A man and a woman have a daughter and a son. Their daughter has normal vistpd2s *:h qyn+ion, but their son is colourblind. Which one of these genotypes c :np*y+d2q hstould be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human malei/ajdfq(4 *)g qav:f e?

  There are two alleles for flower co0 t /ur6iv8fejlour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers.08eu iv6r ftj/ Which is the most likely explanation for this observation?

  Which keyword is matched to the correct definition9bz6diera2y lm0sdk)i(9 8 ol?

  Which of these statements is a correct definition for a:i1c(in 1ifxo( yt9lwo (e vd) gene?

  The diagram shows a pair of homologo/6 na4)jgxy( dk+ brnpus chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specg8)i+c 0:w 7/pm grmcuxbap3fific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting from thf/ugip8)g:rcm0w p + b3m7 xcais cross?

  In some animals, the q.tz.(olukwqg3 ffpr6 ,+*d 3 t-vkneagouti allele causes individual hairs to have a banded pattern. The non-agouti allele causes h gn3ftdp. kz6l+tu3.*qq rvk, e-w(foairs to be a single 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 eitherxnrp1b+a(n y3l()o.x tf3z ljak f;+ v round or wrinkled. The resultatjk;l+zbv( +3x x. 3fr(a n1of)y lpns of an experimental 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 melanogaster)5 t qk6hxslz/9ik0u r: have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a iuhl 95 0zk6q/rs:xtk fruit fly?

  When does the random orientation of homologous chc 74oq((y rmyhromosome pairs occur?

The majority of the genes in the human genome have a3o 0x))mt irnklready been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows onero)3m)0n kxti 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 of link29s mn(drg/cd / qyyl*ed genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Whwy/rba vuv mw*f9m( 9j1s:s( vi s,af6ich arrow is pointing to a pairjb /s9(m ,ws:9i 1*vwua(6 mrasffyv v of autosomes?

  Mendel observed that there are two possible variations of fll-m )ew (bol6xt*gga0swg 9 gr5j;oa(ower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to wh(( gar9m goso 5t*-w0ga egll)6 bwx;jite flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequenchpwvu tbcp()79/2ek xwo3uo ( y of birth weight of children born in London in 1991.p( uktceuo(b)7x9 w/pwv2 ho3

  Which of these traits is an example of continuous valoq) qkkq+la+0,ke o10hoi6oriation?

  Which row correctly d3n:a8 ,ypeyd310r kyrr q )zymescribes diploid and haploid cells in humans?

  The following table shoh5t7xlxy pgk q6 il-,8psv3 k.ws the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive hqhy9wn.6 2bmallele (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 wizeqf4pru7 2/g*vcgp lj os 0ksu2(+y+ th blood type A had a child with blood type O. What are the p7uy2c g2 r ko*pg+evf+pj /4qs(ls0uzossible genotypes of the biological father?

  Which row shows the correct ann* z66 bs0c6 g9o9kapa+spwgeiso4)k l4)jkv fotation of the alleles for blood groups?

  Which of these statemey 5amb/og-qg *nts are true 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 celld c;.c i*:zzqgfx1 tb9 anaemia and the spread of malaria acroxq 1.*fcz :9dzibc g;tss the continent 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 cola(a6 zo3h wus0our is determined by 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 (zu3s( hw0o6aap).


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+my7i)yc q /gm86bzo20 mugcm genes.

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

Sickle cell anaemia qfo 691gpgz rh4: (mbh:/cwkbis caused by 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 betweenyvqp, o.1xf)j mus g37 a male cat that is homozygous for brown, long hair and a female cat that has black, short hair.qu1j o37gxvm., ) sfyp


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-sij p:4,.i kg2ak* tfxahaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant oj4a.:akift,xgi p k*2 ver 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 hpn69r hw3+ pbvair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross whn r6pw+9v3p bas 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 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 shoq yw bbb0*lvka95x2n;wn in the pedigree chartw ;0 2k 95banvb*xyblq below?

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

  Which of these statements about genetic disorderwn (3-of70 l8x -ex72 zkcfir-o pnfnys 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 can shw wb,ho zwbn6b*(: :hdow 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 diwr2edkz6r o* gfg p7tk.2(u(zsorder shown in the pedigree chart is X-linked recessive and not autosomal recessive? r7w (ko(z r2t*kde.2 gugz 6fp

  Different species of livinelb4hf/dt c *9c/olw*s3(le dg organisms have different numbers of genes characteristic to them. The table shows the estimated number o c(l*o d les*he/c wd3fb4l9t/f 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 flower colour. If4(q-4nmwxd0bntg2 (r1i7g nt dk a yk0 the pea plants Mendel was studying can only be white or purple and follow the rules of Mendeld(0 4tbg4dn-n0 17nkka2irqgx ytw (mian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female withoujl., eio j64e lb,yv4uz .*miit hemophilia have a du,4e. 6m 4ybl i*jjvloe.,ziiaughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out betwev4yall3 twu*,k/nx3 )gn ,c hfen 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 0.033n )cu4t/*x lng whf,yklv,a5 significance level was 7.82. The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A and blood type B can have a ci,xe jxo0z*94i0 iyuzhild with blood0ixixio , *4z0ezju9y type O.

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

3.Explain the role of inheritance in genetic diseases.