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QUESTION 2 Which form of inheritance usually determines traits that display continuous phenotypic variation? (A) polygenic (B) sex-linked (C) multiple allele (D) incomplete dominance
QUESTION 15 In watermelon skin colour is controlled by a single autosomal gene. The two phenotypic variants are green and striped. Two plants one homozygous for the green alleles and one homozygous for the striped alleles were crossed. The figure shows the phenotypic frequency for the initial (F ) generation and the subsequent (F ) generation. Frequency 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Key I:’ green striped Fy F| Generation A cross was then performed between members of the F| generation. What would be the expected frequency of striped watermelon in the next (F ) generation? A) 1.0 (B) 075 (C) 0.50 (D) 0.25
QUESTION 4 To demonstrate polygenic inheritance of colour in wheat a cross was performed between two intermediate parents (AaBbCc X AaBbCc). Each dominant allele adds a “unit’ of colour to the phenotype. Which graph would depict the number of individuals and number of phenotypes for the cross? A 2 B) =z = 3 2 2 3 3 g g G~ G~ S o 3 z 2 2 Z Z 1 2 3 4 5 6 7 1 2 3 4 5 6 Number of phenotypes for colour Number of phenotypes for colour © = D) = - 5 = 2 3 3 g g = G~ S S 3 3 E g S = Z Z 1 2 3 1 2 Number of phenotypes for colour Number of phenotypes for colour
QUESTION 6 The pedigree traces a genetic disease across two generations. Generation [ Key Carrier (not affected) Affected Normal Female O ' Q Generation II Male [l . D The inheritance pattern of this disease can be classified as (A) 1incomplete dominant. (B) autosomal dominant. (C) sex linked. (D) polygenic.
QUESTION 25 (3 marks) In blood group inheritance in humans three alleles (i I** and I®) determine blood type which can be type O A B or AB. It is known that: o allele I* produces type A and is co-dominant with allele 1B which produces type B « allele 1 produces type O « alleles I* and I® are dominant over allele i. A father who i1s heterozygous type A and a mother who is heterozygous type B have children. Predict the likely frequency of phenotypes for their offspring. Show your working.
QUESTION 9 Polygenic inheritance involves multiple (A) alleles for a single gene. (B) genes with the same alleles. (C) genes coding for a single characteristic. (D) characteristics resulting from a single gene.
QUESTION 10 (3 marks) In fruit flies eye colour is a sex-linked trait inherited on the X chromosome. The red-eye allele (R) is dominant over the white-eye allele (r). A red-eyed male and white-eyed female have 50 offspring. Use a Punnett square to predict the number of male and female offspring and their eye colour.
QUESTION 19 Polygenic inheritance is defined as (A) one characteristic controlled by one gene. (B) one characteristic controlled by multiple genes. (C) multiple characteristics controlled by one gene. (D) multiple characteristics controlled by multiple genes.
QUESTION 28 (5 marks) The figure below shows a model of ecological niche occupation by species A—E. : T :_¢§ Species D - ‘© 2 | ® % © . m = 2 Z 2 3 Cool Warm Niche axis 2 — Temperature a) Identify which two species are occupying the same ecological niche. [1 mark] b) Species A and B have a common ancestor. Which diversification pattern would have occurred between species A and species B for them to occupy these niches? [1 mark] The table below shows the frequencies of genotypes and phenotypes for a particular trait in a generation of species E. Genotype (% frequency) Phenotype (% frequency) TT (0) Tt (100) tt (0) Phenotype 2 (0) c) Predict the next generation’s genotype and phenotype frequency. Which type of inheritance pattern is represented for Phenotype 17 Phenotype 1 (100) [3 marks]
QUESTION 3 (7 marks) The chart shows the inheritance pattern of a trait which is thought to be sex-linked dominant. Key C] Male with the trait Parents @ Female with the trait Offspring |_] Male without the trait 1-16 used to identify each individual ©) Female without the trait a) Identify how many offspring of individuals 1 and 2 have the trait. [1 mark] b) Identify evidence to support the conclusion that the trait is sex-linked dominant. Justify your response using a Punnett square. [4 marks] c) Infer the genotype of individual 6. Explain your reasoning. [2 marks]
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