A man and a woman have a daughter and a son. Their daughter has nor nl9bwcj 9 r(vkztl++c t4eg og4,-av,mal vision, but their son is colourblind. Which one of these genotypes could be corbegot-,4ll9(+wg 4nz,vjk c+tc9v arrect for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a 27a*y+ycun q dhuman male?

  There are two alleles for flower colour in snapdragon vq y07,jwfs0ys. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flower q,0ywvyfs70 js. Which is the most likely explanation for this observation?

  Which keyword is matched tokx8d y 8d(k1a4,bmibr the correct definition?

  Which of these statements is a correct de)9 jjqhjbz t1t 39fd(mfinition for a gene?

  The diagram shows a pair of homologouavqke d;f9n i0 s j,hc5bv7d.o 1oa0-sx8,jt os chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an 9h yj+zz br1.7msa/lfexperiment. Which row shows the expected phenotypic ratios of the offspring resulting faz+ srz /.h7b j19ymlfrom this cross?

  In some animals, the agouti allele causes individual hairs to have a ban:nf7v(r7yy1ge h(a r xded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who arey (e (1:ygan h7v7rrxf 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 either r. tuqzs6fa5k9yj2v/a ) :frpb wu,sw )ound or wrinkled. The results of an bj wts 2qaupu) a,rvk)/. 6z5ys 9ff:wexperimental 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 melanog*fe2 ,rj5t;6an dwu xqaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyteejar*;u ,n6 fdq x52tw of a fruit fly?

  When does the random orientation of homologous chromos-4lcw7 wll d34qfxmw6ome pairs occur?

The majority of the genes in the humanjgr5 ;k0wkb; z genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below ;5k0rkbj;gwz 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(-7m kuhz jm-l *lk;8athxxvf, 0zw2 rj3 f1ct of linked genes?

  The diagram shows a karyogram of a brown male rat (tucjc dq2i3 s ead,x9q r3zti-a,n8/ 6Rattus norvegicus). Which arrow is pointinrcxd-j e9da t iza,iq 3u2,tnq/3c68 sg to a pair of autosomes?

  Mendel observed that there:9d+3ggubwz0nim7 w( ypdv1 f are two possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plantg(u1n9vwmz 7 gw bif+d:30dpys with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequ05apow f2xdpsow8 i .6ency of birth weight of children born in London in 1991. w.d6 w8opfox0i s25pa

  Which of these traits is an example of continuous vari8dfn v 4 w*i9xth1x;vdation?

  Which row correctly describes dipl(k*kv dfg *mle:a sb.c- wb6n+oid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of s; if-,p8 rlbuwpecies.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allwq2:ga, )imx34fhwc pele (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. Wh 3o3 obcz:g2ucat are the possible genotypes of the biological fac z:2g3ou3ocbther?

  Which row shows the correct an +ag+hj1t5+ylvd31rxxm zp 2cnotation of the alleles for blood groups?

  Which of these statements are true for a7n wsla7b -s/v: zfck4lleles?
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 anaemin :a5xo5+ r(s+(mp0pqkryxie a and the spread of malaria across the oy an(5rkpsep( :+xr5iq +m x0continent 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 col hey,cew/ i8/jour is determined by a number of ge8ewi,/ ech/y jnes. Brown colour (B) is dominant 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 linked and un)4shsycg8li ,linked genes.

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

Sickle cell anaemia is caused )1v8f-cv3xg1cm3qnq s(tc 0;spse wg 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 a cross between a male catpdp351 8.cf l*u3m nkyg3hn bo that is homozygous for brown, loncu3n.51pfon8mdhg p *l by3k3 g hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale),g3./,rkdhfjv, ucc8 z the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele,,rg fduzc 8vhc.kj/ 3 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 nx++q *az*zwuvc -d ysk;cq(bg6gk r*i,h9g 1dominant 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 sg (cgbsz6qy g*ircw,-vku*;q1*k+ znh x+d 9ahort, 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 inheri-d wh1qze zc -vx5as0q5cj7j6tance of the condition shown in the pedigree chart bewjqz-x zc5 q0 v5cj7ea1 sdh-6low?

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

  Which of these statements about genetic disorders*y8gsy4 l+gdl i6c +k*dnmk 7g 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 traits cajvi*ijso/sp)3t*+ d an 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 pedigree chfsz k8v)zkl0 44 f9ho-7-no1nd spfvvart is X-linked recessive svl-4f 4nofk7 8zknov-fpdsz1h 9 )v0and not autosomal recessive?

  Different species of living organisms have different numbers of genz v(:uqz -tff-es characteristic to them. The table shows the es( tvzq:u-fzf -timated 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 characteristi:pp; +wx ,7kyfwek- yvv;pd2jcs of pea plants, including flower colour. If the je v;k-ydxp27wp+w;v y, fkp:pea plants 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 dfovm)nghqfk1 );+ adz a7q,6 and a biological female without hemophilia have a daughter witq,k) z+fom ;a gn7f)6 1dahvdqhout hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out betw )c e.tyc,vb ozm8odp* xe78w(een 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 0.07p (8y)e om ce.bwcvzd*xto,85 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 have a chi (4fbul37i d+mxzwuy 9ld with blood type Oilufwum3d4 y(x 7+9bz .

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

3.Explain the role of inheritance in genetic diseases.