A man and a woman have a daughsu8hk +vz 8e6)kdtxii/mx y5)ter and a son. Their daughter has normal vision, but their son is colourblind. Which one of these xhud iiyk8) m)5/tz6+8 k vxesgenotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell infbp)2gy*5: dyema +a; q;fzth a human male?

  There are two alleles for flower colouf:oxxw : t)0srr in snapdragons. However, the result of a cross between two heterozygous plants yielded offsprfxtow s0:):xr ing with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is mat vzagi1lf) s3,ched to the correct definition?

  Which of these statementsw(a a1yigoduon* z8unv6..a-4 mb *jd is a correct definition for a gene?

  The diagram shows a pair ofhp7r 9(snf vi4 homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a spect oqaj3r lvi4g :t38-mific trait, were crossed in an experiment. Wrt8itv q l:m ga4oj3-3hich row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to k g*qv1y4wfn 0have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals*fyk1vwqn0 4 g 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 wasx0,aiqe(*h 4r ozi:zs either round or wrinkled. The results of an experimezhxzra(4q : seoi0i, *ntal cross yielded 315 offspring with round seeds and 105 offspring with wrinkled seeds.

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

  Neurons of the fruit fly (Drosophila melanogp9l w)atp8i56xt4t-b5 hoi s gaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fruit fl hilp9)6-t 54 aixb8towtg5s py?

  When does the random orientation o8nod ;-m7xe (smixk 0af homologous chromosome pairs occur?

The majority of the e p- n(jqz6 8:dd*orcr-v8jxm 6)axvfgenes in the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pai fmn6jjdvra-z: -eo q8xcpx(v d)68*rr 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 defi0xrby y(6o qi(nition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Which ar gsxq)*ck /h+crow is pointing to a pair of auto)hs/kc c+qxg*somes?

  Mendel observed that there are two possibss3:. n v, oj+l3-a 2jp0 oo:endjvlmkle variations of flower colour in pea plants, purple and white.,.som 0jo lk pvsl3j::-n2+ona3jve d After a genetic 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 birth weight of childrenbih r +u42)x.9vufoueixm (.x born in London in 1991.x e(+oim24uhxrix u .b.ufv9 )

  Which of these traits is an example of conbf./j.t2o8q d( ynquh tinuous variation?

  Which row correctly descritda 5c2 .88sas6pdiyqbes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species. vnr*z2 8m9trdcz 4b0 y

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allela7y-6 1uhw smgx 5:;nkmii /yce (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 cejqnk h/re5xu;dkjvup0 u iul0)* 7*;hild with blood type O. What are the possible genounkvel; 5j*dq; xe*kh)uu70jupi /0rtypes of the biological father?

  Which row shows the correct annotation of the alleles for blood grou wo8q;(/euk/oubo0c/ g ithqq o-h(8qps?

  Which of these statements are true for alle9+,qz du)nl dn5ifuy0t j wl2m6-st7l les?
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 incidence of sickle cell anaemia and the spreaantek4 iz(of d,x,03od of malaria across the continent o,tk4o o3df0e,(xz anif 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 colour is determined by: ft ww:q335swsjnh 0b a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to one tone (p).0ntq sjw3bww35 : fsh:


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 and unlinkxf 4:b8lw -fzred genes.

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

Sickle cell anaemia is caused by the8t(794r j *n -otqoqtonw hnv) 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 homotwzcww ;c *x0*n-x6pwzygous for brown, long hw;*0t w w*-6 xcnxwczpair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacrw2* vz8f 2xyen+x0x oum officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short seeds (ly2 xez0f+ovwnrxx *28).

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 porcelh 3obuejad2t 10fu b.i+5uz2qlus), long hair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous long, curly-haired guinea pigs and female short, straight-haired guinea pi 0ubuj. uaozt1f+532eb2 dqi hgs 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 inheritance of the condition shown in the pedigree cha*rs1zd iv .x7 nr:p2clrtz7p vs .rr:lnc1 i*dx2 below?

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

  Which of these statements a4akl +o2,y h0oooc*)3pmnnmi1 ce g6ebout genetic disorders is/are correct?

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 traits ca4a vkd. ,vml9*yv(j j w/b4zaqn 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 t79jzz azo+ i7vhe inheritance of the disorder shown in the pedigree chart is Xz9 z7ja7o iv+z-linked recessive and not autosomal recessive?

  Different species of living organisms have different numo :qt*y9qbn hm99j0kj bers of genes characteristic to them. The table shows the estimated 9 bqn*9o:h9ym0kj tqj 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, including flowerya+o0pp gz 5)z qm2b/m colour. If the pea plants Mendel was studying can only bz m/)0+bqgyp 5om2apz e white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological fema5u9dnp4y jj +ido o+*0yu 2alyle without hemophilia have a daughter without hemophili+io4joly+ u9 20a y*ynd5u jpda. What are the possible genotypes of the daughter?

  A dihybrid cross was carrieelzf7btd0q;dz *8xv -d out between two sunflower 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 f; -8vd0zzbxd *7teq l7.82. The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parentswsgo0 ,+x: v8f9canss with blood type A and blood type B can have a child with blood+cswvaxgns: fs8o ,0 9 type O.

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

3.Explain the role of inheritance in genetic diseases.