A man and a woman have a daughteulcx,d( /gwh u(r 0u6 z g .nouver(./mhex;*xr and a son. Their daughter has normal vision, but their son is colourblind. Which one ofx*l rgwnuvughz/,x ;.e6 ho/xm((c . u( 0erdu these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human malvd+u w2 0j* w: apx:il/lzc5lv4ln i5ve?

  There are two allelesizy sls/p3mj1.) yml4+ ly)mv for flower colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed 1/vl+yjm)mszlpsyy .lm4) i3 phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched togq;t 17, v3(jzjrri qmj,eq( s the correct definition?

  Which of these statemenwl mjz/c;x,)xqwl n i td*l-oy 7g-,2cts is a correct definition for a gene?

  The diagram shows a pair of homologous chromosom64z5 ruyer ;tqes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an experimd+rrmkz l m2pdcfw0/2n; 8e2lent. Which row shows the expected phenotypic ratios of the offspring resulting from this ;+rm0w2 lpldec8 2rfzd/2nmkcross?

  In some animals, the agouti allele causes individual hairs to have hs 2 k+isrl4vzz*a8n+ a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs with al+4+zis8svr*k h naz2 banded pattern.

Which combination of parent genotypes would allow for production of offspring that do not have the agouti characteristic?

  Mendel observed that*2( i f8fr7nyzb cirskr;xsu02f l* 1e the seed shape in individual pea plants was either round or wrinkled. The;* s u7r8fci2i1rl*(ersfynb 2zkx0f results 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 melan8br1y lqj3( xxogaster) have 8 chromosomes. How many chrx3jby(8 q1x lromosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome pai/l.ayp,; t29dsxrzes rs occur?

The majority of the genes in the human genome have already bvq,ycp 7t*+z;5novszeen mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below z 7yz*q +onps;v,tc5vshows 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 ic9z* dqq rvb, -bcijcqp .c8//: x2urdefinition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus jhf18 bwe jy /7m-yyza x7s44lnorvegicus). Which arrow is pointing t44 7 w8mshyj l1y/-zaejxfyb7o a pair of autosomes?

  Mendel observed that there are two possib7,jzafan/5s cle variations of flower colour in 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/cz57 a,fna sj of the parents?

  The graph shows the frequency of birth weight of childrenj cx o)kssr9*w ; b*/laq3/ryb born in London in 1991 ;c yw* q r)o3/bs*ablrx/skj9.

  Which of these traits is an example of continuous variationddzg zg t0.;:n?

  Which row correctly describf3bt4 z6nc ol6fx):xtot 7)av es diploid and haploid cells in humans?

  The following table shows the diploid chromosome nu fbj z.ngxur +lc/e .nlw-y1;8ps-p7wmber of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive alleleynl5w/zq w;5 sy-p l)w (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 childk 0moy6o7 l2j 2ryeuco(;kj z0 with blood type O. What are the possible genotypes of the biologi6lm(uy ;j2kr 0o2zok7cojye 0cal father?

  Which row shows the correct annotation of the allelese+x v)6 5wahj e.mm emg-.,zqo for blood groups?

  Which of these statements are true for allel tkm-:mhwsl ; baf669tes?
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 thc4*c w-ex(fp*6p uu3eou npj, e spread of malaria across the continent * pcfc* ewuxp4 u3,opej-(nu6of 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 przrjgv9+ 2 a8tmdewalskii), fur colour 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 onemj+2vtr d8g9 a 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 betwee vm7bz)1gt5b* h epw)jn linked and unlinked genes.

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

Sickle cell anaemia is caused jg cy8j2oiruz,9w1q5by 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 between a male cat that is homozygous for c3e (2v qmd 7br5(rld-mtfx *kx* cq/uku1y0dbrown, long hair and a female cat that has 1 rxmkx 3d-*butd(d 2lvfk*7y5r0c(c qeuq/mblack, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diar7rb d u:zey :p;gz,2hmond-shaped seeds (D) is dominant over oval-shaz dyg;e:2z rhrp,7ub:ped 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), l/sd o;3.us,ozav rpbj3y/g si ly-71mong hair (L) is dominant to short hair (l), and curly hair (C) is dominjr/yo 7pl; ybg ,ui3s/v1a-3.szdo msant 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 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 chartr+e u.dwhf c9.za.xjj m6h0f8 belowfr jc6.0 +8ea m.fxdh.jzhu9 w?

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

  Which of these statements about genetic disorders is/are corg vg+d;l7q7h( uh9at f .obo*rrect?

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 jhn0p+/ccd*dd1r8e c 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 pedigrjrf sn92q. p2hee chart is X-linq2rjns.f9 2ph ked recessive and not autosomal recessive?

  Different species of living organisb hal)i1 l8 3 yckb;;xcj,x*vd/r6w vsms have different numbers of genes characteristic to them. The table shows the estimated numbe8sjlk,v x6 abvd)x*wl3; cycb1 /i;rhr 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 plqga g .e(p,rg(ants, including flower colour. If the pea plar(p(ge .qga, gnts Mendel was studying can only 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 withoo*gz ud6i56ip/c4 uxaut hemophilia have a daughter without hemophilia. What are the possible genotypes of 5 z6gucod6ix 4iapu/ *the daughter?

  A dihybrid cross was carried out between two sunflower plantv88kldndpe uc*, k q od7(*h4ss (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 hund, l88 de( *kp7ck*vdsq4o0.05 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 type B can ebp fr3n*5k o-have a child with blood type 3rbk* - pf5noeO.

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

3.Explain the role of inheritance in genetic diseases.