A man and a woman have a-j,j t2ygg)fa daughter and a son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biological 2g)ajgf -jy, tmother?

  Which diagram shows the sex chromoso0gopg/p ay26rn1o0 -ipx f /bames of a somatic cell in a human male?

  There are two alleles for +: ijd2z ;dxh/5smwvdw(dt f)flower colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offsprs5d 2t(/fddv )mwd+:i zhxjw ;ing with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the cokq bq75lcn4:awq7n *e rrect definition?

  Which of these statements is a correct definitione9m;b9g+ pu yc for a gene?

  The diagram shows a pair ofg ( 8)chsfilta k,n.wft89a8k homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific t-r dno2oq:v7trait, were crossed in an experiment. Which row shows the expected phenotyp:2d-oo7vr qnt ic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have imkta/;n0h r(( onq)ua banded pattern. The non-agouti allele causes hairs to be a single colour. Individiaq)nkr( h0n( /tu;m ouals 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 s(x, q j6 xfcsi5zvr0lgs-6cd:hape in individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring 5xrsj(zlxsv0 ,i6c f:c-q6dgwith 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 melano;6.bntexx3xy- bohq86gn a/w gaster) have 8 chromosomes. How many chneyx 6-8hx6x.wob;3/abn qgt romosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientatins:g1x /faks0on of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped, meanmq4lmn486*xgy1jxv7 uxl3 f9gu;eb z ing the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of chromosomes.96lu* 1xb4 q3xmy47ulj ;emfgvzxg 8 n

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 2+z 9d +.swg mlvvcj9xlinked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norp r(k),qj:s xm.:j0bf:f7kj u tav6yj+oh6y lvegicus). Which arrow is poin6 s:7jtbk::m ypjj,xv k ffhr(+)jqoa l.y0u6ting to a pair of autosomes?

  Mendel observed that there are two possible variationo+8ily4/iyvlx-px 2xp lk1p /s 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 tp2xvo4ili1 /p/-xyl+ kxly8p he genotypes of the parents?

  The graph shows the f:o wrs,c.pmlb7 w +yg2requency of birth weight of children born in London in 1991gb 27ro:c+smp ,l.wwy .

  Which of these traits is an example of continuous variati l49;/b8,xblxqj wmzx on?

  Which row correctly describes , z*4 sfiu wq-gx ov+ttnc01g+diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species. iv n )mz5lq+5kuxxc7zb m+8f9

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessk.,k oerqmf;o.ci)wvm)ir (- , df9qyive 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 child armw/cf m g+2k z1s5x1mp95x y -sncp0with blood type O. What are the pos/1p ynfwm01gxpz 5xmc-r 9s52 ksacm+sible genotypes of the biological father?

  Which row shows the cor7zn +h(( qzu50mwn kzcrect annotation of the alleles for blood groups?

  Which of these statements are true for allelkfb nwt5.1 2)ysgf jrxc33q 6yes?
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 in; (8eb bpt,7q,za kohpcidence of sickle cell anaemia and the spread of malaria across the continent of Africa.z7 bpo,pt ;q(8ka hb,e


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 determined by a numb ux+a): wtq:wkcvuctbd4.u24 er of genes. Brown colour (B) is dominattua2)qc:d v. bu wwx:4c4u k+nt 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 unlinj ;ta) yr1mg3oked genes.

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

Sickle cell anaemia is caused by the albx,wygg)q(5m 6 wpb6dv9yv2ylele 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 homozya.hg1ml sjtfhl : fdywtv4p-y7.47 ,ygous for brown, long hair and a female cat-mhh 4fyyllf:,74pj7 vwd1 . astg.yt that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-sha fsp2 h:ryf bqg*7(/sgped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is domir sqg7ys *f/p2g(h f:bnant 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) sw dbi u.fx 6:8m.t.fuis dominant to short hair (l), and curly hair (C) is dominant to straighst x.f u68:bumw ..dift 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-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 ic-d lnpq;hj+ ,6ld;zqkrg k8:nheritance of the condition shown in the pedigree chart: j- q g,lkq h86k;c+nzpdd;rl below?

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

  Which of these statements about geneticmpl( f1p) 5 f9iqgar3i 0st:sx disorders 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 can show a noyi2go/nt *rhgl 7 )vhmc.yc* 6rmal distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  What suggests that t y8 fznw,/q6h,m0w qmcib-xc 6he inheritance of the disorder shown in the pedigree chart is X-link,/ ,whx-fcqizw6mb6nc8y0 mqed recessive and not autosomal recessive?

  Different species of living o8k;wt djdd93 on.q 5herganisms have different numbers of genes characteristic to them. The table shows the estimated number of genes dh8.o5;nddw3 kj9q t efor 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 colour. (ydro4 -em b0pIf the pea plants Mendel was studying can only be white or pb ey 4rp0-o(dmurple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia an5gx/m(e ;djdubu (a/ ld a biological female without hemophilia have a daughter without hemophilia. What are the possible e d/g; uju m(db(al/x5genotypes of the daughter?

  A dihybrid cross was carried out between trvtih 2ohy9+;-d esxm3s .lm,wo sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critic lmrsm9oivh ts2+-e dx .yh,;3al 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 with blood type A and blood type B h 79o6dqfe(fs *;uybf can have a child with blood tu*;y feq b6(9hd o7sffype O.

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

3.Explain the role of inheritance in genetic diseases.