A man and a woman have a daughter and a sonskdm)btskp135kvzzf- -k 0t3 . Their daughter has normal vision, but their son is colourblind. Which one of these genotyz s50kb)3 - pt3df1 kvtskz-mkpes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a h)0ex(hgu -pjywg k9 cz zm08:euman male?

  There are two alleles for flower colour in snapdragons. How/n75i;wg:lc xnxteqtz(e g.1z( at u; ever, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this obzux;z:ia( wqg 1n/;tec5n x.7gte l( tservation?

  Which keyword is matched to the correct definitif ) xpq:y dmvje/9 7s2,e8ddtwon?

  Which of these statements is a correct defif:.po6ta3o p0zb y*g*f kutmtk8,o0 o nition for a gene?

  The diagram shows a pair of homologous chromosom-eke7i/mz+ju-6cz q kes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an lan,w5 :6wc2 h:vcskmexperiment. Which row shows the expected phenotypic ratios of the offsa2:6n lkc 5cwhwv: ms,pring resulting from this cross?

  In some animals, the agouti (ehcq1f o,47 uvk( ;orbr.i ntallele causes individual hairs to have a banded pattern. The non-agouce r.uhro vbo i1f(7;nqk(4,tti allele causes hairs 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 either round ojl,gspr;a*6pc/p yx 7vh t u*fg(3 c8yr wrinkled. The results of an experimental crojcpyc ,utxp*a l83gfh; sgp*7ryv(6/ss 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 (Drosophijkzaiki pc-)),8d*jd)0x nmh, gxx4hla melanogaster) have 8 chromosomes. How many chromosomes are in a )ihpakgd-kj8xi ,x,c)0xd ) *4 jznmh fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome pairt+q 9u/0bas+fwu6 is7 u r:uess occur?

The majority of the genes in the human genome have already been mapped, 69f1y-c:khp*cnvuq ,x vrf;/sdxy+ gmeaning the exact locations of the genes on chromosomes are k, */ psuxvnvcyk;9hqy+:xd61frgcf - nown. The diagram below 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 definitiozmwnf*bo (zja),t o ;:n of linked genes?

  The diagram shows a k8xp( 4m-,r:ie-g n rrbo7rkq* p/estmv4nt 2faryogram of a brown male rat (Rattus norvegicus). Which arrq*i r-xnt, s(m-eote7rb 2rp :f n8g p4rvm4k/ow is pointing to a pair of autosomes?

  Mendel observed that there are two possible variations of wrrch+-) , n0amghye4 flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:cm,hey0) n+h rwar -4g1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of children bobcst 4elo:5424 sm856kwzts he w mb;rrn in London in 1991. s5w h4z44 8tm cbrbe6 le5m 2sowks:;t

  Which of these traits is an exa0z4 ie94x9 egnc lhye5mple of continuous variation?

  Which row correctly describes diploid and haploid cells in hub*7uz8w .qry5 u, crvrmans?

  The following table shows the diploid chromosome n dj; bxcfum.kb0*v4bt; gp73wm. lcn:umber of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is okr5* 2j38teopnei9b caused by a recessive 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 wid*f+ usrno,:8o. fhdrth blood type A had a child with blood type O. What are the:d+8fhrnsdu f o r,*.o possible genotypes of the biological father?

  Which row shows the correct annotation of the alleles for bloo( merluouv4d 8*cqk0a u+r2 a7xqs/+ad groups?

  Which of these statements are t3q /n :frtsz(t6qo0e4( kpxc 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 cell anaemia and the spread of ma;va)85mrchua laria across the continent of c h8aa)vu5;rm 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 0 h/wi )(ux5:y+ul gu2 hgnvzea number of genes. Brown col zgh gu)xe0:lu(2 /u5n +hiyvwour (B) is dominant to sandy colour (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 lqf +bp*k0ix- h .mmdwfko6s; ,inked and unlinked genes.

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

Sickle cell anaemia is caused by thebmxu1z4 m+sa) hvobsr.mn2 )0 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 xpr1+c(2 j;mql1 rh 36vcavfq between a male cat that is homozygous for brown, long hair and a female cat t 2l63qfchr1+jr q1xvav;mcp(hat has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxac d )):mf2rdkexxur w uk))*(vqum 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 u)evqwkux)kf( mr: )xd )*2dr 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 porcellusus0fbvc,ike9 mi jvlh 4867br6ee 19z), long hair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried outkirz 8s u0bef69v6hijc9 4m 1ele7, bv 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 sho ht55ej vk/0sfnbw80awn in the pedigree chart h0w a f05njsve/t85bk below?

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

  Which of these statements about genetic disorders is/are corqw)d7l6x,gwmwkb wp03 :(q xarect?

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 show a normal distributiok ;kqi z,m(+m ;ek*als*g(ahm n.

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 disfvu r; d(l*rvy+th09 yorder shown in the pedigree chart is X-linked recessive and not av(9*h +0yl futyvd rr;utosomal recessive?

  Different species of living organisms have different numb+ai*q qo+o2lxauy-c6 b+0qecers of genes characteristic to them. The table shows the es*u lbqciq+aeqxy+o o 62+0a-ctimated 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 flower co;rtk--xsa9b fw,r 1c ilour. If the pea plants Mendel was studying can only be white or purple arc --9,i1 kr;s aftbxwnd follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female withou rq q.ya8sc6d2tnk sk;j76f;nt hemophilia have a daughter without hemophilia. What are the possinjacnkq.6y; r;kqfts72 68sd ble genotypes of the daughter?

  A dihybrid cross was carried out between two sunflowp: usmd:z *1eub:o) bker plants (Helianthus annuus) to see if the genes for seed number and sezb:e*:)opbsk mu:u 1 ded 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-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A and blood typeoly.pu:y: 9 nlh 30mwh B can have a child with blood type Oholy.h 3:0pm: uwln9y .

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

3.Explain the role of inheritance in genetic diseases.