A man and a woman have a daughter and a son. Their daughter has aw9 b,;g*q.v,i*;2sxpo cyjj ajtwh6 normal vision, but their son is colourbliihj,v6 *j gs. 2jxo;ww y;*a, 9tpcbqand. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows therdp 19xe99(wb tm/ty b sex chromosomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapd f w :/k-smxf-l2 )nbslzde:c*ragons. However, the result of a cross between two heterozygous plants yielded offspring with three differenb* lx-2:s)f-f:nl deksz c/wm t observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the corex qm dgd3j/m-25x0do rect definition?

  Which of these statements is a correct definition for a gener3ajq 4wt8icr d32k*pv +zl+a?

  The diagram shows a pair of ho3ngz9 2)4zg fqd ec(nlmologous chromosomes.

How many loci are shown?

  Two individuals, heteroz-z 8zw/onu++ jk7m ccl;fou 3yygous for a specific trait, were crossed in an experiment. Which row shows the expected +-c o j7u8flzu zm3ynko/w+c;phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes indizmc3mmygm48b j)),a/ire i 6ryx lq6;vidual hairs to have a banded pattern. The non-agouti allele causes hairs to be a si8mami yrg/ mb 6 )xyilerz46) c;q,3mjngle colour. Individuals who are heterozygous have hairs with a banded pattern.

Which combination of parent genotypes would allow for production of offspring that do not have the agouti characteristic?

  Mendel observed that the seed shape in individual pea plants was either rou2w+ d iyxe;r;tnd or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring wit dw;i;2etry +xh wrinkled seeds.

Which row in the table below states the most likely genotypes of the parents?

  Neurons of the fruit flaku x)7 c6ab;fa/9u3z* ns meuy (Drosophila melanogaster) have 8 chromosomes. How many chromosoaku)x ;e9/a6 n acm3us7f* zbumes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of ho)d qp avtpr4jr. (2rq1mologous chromosome pairs occur?

The majority of the genes in the human genome have already been mxb nb(k q 6j0qs.juk(i)fql:- apped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation offku- .j6q((skqinjl :bx) qb0 a homologous pair of chromosomes.

1.Define locus.

2.Identify the number of loci shown in the diagram.

3.Distinguish between gene, allele, and locus.

  Which is the correct definition b hq4/7gsrtj :0o:-.6tlq:yoz ysmqtof linked genes?

  The diagram shows a karahxu/hc.mx +- /bu, vk bau,u0yogram of a brown male rat (Rattus norvegicus). Which arr bv0- ,uk,ab/uhhau mc/xx+u.ow is pointing to a pair of autosomes?

  Mendel observed that there are two possible variations of flower colour in pea pr; yt6m qasv -koi*)tx(+dq (ulants, purple and white. After a genv(ia ;s)+qx-6ty uo(d*tr k mqetic cross, the ratio of plants with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birtj;2xmivth*d- h weight of children born in London in 1991. *d;xt i2j-v hm

  Which of these traits is an examn ea jqabp5pj/.p07s. ple of continuous variation?

  Which row correctly describes diploid and haploid cells in humans? r xfh p 0*97rod*zrtf9

  The following table shows jz3id5xl+ 7na wff brj*wa(+ )the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive 7.+2 xvpdlhw* ouiqn8 allele (Hb$^S$). The dominant allele is Hb$^A$. This image shows the inheritance of sickle cell anaemia in a family.

What are the genotypes for individuals 1 and 7?

  A biological female with blood type A had a child with blood type O. What are:5beh57nr)y qj7kn gk the possible genotypes of the biological fatherkb 7h 5gjy nqr7:)e5nk?

  Which row shows the correct annotcjf.;xx fuk(. 8jq+i6zus.xb d o/+aa ation of the alleles for blood groups?

  Which of these statements are tru2kmg5ltv/dwvgd37fl p;)qh-3 iy r y0e for alleles?
I. Alleles are versions of a gene
II. Alleles differ by one or more base
III. Alleles affect the same characteristic

The maps show the incvzf0a2yt l0: bh.z mj-idence of sickle cell anaemia and the spread of malaria across the contzzajy2-.m0l t 0vf:b hinent of Africa.


The graph shows the average density of malarial parasites present in the blood of Hb AA (not affected by sickle cell anaemia) and Hb AS (carriers of sickle cell anaemia) people in Sub-Saharan Africa.

1.Compare and contrast between the distribution of sickle cell trait and malaria in Africa.

2.1.State the mode of inheritance of sickle cell anaemia.

2.2.Using a genetic diagram, determine the probability of a child having sickle cell anaemia, if both their parents are carriers of the disease.

3.Blood samples were taken from children to create the graph. Suggest one difference between the appearance of blood cells in Hb AA and Hb AS samples.

4.State at which age there is the largest difference between the number of parasites found in the blood of Hb AA and Hb AS samples.

5.Suggest one difficulty of collecting sufficient data for this study.

6.Using your own knowledge and the data provided, discuss whether carrying the sickle cell allele offers protection from malaria.

In Mongolian horses (Equus przewalskii), fur colou7:/ihb/3lchc wj tf1z r is determined by a number of genes. Brown colour (B) is dominant to sandy col/7lw z/hfh3bic j :c1tour (b) and an ombre (two tone) colour (P) is dominant to one tone (p).


1.A homozygous sandy ombre male horse is crossed with a heterozygous horse for both traits. Draw a Punnett square to show the potential results of this cross.

2.Identify the possible genotype recombinations, after fertilisation, from the cross in part (a).

3.In pigs, the curly tail is dominant to the straight tail, and pink skin is dominant to black skin. On a pig farm, the resulting phenotypes from double-heteroygous genotype breeding were recorded. The chi-square value for the phenotypes of the offspring was calculated and the result was 340.6.
The table below shows the degrees of freedom (D.f.) and critical values at a significance level (p) of 0.05 (5%) for a chi-squared test.
Discuss whether the genes for skin colour and tail shape in pigs are linked or unlinked.

1.Distinguish between linked+c* wtgv ,u0afbmqp 27 and unlinked genes.

2.Coat colour is a polygenic trait. State the meaning of polygenic.

Sickle cell anaemia is caused by :nj+y 1n ;ufujthe allele Hb$^S$ . The normal allele is Hb$^A^ .

1.Identify the genotype of individuals 1 and 2.

2.Predict the probability of individuals 5 and 6 having another child that is unaffected. Justify your answer.

3.If individual 7 had a child with an affected biolgical female, identify the possible genotypes of the child. Justify your answer.

4.Deduce, with evidence, the pattern of inheritance of sickle cell anaemia that is shown in this pedigree chart.

5.Distinguish between sex-linked inheritance and autosomal inheritance in humans.

  The diagram below shows a cross between a male cat that is homozygous for pro 7rwp09pr7brown, long hair and a fr0p9 p7o rw7rpemale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for dih+pvl;n 3gpj+amond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L)n;h g 3jl+p+vp is dominant over short seeds (l).

In a genetic cross between a dandelion that is heterozygous for both traits and a dandelion that is homozygous recessive for both traits, what would be the expected proportion of long seeds?

In guinea pigs (Cavia porcellus), long hair (L) is dosuqun ,2,nh 9zminant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous lz2 unus9, ,qhnong, curly-haired guinea pigs and female short, straight-haired guinea pigs and a chi-squared test (χ2) was carried out on the offspring.



1.1.Using a genetic diagram, state the expected ratio of the cross between the two parents.

1.2.Identify the recombinants.

2.1.Calculate the ratio of the observed phenotypes.

2.2.Suggest a reason for the difference between the expected and observed ratios.

3.1.State the null hypothesis in this study.

3.2.Deduce with reasons whether the null hypothesis should be accepted.

  What best describes the inheriyl mhb;kr9-543ol h vdtance of the condition shown in the pedigree chart belo hbv-l5 doymh3l49;krw?

I. Sex-linked trait
II. Dominant trait
III. Recessive trait

  Which of these statements about genetic disorders is/are correct? 6t2z ii6k)tpg9lk/ yj

I. The majority of genetic disorders are caused by recessive alleles.
II. Genetic disorders can be sex-linked.
III. Offspring of two parents with the same genetic disease will always be affected.

1.Outline how polygenic traiax t*j4llq :a0q*x ,kfn-u6g xts can show a normal distribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  What suggests that the inheritance of the disorder shown in them cc.m/6df:v y xgz4syo41mq8;2basb pedigree chart is X-linked recessive and not autosbq1m.dxbgc c z m/s4maf yo;s vy4:682omal recessive?

  Different species of living organisms have difh-+hiw k2hx r-ferent numbers of genes characteristic to them.w +xkh 2h-hir- The table shows the estimated number of genes for five species.
Species Estimated number of genes
Escherichia coli (bacteria species) 4,000
Drosophila melanogaster (fruit fly) 13,000
Canis lupis familiaris (dog) 20,000
Homo sapiens (humans) 30,000
Oryza sativa (rice) 40,000
1.Using the information in the table deduce the estimated number of loci in a human genome.
Estimated number of loci in a human is   .
2.Explain how a mutation can affect a characteristic.

  Mendel studied eight characteristics of pea plants, includ(2 k7z3esqhlting flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of thesetzs 73q(khl2 e statements was correct?

  A biological male with hemophilia and a biological female without hemophilia h 9ht * 9vc9sw ;oq0+ vxpjiyjsqjy(5(iave a daughter without hemophilia. What arpwtj90c9x;s ( qyj*sq+(yvoij9hvi5 e the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunf)r , pm/3xay 2m1lwnly h2qr9klower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical value for the chi-squared test at the 0.05 significance level was 7.82p )mk,q ny1 22l3har9rw/x lmy. The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A and bloodk1x3arz ,f8 1xey av2k type B can have a child with blood t rxavak3f2xk 1, 18eyzype O.

2.Outline how polygenic traits can show a normal distribution.

3.Explain the role of inheritance in genetic diseases.