A man and a woman have a daughter and a son. Their daughter has nqlo* .k 1vaj9b ;es8gge4gqd+f v h+s,ormal vision, but their son is colourblind. Which one of these genotypes could be correct for the biological mo1,h;+ 8goaq +.fgv*jsv glsbq4 9kdeether?

  Which diagram shows the sex chromosomes of a somatic cell in a hupyn s09u(3ohw4/hc*rtk u 9rtman male?

  There are two alleles for flower colour in snapdragons. However,j3.ro1ow*x r mkyy w-5 the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explao3x5y wjk1- r.*ymrw onation for this observation?

  Which keyword is matched to the correct definitiov 4x3a:v :cj0+tmwyklmoxe5th a c 81t3ta:6bn?

  Which of these statements is a correct definitiog+l(u-0 rwl gyn for a gene?

  The diagram shows a pa0.n yl7yc cn)cir of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific th s(t. *3gr3jzd*ia2w - 3 xjwgj.dmosrait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting from this cros3jwd i*tazho3 (sx-.drw .s gj32*mg js?

  In some animals, the agouti allele causes individual hairs to havelmc0:jslmqgxen042 ) a banded pattern. The non-acl0lse 402:mxgj mn)qgouti allele causes 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 indvj( yd8z r9;,h l0sb 5/nowyrtividual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkllwrdyj;r/,sb( t9y 5ho 8vn 0zed seeds.

Which row in the table below states the most likely genotypes of the parents?

  Neurons of the fruit fly (Drosophila melanogaster.llisq ;n 3o2 o0r)jhxdh;fl )) have 8 chromosomes. How many chromosomes aroijr.20l nsh3dxfl; q)loh ;)e in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome 1pf:l 1j bvp4si-wg;;dpms ;i pairs occur?

The majority of the genes in the ne2yxm3k *sv )human genome have already been mapped, meaning the exact loca)x kvs2nye* 3mtions 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 linkkzzhwj e6xus ( c9fs--**hrt9 ed genes?

  The diagram shows a kar 9tdxenb82jk:16 baag6hvctg9 ( u /+9z aixpxyogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a 9+a9x g8kb 6/ t(ena1bxu:jv az9 x26ihcgdpt pair of autosomes?

  Mendel observed that there are two possible variations of flower col;bgi7st3h k cmb55z m+our in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1. Whhc57kgbtbi+; 5 3zsmmat were the genotypes of the parents?

  The graph shows the frequency of birth weight of children bogipj16,49n m; xohzw orn in London in 1991; 6ip,ng4womj9zh o1x.

  Which of these traits is an example of continuous va;gdrn 4.imj z7riation?

  Which row correctly describes diploid and hoa gt0.,mrkr )aploid cells in humans?

  The following table shows the diploid chromosome number of a range of se/ k16 ;6atawe/nkgpvpecies.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive gi7r q4( 8mkmyhn v*f0ohj2t 1allele (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 t:zk ksz wm5r;/ q,b(xuype A had a child with blood type O. What are the :xqbs z kukmwz;r /(5,possible genotypes of the biological father?

  Which row shows the correctlar )/s:iv w4yru7ax, annotation of the alleles for blood groups?

  Which of these statements are true forr u8f(4c7 b *qnrxm6aw:0qmiu 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 anabowi,b+t.bcbwl4n /4(v-e/ja k 9hn y emia and the spread of malaria across the continent of Africiy4+b bbhn,en9j4l/. /o(kbww at cv-a.


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 ab81qqj 0+jcg1-gpz leiw/r3 u number of genes. Brown colour (B) is dominant to sandy colour (b) lgj8qw-egr p0uj+1q b/iz 3c1and 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 unlin6hl)ckve r le/1 zx6;hked genes.

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

Sickle cell anaemia is cause 1h.h3)vyuzz 63dr; iiswu4gwd 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 that is h5w n9p zy,v/epomozygous for brown, z e9 5/nppwv,ylong hair 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,aag*9xh v2 +kycq s6t-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short sahsy 9,vtq x62 *cg+kaeeds (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 hpe g5v 1m-x 4qwpz.kp5air (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-squa51g4wp5m. v z-xkqp pered 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 pedigree chartlmkd5 j,a tp9:la92 bf belold9a 9: m2lfpak jtb,5w?

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

  Which of these statements aa-( zet 1mi(1zu;csl+l ,gywm bout genetic 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 normal distrk. wz40t kcpmr1 kfrr- h(tk)3ibution.

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 t+6bxma e69 qc bo,lu,nhe pedigree chart is X-linked recessive and not aue blcu6oqna,m9,+ b x6tosomal recessive?

  Different species of living organisms have di ep*4t 2(chukzfferent numbers of genes characteristic to them. T(2*huc pk 4ztehe table shows 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 characteristic62 ixw*xkg:2f ge3tzds of pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of thesze: dx6i*fxw2g kg23te statements was correct?

  A biological male with hemophilia and a biological female witho 31-b sdkpo)z6e-pulub-nrb * ut hemophilia have a daughter without hemophilia. What are the posssb1n-krpdobu -)bz6el* u-3p ible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants fq0r(bcdr90u (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 09rd( ucq r0fb0.05 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 Ae n9wm-lfq5m 3 and blood type B can have a child with blq9w - 3nmem5flood type O.

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

3.Explain the role of inheritance in genetic diseases.