A man and a woman have f)zztleq(u3he *o2h 8a daughter and a son. Their daughter has normal vision, but their son is colourblind. Which one olq3e8efu z2 (*ozt)hh f these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somwr8ua/+3 qzjmatic cell in a human male?

  There are two alleles for flower colour in snapd(sx031d3pc blnc rvhyumh 5- *ragons. However, the result of a cross between two heterozygous033v-h *crxl1p(n s huy5cm bd 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 matched to thmizg74z48 qz/5acn gie correct definition?

  Which of these statements issf fsm1cwes3s/a w29 82ue76yritg u7 a correct definition for a gene?

  The diagram shows a n7kgg/5b b ((dby9k6x(yzyy epair of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an experimesc;:gtlt 1o0a mwn u(-nt. Which row shows the expected phenotypic ratios of the ofw;og1cu(:tsm-tn la 0fspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to haveipqm ; bl.1r2ji:m ,k .f6iluz a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have m.1 lijb izkilr.q ;u,f:mp62hairs 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 inkdvyw sg+63-w b.qu/(ta2 t fp individual pea plants was either round or wr(.gqytw/ -w+v b3dp6kutafs 2inkled. 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 chromoso g;ltaotlrzy q)zha/5 :) k*p1mes. How many chromosomes are in a5g r:/tzkl;p*y )1) oalz qtah fertilised oocyte of a fruit fly?

  When does the random orientation of homolor59zj. a( ycx gkdr:*qpk dpq-/; .cbzgous chromosome pairs occur?

The majority of the genes in the human genome 4z 1ryqms*bfs n:(lux: )s-ofhave already been mapped, meaning thesm*14lyn)rsfx u:bs:foz q- ( 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 dnb 5gfg9-bd v,efinition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Which arglcyaqw-dk07*nxg: uh21cp 9row is pointing-0n kggdh7xyc cw 1q :lu*p29a to a pair of autosomes?

  Mendel observed that there are two possit i:ex ian8r)uv9/9 wbnb)r7 able 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 pare vn9e8 n/xrbt:a)9u)w ar iib7nts?

  The graph shows the frequency of birth weight of children born in London in 199:knn-4 sm4gkjcm - ub4x1dgu81zr pd11 p:dd 4rm81zmgujk-n 141s 4gnxbk-uc.

  Which of these traits is an example of continuous v4ntfjm q0up;cma0/a: ariation?

  Which row correctly describes diploid and haploid cells in6r quwo2 f,nv4 humans?

  The following table shows the diploid chromosome ywp 2/vx0fb6)dd; c rknumber of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive alle),zp+y9fov(ipsq ) rdle (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 hamxd :t2 jgr3c.e+-qy y7f2an yd a child with blood type O. What are the possi:a2yg-yde .nf3ymc2+jq7 t xrble genotypes of the biological father?

  Which row shows the correct annotaj zxz8n;oq35 rwn8s1o8 k2pfntion of the alleles for blood groups?

  Which of these statements are true for alleles? 6v0yctp 2hlp.
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 /zt8onp/y9f yp7yi;d6 gg. susickle cell anaemia and the spread of malaria across the coyu 6 fs.n gdgypz/7/oy8tp;i9 ntinent 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 colour f5zzh3e 6qn,n9v( nfgq3ch3f is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone)nc6h33z nfz ,hgf v(e fqn5q39 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 link8z e9d)lvxa5 ded and unlinked genes.

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

Sickle cell anaemia is cauk i2(-dhl63za ux9gdqsed 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 cat ydjxwev:hj o a)m99f/6 9ukrti-1r s) that is homozygous for brown, long hai9 6ri )kwu /:9)av1mrdty j9ojf xs-her and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped m0bnn/k1gt tj: ncj,-seeds (D) is dominant over oval-shaped bt t /-m: ,jgncnk01njseeds (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 dominant to sjny*/fdvy p/r48j e o (hh;q/xhort 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;*/ vjdypj q4fx/hrh /(n8oye 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 inheritance of the condition shown in the p m0l:j yu.l:h a/hiqc1edigree chart below?lh: 0my1/:h u.ilc aqj

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

  Which of these statements about genetic disorderwdpx vo, mvm0ce,2k71 s 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 8mzqo.+ lp:qb v0j(crcan 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 yh5x slq,ywp+h-/ ;vq pedigree chart is X-linked recessive and not autosomal recessive+hq,l- x yq5h s/vp;yw?

  Different species of living organisms have different numbers of gel5wxz;h uls0lw.kw4(nes characteristic to them. The table s k(s5; x0llwwl4zwhu.hows 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 pea6vmvc 4d 3,wrk plants, including flower colour. If the pea plants Mendel was studying can only be white or purple vdm c64w3vk, rand follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a bp6.grz/))lqp ln pwc/iological female without hemophilia have a daug ) /6zgrlppwqlc). /nphter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunfloweuva(( hi3nfwwg53 p /vr plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical va3u( ah(invw /v3gp5wflue 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 tygnm/ ;uy, ci,-rbh 9wmpe B can have a child with blood tyc9nr,y;iw-/bgmuh , mpe O.

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

3.Explain the role of inheritance in genetic diseases.