A man and a woman have a daughter and a sonnx 2 ,7;wblt-mf pra+g. Their daughter has normal vision, but their son is colourblind. Which one2+a,xftrnp-l bwg7m; of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a hum)+bn ,7lfbe 1 tc6csugan male?

  There are two alleles for fl /zd4rb.9 wcjmower colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with t4/9 wjb.cdzmrhree different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct defi)0ukw 00 r(+1zj m4stkw tzijbnition?

  Which of these statements is a correct d;nv;;gn j/afdefinition for a gene?

  The diagram shows a dln04x.g*7u90qi uf (eb irya4o d0xwpair of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for-ncrw0)x8i r hs8jy m0 a specific trait, were crossed in an experiment. nyhr )j-xr ic8 s0w80mWhich row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to havi7cw 0rxnv+0w 6a2saye a banded pattern. The non-agouti allele causc7s0w+ in yvxaa620wres 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 either round o*h7*vj4 1fzlk d9jmnsr wrinkled17sk j*nld f4zv*h9 mj. The 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) have 8 chromos14lyg4dd*gl uzsym1ry*i+ 2 jomes. How many chromosomes are in a fertilised oocyte ymd zlr udgj yg11 4i*+y4l2*sof a fruit fly?

  When does the random orientatf7h 1 8*kdbdfsion of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mn ogo 0tc;)2rymt:me)apped, meaning the oc2)rtg0t oem; :)ynm exact locations of the genes on chromosomes are known. 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 linkexqq8s v8i ,5rsn (u fq:37tpskd genes?

  The diagram shows a karyogram u/j+kg dnee0j y8e73 :ahc(bdof a brown male rat (Rattus norvegicus). Which arrow is pod(0unc/j jb:dh3e7 8a+ egekyinting to a pair of autosomes?

  Mendel observed that there are two possible variations of flower colour in peaybreyp 0cl ;epx+i6dm u q.7,9 plants, purple and white. After a genetic cross, the ratio of plants .+ ex79edby6qr ;p0miu,l cypwith purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of children born indf-m;y imj-la8b s6p0 London in 1991.dlsmy 6;-a8jfp mbi0 -

  Which of these traitt:akbnd.- s s/p- -jqys is an example of continuous variation?

  Which row correctly describes diploid and haploid cel;kqmhrf n8wd.8,i2 g8 q4eoxals in humans?

  The following table shows the diploid cb:z i--xukj/ dg x/3v9)gpxgm hromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia ic5ld ,rqvq w.*s caused 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 woefp 3s) :f )ge0wce*zyo/e( a child with blood type O. What are the po :s*f(zc/e)ow)o 0gpy e3ef ewssible genotypes of the biological father?

  Which row shows the correct annotation of the alleles for blood groupsfke bza- v dm95;7exe0?

  Which of these statements are /c p4qce,q5v)he)q pvtrue 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 sick2 amtibc1ti37 u c-*rxle cell anaemia and the spread of malaria across the continent ti mtr-i abu3xc 2c17*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 przewylyh2 ;ii f2jfj b775aalskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an 7yjj;i i ab2yff72lh5ombre (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 l lb;4)nataqd +inked and unlinked genes.

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

Sickle cell anaemia is caused bd+5nolsqf8, y;p dy .ly 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 cat that is homozygous for browdx+u idwi 435a zl/bfte-t*:zn, lonzbdi 3l*wf+4:-dz5t ixte / uag hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinatdptn1b(/:f*wv n p 3jle), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant owj(n/3f tnppd:tv1b *ver 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 m oa7o: hg:amgj7jd og*xj3x0b1e 7f/ (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-squared test (χ2) do7*/eh:1gaa g7 gj xmjofj07:m3oxbwas 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 conditih 2i*b 8knr s228*jr.tb yrj:-zofswjon shown in the pedigree chart below? rj.krz * -i8bo *:j2fj22bsywhtsn8r

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

  Which of these statements about genetic disorders is/are correct? 3 ;tgw; d7(5xy0fkhgvl3n csb

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 nj +gbo1)pm+m traits 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 inheritance of the disorder shown in the ppqv i-c3t7o,a 9t4vyl:anfe1 edigree chart is X-linked recessive and not autosomaa:3lnyp94ot1 c,vq7fi ta- evl recessive?

  Different species of living organ53.r9bzoq zv7oo - wklisms have different numbers of genes characteristic to them. The table shows the estz 9wv k73q bo.oz-5rolimated 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 e+kwdm )of4 a m.2+q.olu8rlucolour. If the pea plants Mendel was studying can only be white or purple and follow the+qmwdl2ouk)8o .+ 4ae . lufrm rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biologic f*wz 1il87 cu2f4tfiq b,2poeal female without hemophilia have a daughter without hemophilia. What are the possible genotypes ofoipec*7tf if,814uf wl z2qb 2 the daughter?

  A dihybrid cross was carried out between two sunflo ;yh 1lul:nw,ksn9e)o wer 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 inl:s;lh1 n, w)ku9eo nydicate?

1.Explain how parents with bljgz7bt ,/o *uq 0y0lxnood type A and blood type B can have a child with blobtxo 7z/q0n0 u,*jg lyod type O.

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

3.Explain the role of inheritance in genetic diseases.