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Pearson Edexcel IAL Biology 2.15 Inheritance terminology & monohybrid inheritance

Practise using inheritance terms, pedigrees and genetic diagrams to predict genotypes, phenotypes and monohybrid probabilities.

Syllabus
First assessment 2019
Course
Biology YBI11
Level
AS

Exam points

  • interpret pedigrees and tables to identify genotype, phenotype and carrier status
  • draw monohybrid genetic diagrams showing parental gametes and offspring outcomes
  • calculate inheritance probabilities for dominant, recessive or X-linked traits

2.15—Inheritance terminology and monohybrid inheritance question 1

[Maximum number: 4]

Most Bengal tigers are orange with black stripes but there is a very small number of Bengal tigers that are white with black stripes.

The photograph shows a white Bengal tiger with black stripes.

Figure for Question 2.15—Inheritance terminology and monohybrid inheritance question 1 — Edexcel A-Level Biology AS

White tiger offspring are produced by two Bengal tigers that each carry at least one recessive allele for a gene affecting coat colour.

The pedigree diagram shows the phenotypes in one family of tigers, bred in captivity.

Figure for Question 2.15—Inheritance terminology and monohybrid inheritance question 1 — Edexcel A-Level Biology AS

Key female orange tiger female white tiger male orange tiger male white tiger

Question (a)

(a)

The phenotype is affected by the genotype.

State what is meant by the term genotype.

[ 1 ]

Question (b)

(b)

Determine the expected phenotypic ratio of orange tigers to white tigers born to the parents shown in this pedigree diagram.

Use a genetic diagram to support your answer.

Answer

[ 3 ]
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