A man and a woman have a daughter and a sonub1*feno kj,/gmb hgt55*b /q. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biologice1kn*b/ bhf/,uq o 5bj*gmgt5al mother?

  Which diagram shows the sex chrom+i:;xc(yl 0und sd ,wwosomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the result ofbn )enu5( ,mem a cross between two heterozygous plants yielded offspring with three differentemn)b,n5u(m e observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the coga yq0m2iufuu08 r): urrect definition?

  Which of these statements is a correct defi9,kb;8cb c2z ma zd2kcnition for a gene?

  The diagram shows a pair of homologous ch1uuuw*2/rk se+)kes v romosomes.

How many loci are shown?

  Two individuals, hete78bo-d sv;gn erozygous for a specific trait, were crossed in an experiment. Which row shows the exp8 g;obvd7 n-seected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele i)me *ni+t7b 55anvmxcauses individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs with a ban imtn+vnm)7ai5*5x b eded 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 plan ddjo:a4xrj11u2jl12rfr 2 yots was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offsprinrau4j1dfl2:2 dj1 2xo rjy 1rog with wrinkled seeds.

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

  Neurons of the fruit fly (Drosophila melanogamnzuf9*dks2/6 c o(rnster) have 8 chromosomes. How many chromosod6kozsnr*nc/ u2 m(9fmes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homol hw*er.acn ,b ,a;ct4fogous chromosome pairs occur?

The majority of the genes in 8 7tqfop:7o ddaf:g4 ) fxlkc.the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one represenc 8o7 fodd :katl47f )fgpx:.qtation 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 dv fqh(+w 5d,otefinition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). W4c sn,od7jnj+)gwhw/ hich arrow is pointjcw/,o7w+ nns4j) hgd ing to a pair of autosomes?

  Mendel observed that there are two possible variations of flowt.h nw0 8jfs9y bdgi,3er 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 genotysf bj g w.hti8y09,3ndpes of the parents?

  The graph shows the frequ oggdt (hu.0b6ency of birth weight of children born in London in 1991.oudg b60tg.h(

  Which of these traits is an example of continuous variatiot6 6y8izycfj d8r+dt7n?

  Which row correctly describes diploid and haploid cells in humans 6(; zihpba4q4 i8yqgn,n ej4ne(p5in?

  The following table shows the diploid chromosome number of a range wsdz+0 -aatin20o h ;cof species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allel m,5iyf1d)ma 2e ketna-hs :r)e (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 blooamd,x/*3r k y(:++ efkjthcwqz2m 9zld type A had a child with blood type O. What are the possible genotypes of te/(w9mj+a2*3cfdyxz kl r+q,z m kth:he biological father?

  Which row shows the correct annotation of v tbfn5r2z-l9 the alleles for blood groups?

  Which of these statemec; (n504szdzyzjf 6a knts 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 cell anaemia and urcvcdhta :34uxi8g;9r9vhbq0u w98 the spread of malaria across the contwc :893 v9 r4rtbavx9hu8uqh;g d0 uicinent 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 colour is determbajng-y*e h1-(g ptb 7ined by a number of genes. Brown colour (B) is dominantyh7 *1(g gpbatnj be-- 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 linb bv) q0,ag3 ;c zzq,;8ml;sup mtrt*dked and unlinked genes.

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

Sickle cell anaemia is caused by9 .dt f 3t) qtpkr1gule0p:sn6 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 fm9 m7uy:kg 78u6a 3qyidrxw k; cko,l1or brown, long hair and a female cat that has black, skq 1yx wgcul 3o k7k9d a,:yu7i6;rmm8hort hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allel a2mh6, knvyrel/i.m 1e for diamond-shaped seeds (D) is dominant over oval-shaped ye /n,r2 kavi.mhm61l 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 dominant to s8kame d ekz35 ry p.,-oh*uau8hort hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous loeydu mk.h8e z5a rp,*k- uoa38ng, 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 n f sxn30enk.p*4i (ut*w,q ytcondition shown in the pedigree chart bel*0xwkp. ne iu(34tqts f*y,nnow?

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

  Which of these statements about genetic disorders is/are correctl,m 3nf/0ktsk gy8 jiw)jbc7n ce0m-, ?

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 distrib*tup9ca+ k f2sution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  What suggests that thjc*c ls+-5ei ue inheritance of the disorder shown in the pedigree chart is X-linked recessive and not autosomal recesss*ceu l5i+-j cive?

  Different species of living orga2e0rxtjw2s1 s k2 3hbvfo 7gf.nisms have different numbers of genes characteristic to them. The table shows the estimated number of g.0o21jh7 fbge3xs r2 wvf2skt enes 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 flowe b6if,b0fcta3r colour. If the pea plants Mendel was studying can only be white or purple and follow the bt0 bi3 f,ca6frules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophaxo eg9bz3 5zzto5uh sqp5l9 (vc18 t/ilia have a daughter without hemophilia. What areotczqo5e3 zuz pvtl5 a5/bx91h g( 9s8 the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plant9s lyo4 :qoqs:s (Helianthus annuus) to see if the genes for seed number and seed shao qs9s4ql: :yope 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 with4l .tm+/pl9b37w:c:as tb 9o k6ygmesmi3b mr blood type A and blood type B can have a child with blood tym/b7:+ eibc ysga4 tmtlmmo3s 6:.r3b99pkwlpe O.

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

3.Explain the role of inheritance in genetic diseases.