A man and a woman have a daughter and a son. Their daughter htus p-wfoj /9/w 0akakg9( m3nas normal vision, but their son is colourblind. Which one of these genotypes -mf wj w/n(9 a 3guopkkt09s/acould be correct for the biological mother?

  Which diagram shows the sex chromoso jnxcletp48 ;+mes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. p -qj(ze rdc4tmk)o ;)However, 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 obser mj-t)) ecrzd ;(qo4kpvation?

  Which keyword is matched to q(qbq-uc(b jdtm be3-sj:t 4-the correct definition?

  Which of these statements is a correct definitioappn(3jz yy6ztlj. z)s: 3 x3vg9ru;a k.g8gon for a gene?

  The diagram shows a pair of homologous chromosomes -xnazyo+f( 2/.uc,)vd sin us.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed iqdgt 5;t. nu4qn an experiment. Which row shows the expected phenotypic ratios of the offspringt5 dq gq.t;4nu resulting from this cross?

  In some animals, the agouti allemo 9 dd)sq0a+ne;;sl wle causes individual hairs to have a banded pattern. The non-agouti alln0;9w)md qd;aos les+ele 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 eitcx,rf 2 /3qadkher round or wrinkled. The results of an experc2,k3xdfa r q/imental 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) have hufe 33c;mc)t vc+(e mjn*()wuy k h0x8 chromosomes. How many chromosomes are in a 3;exnhc(w *hjc()e +m cumkt) fyu03vfertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromo ow93fym838:z-l o f tx1rybh/ubn.f rsome pairs occur?

The majority of the gern8:pdd l y*z+nes in the human genome have already been mapped, meaning the exacpy d8:rz+l*ndt locations of the genes on chromosomes are known. 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 definition of li6 ak178sqe *t 41frb)dsqdt qwnked genes?

  The diagram shows a karyogram of a brown mal+hde hfbg7s8/eahy2 2e rat (Rattus norvegicus). Which arrow b27h hde a/s 2ey+ghf8is pointing to a pair of autosomes?

  Mendel observed that there are two possible vvt*f pv4ol51 zykiu.(ariations of flower colour in pea plants, purple and white. Afte f4ilt(* 15ovkvpzuy.r 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 frequencyd.h yw-wfz udp0)s4 8* g.rzfa of birth weight of children born in London in 1991. w4pz*udarf) h.z s .ydfg0 8w-

  Which of these traits is an example2+qpjw/ bk/e l of continuous variation?

  Which row correctly describiy; ;ddh flaze x )v(yj9,ln.(. (vtfoes diploid and haploid cells in humans?

  The following table shows the vt;jgf7n2i a bh;(yu2 diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused y 2sf0z,qy4g9ehetl / 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 with blood type A had a child with blood type O. What are t5( tofp cxn62 qfx9;l4rv9wwrhe possible genotypes orn6 xcop2l5 wfrfq99 4(vwx t;f the biological father?

  Which row shows the correct annot),vztn( pn -2z ntfq b9k0f; 7is4oapsation of the alleles for blood groups?

  Which of these statements are ebvuilzy) 89,c c 6xh.mxg3oary;)f1true 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 m1)1:b)wfk,m; i u5u;yoobux xt y4z uvalaria across the continent of Africa.u k1wvz: f),x5t41;iyobub uu mo;y) x


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), .aenlg/ 7m+ex/ zto9rfur colour is determined by a number of genes. Brown colour (B) is domi7.emz9/ rl a etn/o+gxnant 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 d:6dptnc m5k0 b:p9rj*n q l,,tnp3vslinked and unlinked genes.

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

Sickle cell anaemia is caused by d,9ru+zk(, otsbu5apfbtk8 5 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 crcx-;iyeajdfx.ey6 0. 2kk5hposs between a male cat that is homozygous for brown, long hair and a female cat thatydp02k -exf.5h ejxi.;c 6aky has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacf:n/fbr d9 i5bum officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and tb f:9d f/nrb5ihe 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 pou y80xrg2h4d7 /k6t0ll/is9ztv5ea ua gfj -brcellus), 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-haire84y5tu fhjt0b a e7dgz-s9 v2g/rx a/ll6k i0ud 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 shown in the w),obp (andm8 pedigree chart below? w,( dpoanb)8m

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

  Which of these statements about genetic disorders is/are correc6dq l bfb;y,q 28d :7aki)nrvat?

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 sw:n)zzv 0k,j3; oum n(u slreva71o*ahow 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 pedigre o0z+(vjtjlm )e chart is X-linked recessive and not autosomal )(mz jtvl0jo+recessive?

  Different species of living organisms have different numbers o)j9,m6ps sotz +w7g4 cgeve4 bb45 ;7wfgjh mgf genes characterig5p6etw)4,7bgzb79; 4v4wmm ho gefsjjgs +cstic to them. 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, including flow;d mg3w)+)qto yft rp7er colour. If the pea plants Mendel was studying can onlwt )y)+dqr 3m7o;ptgf y be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophil-qkzl9 8emns,kgu,6 nepz8 c,ia have a daughter without hemophilia. What are t, k-, 9,q8nnscezl6pk zmue g8he possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus a7y b1vk by98r i(p:iv4rfwdd-nnuus) to :vrib 8vdd-(ryf7kibw1 4y9p 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-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A 0 q1bus i 43v1qyk6vtvand blood type B can have a child with blvvk sb6 43 vq1u1yqti0ood type O.

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

3.Explain the role of inheritance in genetic diseases.