A man and a woman have a daughter and a son. Their daughter has normal vision,e(a*o gzqyabf)n h 9eg.,gs 7cw (1f1n but their son is colourblind. Which one of thes17 *9gczwgqfhoy(1nga n.e,e (a)f sbe genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somzn:e1hak-t n :b3p xx,atic cell in a human male?

  There are two alleles for flower colour in snapdragons. 0 ubs 9nnphhh 8th2o0e03pry -wqm7s0However, 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 tqe mh00 -bhpwy 8sun2s9op0h0 7 hn3rlikely explanation for this observation?

  Which keyword is matched to the corre+cf:qkzllav.; x u76i2rjr , mct definition?

  Which of these statements is a correct definitiqq(zfc0 o u8c5on for a gene?

  The diagram shows a pair of ho(n0vz)f amn,ad-xs.k-ag+ o o mologous chromosomes.

How many loci are shown?

  Two individuals, hetf vl*i- xdetk9wpt t;6(nn9j1erozygous for a specific trait, were crossed in an experiment. Which row 1v w n*t;-9n9k(ptielf jd6txshows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, thekre:t fj-9lff+/d )r x agouti allele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals wh-rd ) /9jleff:f+xr kto 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 eithelu3z ; :f9jeqfxiaq2(r round or wrinkled. Th9eqj ;lxau (:32zfif qe 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 melanogaster) haved0m)g ;t;6itxvi+:qhkmxy k + 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fr:i ++vymqxtkxt;hk) 6d ;gmi0uit fly?

  When does the random orientsw 5oanz7 nh 1l(y4d2iu0sd/bation of homologous chromosome pairs occur?

The majority of the genes in the human genome have already 09a rf;up/:9knwklav been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homolofnka:l r9kaw up0;9/ vgous 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 oi63fvj 8c6 ccof linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Whwl280br4t (fclh;t5pi tkfz82hsc c 6ich arrow is pointingh f;8crc2 (l s t8i w5bkpz6ht2fl4ct0 to a pair of autosomes?

  Mendel observed that there ar+plf/p+ndaox.jm0 , ,uyi3 se e two possible variations of flower colour in pea plants, purple and white. After a genet fxyslmod ,j++0e3ni/ pua,.p ic 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 frequency 2zi* ox-l4lfr ocgxehgom0:+ 2 :fp:y of birth weight of children born in London in 1991ho+ l*20fx-:yf rl ciggmz oe2p::xo4 .

  Which of these traits is an example of continuous variahis 5+ ab:9up2 n1haam: oj*ection?

  Which row correctly describes diploid and haploid cells isc.vtp31tikjo 8 1uq6n humans?

  The following table shows the diploid chromosome number of a range of specq+os+,zy r2kn (bhb8yies.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recuy8a)wzeod mo u ww7sv94 t142essive 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 hacga0 +b ;ys1oyd a child with blood type O. What are the possible genotypes of 1a;+yg scyb0othe biological father?

  Which row shows the correct annotatf/tqvj2fc vi -9xk*i :.oszj:9dl j/j ion of the alleles for blood groups?

  Which of these statements are true:e,8sun v rli) 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-44pb3ncx q sv the spread of malaria across the continx-n sq b4v3p4cent 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 eb i3;2gj0a a8xo.qrgcolour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b)2;ao80ixqb.a g3rg ej 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 linked and unlinked genes-fx n6.p2b-ikl yj.p5ti 2n9ml+ gi js.

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

Sickle cell anaemia ihya2n(p 686xo(4goom/a ckiq s 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 y (67 pmk9siyw fenlc.1d+7bnq3 lr9j a cross between a male cat that is homozygous for brown, long hair and a female cat thb37w d7 +ls ly6i9krn.jq1y9cn(epm fat has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacvqrc firj h 1, f8 3mtyx/7h1)p(eidcss 5;f1cum officinale), the allele for diamond-shaped seeds (D) is dominant over ocpfv(csiht, h/j8 iffsx5qrr1; d71)yc3e 1 mval-shaped 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 hairg,z3 (j/kq nrh (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-haired guinea pigs and female short, straight-haired guinea pigs and a chi-squar(hj,3nzkg /qr ed 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 c-)ajyavixl5i 99y( xs ygg8j*ondition shown in the pedigree chart beloiggaasy9v)5xy j*x8-(y j 9liw?

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

  Which of these statements about genetic disorders is/ ;xj56u um0*k8pkla2fbt 9udsare 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 show z;vve 4imprt228w bn )t:6eu ra 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 pedigr2at h-e k2s h-f/ksd+zee chart is X-linked-2e/h fka +sz2- tskhd recessive and not autosomal recessive?

  Different species of living organisms have differen4e .kpbj tl/z0t numbers of genes characteristic to them. The table shows the estimated number of genes for five spelptb0 /k 4jez.cies.
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 char .n ;comaoia*so2 nnw9a89r1eacteristics of pea plants, including flower colour. If the pea plants Mendel was son 9 soe;1n.28 na *c9waaormitudying 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 without hemophilia hav7z : g8:y5t+pcdi3nz -qenxhme a daughter without hemophilia. What are the possible genotypes of the daughi5 g+8et-z:37:mhczndnp y qxter?

  A dihybrid cross was carried out between two sunfphz-m( ehs598 fes o9uymodcqj p1 ic.:,, h)jlower 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 0.05 significance level was 7.82. The calculated value for the chi-squared test was 10.05; what does this indicaej j99ho, e.hcq)pdo1:y s8fihcm,sp-5 ( zmute?

1.Explain how parents with blood type A and blood type B can hapu bg k6btkkr+e0++y 6uz* 7v)u,rcctve a child with blood type O.rb7tt +e6kukp*b+)uk 06u y rccvgz +,

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

3.Explain the role of inheritance in genetic diseases.