A man and a woman have a daughter and a soncim 6ulsy-z ; kyy0)ft. /3q.fyactd 2. Their daughter has normal vision, but their son is colourblind. Which one of these yt f /);fy6-. 02dz3 .yltccmuqkisay genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a helvz7jvhu g+ c2,z )4duman male?

  There are two alleles for flower colour in snapdragj*uzfv/p ,2+ u3k 2ehpwg:u cnons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink fl pgezw,2 c+*vh32/jupfknuu:owers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct d6w :rgqugvhanf7( *t if/q8 3e uef;;kefinition?

  Which of these statements is a correct dwtf c+vvplo- 26 rz((yefinition for a gene?

  The diagram shows a pair of homologous chromorn ek*g0z7z 6 dlgr1+nsomes.

How many loci are shown?

  Two individuals, heterozygous for a specific traix6 yrx3*av rwo0tjya, ame5;2kl;u +m t, were crossed in an experiment. Which row shows the expectedrayx uje0 yo+a*m 23;r;,am kxlw5 6tv phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a bandedx/yxwkncpy7y(: uhzypg11/ +ybef : 1 pattern. The nonpnyh u1 :(cp+:7yk/x/gb yfwxe1yz1 y -agouti 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 individ 6ehzg8) 1:as9*x ujz yh(ab8lbkgpd2ual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and hygdl 9k)bb18ajuaz spg*6z2 (ex:8h 105 offspring with wrinkled seeds.

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

  Neurons of the fruitv+ba:hqf 7y:s4 n0 e9leq9fyi fly (Drosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fruita0s:bef4 : feq qn +li7y9y9vh fly?

  When does the random orientation of homologous chromosome paiow2hgd7allk p7d7z)ri4 99ekrs occur?

The majority of the genes in the++uvjw83ez9 p) ;tfu0eabgy- ynu7 yd human genome have already been mapped, meaning the exact locations of the genes on chromosomes are knoapbeyv+ ;unugzj 809y+ye d - w7uf3)twn. 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 linked gesm 3ynb3: 2w23f spakxwnl na :s(,y3 iu3jm*cnes?

  The diagram shows a karyogram of a brown male rat (Rattugf ,zb5h+zsucc ffl* -)s*j0ls norvegicus). Which arrow is pointing to a pair of )jz,sfl bul*0+5 -ffhz c*gcs autosomes?

  Mendel observed that there aryd+j0yk2:lcn e4d.t le two possible 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 of the pareen+. k0dlljdy2 :4 tycnts?

  The graph shows the frequency of birth weight of children born in London in ( 7ii4xesh1 he:rcmbqi (*ruf-a 0g- m j0at6h1991. 0r4mtmaqh0:6 ih( s uia 1fb(*ceie-7hgrj-x

  Which of these traits is an example of c5ize8mpxj4 2 aontinuous variation?

  Which row correctly describes diploid and haploid cells in humnz6 si;e3s en. bh.j2yans?

  The following table shows the diploid chromosome number of a range of specna6,fnx;w dvi/ kasl ,r8nl,7ies.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive alle k -96lottfuxz (e5:q il 18dxea:c1umle (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. What2p9rfx8uj ka9u2-of u are the possible genotypes of the biological fatheru2 f8jkx9a9fr p2o-uu?

  Which row shows the correct annotatio-b .j/ p*jjrbxn of the alleles for blood groups?

  Which of these statem(-7umgo,zml)xmkwt 3.y8 pqbj ad++zents 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 ay-vib)ostxxm q n/6 v*e1+ dcs w6u(1pnd the spread of malaria across the continent of Africa. mc 1qsx1*w)y-(v px td+b ine/6suov6


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 (8 (4ndhal7phq:sd dg 7Equus przewalskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) a d87ga:n(7 qs4dhphdlnd 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 genw /y:5*m gqbo6 wdmf4ses.

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

Sickle cell anaemia is caused by the allele Hp opj ;(wrv/7ei y9p(pb$^S$ . 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 fjrhe *eh*b8j+or brown, long hair and a female cat that has black, short h8h* j*b+er jehair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for d ebyfgasv;8h -trlo qx0+c;1 zs:q)n,iamond-shaped seeds (D) is domifsgyev;a 8cnh lrb: + zqt01qx )so,-;nant over oval-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 hair (L) is domsl9m7wpn7wa 2 inant 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 n297ww 7aps lmand 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 1ma m3rd em0fzn qm)zoy:+dv1n,6 9gkthe condition shown in the pedigree chart below?rm,mea)ogn0dvmkz 1:3 zd 1q fnm+96y

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

  Which of these statements about genetic disorders is/are c b8pajook0oj4jz f :..4kwl2 yorrect?

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 distriyjjf 5 u+h7 9cacd41fbcjl;4w bution.

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 the9rptl( -+jyss1uo- ot(t hc +n disorder shown in the pedigree chart is X-linked recessive and -(t js(hy1n+stopru+ct o9- lnot autosomal recessive?

  Different species of livingp3pf:ysipz0.y s(o4 n organisms have different numbers of genes characteristic to them. The tablpso(ny40f.py3 z s: pie 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 flower x7:u nzidx u.q4x7pp6colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of tp6uxdq 7. uin:xzp 4x7hese statements was correct?

  A biological male with hemophilia and a biological female without h zf* mksx,jw m,3q0p/zemophilia have a3qzkm,sx*p/0jwf,m z daughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carrie2)7vkfygys3/gcb5 qa d out between two sunflower 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 b gka35/cq y7y)gfsv2. 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 have a xh(qns,xxf m.zkm,0k-j6gm-child with blood typesmz0,n,(fmm j 6k x.khgq-x-x O.

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

3.Explain the role of inheritance in genetic diseases.