A man and a woman have a daughter and a son. Their dauoam ccm1e/ b.+ i4(fsqghter has normal vision, but their son is colourblind. Which one of these genotypes couldom +c sfq1e.c(m4ai/b be correct for the biological mother?

  Which diagram shows the su5rquo2jqj c3i qwg95 vd8c 8*ex chromosomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. Howeve( gv(ri2uizh3r, the result of a cross between two hetegru v3i( 2(zhirozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matchr9f l1tpo zk.: h -ufb*ezi.;ced to the correct definition?

  Which of these statements is )dr /s6, ilw(xwmr gw6a correct definition for a gene?

  The diagram shows a p)r,mfe*a lj oyx8i2f7u*ph:blh w.m:air of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a speciu*3 i9k4tx)cx jovfw x ) er,.1q +pixh5se+ncfic trait, were crossed in an experiment. Which row shov+ , +9uj)ns x3k hr4tc)qxci 1oew.pxi5xef*ws the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele etz- pk,;j v1ocauses individual hairs to have a banded pattern. The non-agouti allele causo,jtp 1 zev;-kes 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 bppc;z) 7vg b2either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 off bv7bcp g;zp)2spring 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 8 chromosomes. How +9r)aawy6sy4ql oae c+3eo/ gmany chromosomes are in a fertilised oocyte of 9e ga+s +q aaoc3rowe) l4/yy6a fruit fly?

  When does the random orientation of haqo1p)x evssd51l / )6/*cvb ehdn6 soomologous chromosome pairs occur?

The majority of the genes in the human)snr 3 cyldtfz2h1 e, v,fdh:3 genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of chromoso,vs) zd1:chrh ft d e2y3,lnf3mes.

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 geq-y;8 plndx;ynes?

  The diagram shows a karyogram of a brown male rat (Rattus n u;y0v;xin yqp7f( ce1vdz3z )orvegicus). Which arrow is pointing to a pai(yf nz0vi p;)3uvz;xq7eydc1 r of autosomes?

  Mendel observed that there are two possibu,d2vtdk+9se j8qa l6 (:amr/lf ris*le 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 genotype:f*daq k eajt,8v 96mls+uir /2lr(dss of the parents?

  The graph shows the frequency of birth weight of chinim5r;i- 0of 7 4batjyldren born in London in 1991. oi ; ra75f- 4bi0ntymj

  Which of these traits is an example of continuu fv y.zrk(,+amj;l s3ous variation?

  Which row correctly describes diploid an)oqn(wwtjo5j :/0lzqdkss(h7z : cf.d haploid cells in humans?

  The following table shou3y ev(es3/(vb llfp 1ws the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is causeaxr9v69srpih /zr)8m d 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 uwq0s,0-9i v s6.fpf0fdyj jdmj; dc+ child with blood type O. What are the possible genotypes of the biologid +,v .mfp0j 9 yfsdfjciw6q;-d0us0jcal father?

  Which row shows the correjcw4 u lw )7-u6j; pdgxpi:fx:ct annotation of the alleles for blood groups?

  Which of these statements are true fo1l gwj1yhm;+kr 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 sprksfeh x*tsv pt:4/ ))enwyb(-me/ 2sfead of malaria across the c /nf(xpeyt)4) v*eekfs /bmh:wst-2s ontinent 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 przewalsk7d1 rpd*m0-xctu2,h poq j2sjqi - ej+ii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and ans+i qr-o*c jud 2tmp- xqp,d27jj0he1 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.rpb.m3- zq ax/ ni*a3v

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

Sickle cell anaemia is caused by the allele Hb. 8x2a0vy o8wlerp4bssh h4-ru. zyx;$^S$ . 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 .adzn ,ptv7a0male cat that is homozygous for brown, long hair and a femalnt 7 .0azvp,dae cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for dn8kyj)wihs:( iamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant ov)yinw :s8jh(k er 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 short hair (l),bdl9(ha yzy1xu 1u uh: 6s8kc: and curly hair (C) is dominant to straight hair (c). A test cross was carried out betweeu (: cy:zk1xba8hy1hls6u u9 dn 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 inh*y tcomy ;6yh,155dsiv cljx va+jc *9eritance of the condition shown in the pedigree chart belo ,s; *vijtxl y dv*+9mcch5ocya61 jy5w?

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

  Which of these statements about genetic disx ,dli(f 2n85g u0hpjborders is/are 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 tz2s3j j na-rj;raits can 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 inherahf.p:,xh+vykv 9ru lots:p7 ,,o xm 5 jmg06xitance of the disorder shown in the pedigree chart is X-linked recessive and not aul6hmxj 0k:,h t.vx,s +yp mpr7,gova5fo:x u9tosomal recessive?

  Different species of living organisms have differenk5cix vp (rz3zdaqm/3qj 5.9for a;4 lt numbers of genes characteristic to them. The table shows the x 5qpz3kfr;dcoja34i. m9 5av(/zrlq 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 co3u okkckri(,ma d-e ;f r5uxnm9:h)7haracteristics of pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow the i9m,uerk: 7md5h o;)nacx fok( k-r 3urules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia jqe,(bw d; h*oand a biological female without hemophilia have a daughter without hemophilia. What are the possible genotypes of bjq(h weo;,d*the daughter?

  A dihybrid cross was carried out between two sunflower plants maogzxu5 xzcy4, 5;y1 (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;oyx,1z5; mgzuxa54 y c what does this indicate?

1.Explain how parents with blood type A and blood type B can have a child wi 68ofdt-n s7u hkf/c*uth blood type f7ous/6-dfk cu8th* nO.

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

3.Explain the role of inheritance in genetic diseases.