
  7. 2(e)(ii)The students checked the 5% probability in order to determine whether the result was significant or insignificant. What was their decision, and why?[2 marks]
  8. 2(e)(iii)If the Chi-squared value had been 7.0, what information could have been gained concerning the results of the monohybrid cross experiment?[1 mark]

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