A man and a woman have a daughter and a2x eqco sxx2gx .v/58a son. Their daughter has normal vision, butxesa2x8 52. xq/ oxcgv their son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomeseg;70 ltn uod bhyh7xl j+3;y/ of a somatic cell in a human male?

  There are two alleles for flowehqi:/; kt)mg5dow bt /r colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white)hotmqwg;bi k5/ td /: and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correctrn1mromz;c4iieul 2 39zyb xt.x,:/ d definition?

  Which of these statements is ai.edpm6lrj5jj -r* j p6f/e2 g correct definition for a gene?

  The diagram shows a pair of ha 2jt4lxidlxmqejqb729vh4s 3 81 gf9omologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific 4zjs woz:ahkgm vv*4g9b12 s(trait, were crossed in an experiment. Which 4:kg4zg(1v*w9 a2s hzv mboj srow shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a banded pat74q fndolr64ntern. The non-agouti allele causes hairs to be a singl7no4f4rq l n6de 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 seezy1 ,5mvz lra8(ysxb.d shape in individual pea plants was either round or wrinkled. The results of an experimenzab .5yrm,(xv1 l s8yztal 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 chromosome 63k :*/ zmjg2qbgquo4a* hymps. How many chromosomes are in a fertilised oocyte of a qg6 jk3zp/ mhba o4:m*2qy* ugfruit fly?

  When does the random 8xjjd3 ( * 1lhcchmbv9orientation of homologous chromosome pairs occur?

The majority of the gmap :rp): gf5oenes in the human genome have already been mapped, meaning the exact locmfp 5::orga)pations 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 x8 *0+;liobdw3gg9 ss 6kk,gsznke y) of linked genes?

  The diagram shows a karyogram of a br( qqw1iqni d3 +ev/v1ct.0d pxown male rat (Rattus norvegicus). Which arrow is pointingec/ 1pdq3wvnvxi(0d+qt q .1i to a pair of autosomes?

  Mendel observed that there are two possible variations of flower coloursc ly)j )+rs5 +g.6xv casajz) 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+)xg .c rzvy5+sac6jj las))s genotypes of the parents?

  The graph shows the frequency of birth weighmfqj:h.ek x1c 8uyqvy011jn) t of children born in London in 1991.nv 1. fx)khj1c:ey0jmyqu 1q8

  Which of these traits is an example of contina(ln c y(jy5 5fun.r4duous variation?

  Which row correctly describes iekpq3j 9g7-. n v3xgzdiploid and haploid cells in humans?

  The following table shows the diploid chromopfgh.h.px2zas2c5kde mp a 67gj6v( 8some number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive +8w 9r.bw3ymu ,x9bdl8 xzdavallele (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 childn rhn rbg9b m7(xdgxa4cp8xe0(/kjbk- .0i0d with blood type O. What are the possiblek.9h r(/ejd 7bpxgi 0-agnmkx (x00db4cbr8n genotypes of the biological father?

  Which row shows the correct annotationgl6xet1wg +h- 2-kh0qcnydlsw2.peg 1; wx .t of the alleles for blood groups?

  Which of these statements are true for allele6jhk*t .1jxb3 8hsk:o yijhd *s?
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 sickf+1,loh9gnsr c 1wqf 7le cell anaemia and the spread of malaria across th hl cqf9+w 1r71gfson,e continent 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 przvi1j/ku 6k1 mkkjs8qk czz 232ewalskii), fur colour is determined by a number of genes. Browk631skc2kj/j vqku2zimk z 18 n 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 unlinked- fjrdfzyt,n/29u;lzmxd2 w sk.5w+ d genes.

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

Sickle cell anaemia is caused by the allele Hbq5*-vy 0(gzwgjg- siz$^S$ . 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 bet5 *bzj9z9fceo2j. yp eween a male cat that is homozygous for brown, long hair an.*2jz9jfb zypoe9ce5 d a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele fo* +bk l,ewr n9()d vl/qrcuw7wr diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for lwk+ v)(9,dl b7ecwqru /nwl *rong 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 short-1 5y,yw2cy8 kg ymbpp hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous ly2p5gbm yw1c ,y8-pky ong, 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 inheritance of the condition shown in lj6qxkl6,ew.b07a il the pedigree chart be liw b0lq6x,a.k76 ljelow?

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

  Which of these statements about genetic disorders ucwfr u9l 8a6.ym6w 3yis/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 normayjqsy)+):: bzh2mzk m l 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 sh5.j5 2p+gq sbjixt-dfown in the pedigree chart is X-linked recessive and not autosomal rec25-gqtd+fp s i5bx.j jessive?

  Different species of living orgg,jx.dd( 9j3 d.zbvypanisms have different numbers of genes characteristic to them. The table shows the estimapd3(vzb d9y. jxd ,.jgted 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 plaxo9do 1xvq2hq4bbnk;t53( o cnts, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, whic3o4bkox;2x nc h9 dq1 votq(b5h of these statements was correct?

  A biological male with hemophilia and a biological female without hemophilia ha0f4tlds tvgb)f4x/2 m ve a daumfb2l)g 4s0 dvx4/t ftghter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was c bfm. g5ysj*:sah 2pvp+lze53arried out between 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 0.05 significance level was 7.82. The calculated value for the chi-squared test was 10.05; what does this indicate?ah:gmls2 yz+ vbps3*5e. p5 fj

1.Explain how parents with blood t+-j fe7jezlc5cw/ 2+bp*eb/tz t xvp7ype A and blood type B can have a child with blood type t x e2 +cf epz*/jbtc7/b-wj5+7zvpelO.

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

3.Explain the role of inheritance in genetic diseases.