A man and a woman have a daughter and a son. Their dau6c m1i)*w *h 5cvajfceghter has normal vision, but theirw 6eafcj)* chi*vmc51 son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromou+.tyir-ws0j d+ jlt,somes of a somatic cell in a human male?

  There are two alleles for flower colour i,,zrpjlvmh *j2d36 1dkg d)brn snapdragons. However, the result of a cross between two hetel,j6 2z k)gd vh*prdr1j,bm3 drozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to th noc2plf42)n ke correct definition?

  Which of these statements is a correct definition for ab.+ji8)3evn; uent zv gene?

  The diagram shows a pari om :*n66j09tqmohwir of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were cross9x:qzuadtc ch +-m2t. ed in an experiment. Which row shows the expected phenotypic ra. 2d ucxmtc9t:z- qha+tios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a banded pafhdx;z67i(i;q-bl k l ttern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hf7xi; 6l ;z(hbdlqki-airs 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 in irp0c-xues4h v)p0+ qdividual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled suppsc4i0-v q r0+hxe)eeds.

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

  Neurons of the fruit fly (Drosop-6mp fsx ir-3c pluljb- 9*0vptfm 2p-hila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte 2l mcr3p0sxjl -*upm-f9 6-i fpbpvt-of a fruit fly?

  When does the random orientation of homologous chr7 ku f2nsk(;hnomosome pairs occur?

The majority of the genete9 vw di3y8 2u4q6k lut2o1ofs in the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below o u2olfv 1e823ttw k6i4uy9qd shows one representation of 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 oftns. x/vbh2 e( linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus)-qr1s asf(n 5wctg, tu8.qj 4r. Which arrow is pointing to a pair of auto1. t4cg sjr(,ur-nsaw8qtfq5 somes?

  Mendel observed that there are two possible variations of flower colour inte .*4m/l sedn pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1. What were the genotypes of the parentss4.*tdee nl/ m?

  The graph shows the frequency of birth weight of children born in London in 199dju d73 q fl iwncs.(hv:v2o;21.hju: dqw(iol2 sv3;f .dc vn27

  Which of these traits crp x0t0;q)1i3hpc5f ; a a1vz roh;wfis an example of continuous variation?

  Which row correctly describes diploid and haplovw4+h)gpj40zkqj4q o x;/b r+nb1gpeid cells in humans?

  The following table shows the diploid chromosome numwa:q,(2 gj ,v6mr rj sc00xiecber of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessh0mcq05 dm5 3js x;rqjive 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 t us3o5+hh 1pvjype A had a child with blood type O. What are the p3soup h1j5 h+vossible genotypes of the biological father?

  Which row shows the correct annot p4; k.e+n2bz(0z khi4ntbr hjation of the alleles for blood groups?

  Which of these statements are trvy ,ih8r.i6l60 oqikt ue 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 incidence of sickle cell a)b3)l bj6 w sde3bkx)anaemia and the spread of malaria across the continewj d))b bk)bs6e3l a3xnt 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 przew.ea9o,;; ij -.:hetpuwn zuyvalskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b)z.i y;9uwpnv;.:eht -jeu, o a 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 and unlinked ugggn4 tr 1i4 s;q2g(agenes.

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

Sickle cell anaemia is caused by+b46u f7/7 jb obpesdsk 25i8nc(cqdp the 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 betwee3upc0+- 9qz7 hyf2vx ty;ansdn a male cat that is homozygous for brown, long hair and a female cat that tyy +n0-fvau dh; zc79pxs23qhas black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum d6.df s:prizua 92d(d officinale), the allele for diamond-shaped seeds (D) is dominant over ovalfszid (dp ra u:9d2d.6-shaped seeds (d) and the allele for long seeds (L) 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 do:ji1gq *bg+m*+ pm2gqnnh+ bdminant 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 pigs and a chi-squared test (χ2) was carried out on the mgn*q:hg qdin1j* +gb+2m+bpoffspring.



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 shownq 3xft)w.n ezekzhhi:g (:i17dngl-iauy; // in the pedigree chart below?tq ykdf)e-3i i:az7:n hx /ge;/guih. (z ln1w

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

  Which of these statements about alp 97) b)ikckgenetic 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 polygenipwz o/y/+: 8bu m; *oqaj xzmeug(2*gyc traits 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 the p,gqrp 3iuk ,g1edigree chart is X-linqgk,1 u 3i,grpked recessive and not autosomal recessive?

  Different species of living organisms havepzv)kgm:e++n different numbers of genes characteristic to them. The table shows the estimated number of genes for five speci :)nvegkm++zp es.
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 flow1rft vi4srr842d0m 3 k3 hykyuer colour. If the pea plants Mendel was studying can only be white or pu14m vd30iu2s4yr tk8f3rhyk r rple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a 2df6 jz*n; x jr;n:h8b-u bsvdkt -8ebbiological female without hemophilia have a daughter without hemophilia. What are the possible genotypes j bnbev 6ds-8;*: zdb jfhxrnuk t;2-8of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus an.h09rtwd*(hq 1x w;pkrw9 gwfnuus) 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 7.82. The calculated value for the chi-squt d1gh w ;wxq9prwh9r. 0*f(wkared test was 10.05; what does this indicate?

1.Explain how parents with blood type A ajm.ub e( ( ib7b/nvbr*nd blood type B can have a child with blood tyb(bvjume*i7(rn /b b.pe O.

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

3.Explain the role of inheritance in genetic diseases.