A man and a woman have a daughter and a son. Their daughter has normal vision, bl: b+ bxa3pt.6mykfct( 6uan :ut their son is colourblind. Which one of these genotypes coul t:nkx6ytb ca bf(6:a.p3uml+d be correct for the biological mother?

  Which diagram shows the sex chromosomes of a*m*z, u: urfne somatic cell in a human male?

  There are two allele 0 ;;)bgj) e3mfk2yunpyoll1xs q218p q,n cays for flower colour in snapdragons. However, the result of a cross between two heterozygous play2)n,o2jxg m1c;p)ylk0l sq a1e3;bqy fn 8punts 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 the corre2eghb k(s(v/dct definition?

  Which of these statements is a correct definition fbfi4yg,x f r6(or a gene?

  The diagram shows a pair of homologous chromou9x1 /( (ey fj-fujkwasomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, wer zyev)l8) h1ure crossed in an experiment. Which row shows the expected phenotypic ratios oflye1 ur)8)vzh the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a ekc9z kf)su4j*8s/fri4vb4/i7 7 v/jbqws t r banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous hav vj87susv4s)/* ez/ k4/4ji97bf i rbwfqkrtce 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 ruihsh wg2s3 /9ie(wmn4 v3+gor wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring wiv39 +gisimsg2(nhrue w h3w /4th 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 chromosome7bpu jhepnms( a- 55j-s. How many chromosomes are in a fertilisn m 5u(-ja-h5jps7b eped oocyte of a fruit fly?

  When does the random orientation of homolog 2sxz q7sqa.a1ous chromosome pairs occur?

The majority of the genes in the humloeus(5bi04l /uc, ssan genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below showu4 sse lsc5 (loubi0,/s 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 defincfpvc7q/9j6 vition of linked genes?

  The diagram shows a karyogram ofcam)a s m )88frjfu2lkd4b8u 2 a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of au)84 8sfl 2akm8cu2dfj mbaru)tosomes?

  Mendel observed that there are twoes f0aj+*l9a9:zwsu x possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowf: wj a0e +xssz9a*9luers is 1:1. What were the genotypes of the parents?

  The graph shows the freq4z;dc1:azwbl6feq,:rij 4o q0 q,a05tff jfe uency of birth weight of children born in London in 1991.4; ,j:z4fo ef0qa c,6a teif qz1 5wlqj:0brdf

  Which of these traits is an exap 0u(qq mto-93mu8 xuzmple of continuous variation?

  Which row correctly describes diploid and haploid cells in ykf3ojc.32o zn 9 g 6qmf55nhwhumans?

  The following table shows the diploid chromosome number of -- qhcyv5 fonae(q.5 dnmc7d2a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caus( h p6gfxrk6r5ed 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 a child with bl.eoq2,wut*9 vkt y1s hy ie)s/ood type O. What are the possible genotypes of the biols1oy9w2 s kh it /v*ee).q,tyuogical father?

  Which row shows the correct ann1d x2)tyjwrc8otation of the alleles for blood groups?

  Which of these statements are dm5;x 1 ths,y 5ef,*xgp ai4thtrue 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 sickle cell anaemia and the stlk g1g)w)v-ypread of malaria acros t))gvl- wy1kgs the 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 przewalskii), fur colour is determined by a number ofr/n ml.asb55q4*usd74 1 gz ndfj jrh* genes. Brown colour (B)7a *1grnr s/uq5fsb4.jdmzj 5*h nl4d 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 genes. mt ;y 82uul,hseh 72 nxkq1zi+

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

Sickle cell anaemia is caus u 14lyry-+daded 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 thgequ c0 ,pia sjn36q7c.0q8alat is homozygous for brown, longql7,cai6q jp.a0 8sgqu n 03ec hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele fi/f:f.ix *iu5 zu4g/s sx4twror diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short seeds (l). u.uxsfw/ rt:ii*gxi f/z5 s44

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 h7o(pv8;p +wyqt j cna/ *6btakair (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) was carried out on the ofky*b /6ctpw;tn+ap o(8 ajq7vfspring.



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 copisgb* ym cn;yif(ko)f;.e05b luwh;j3 d. 8mndition shown in the pedigree chart below;;n38iyh;sj bwumop5mb i.y e c) lfg0*dfk.(?

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

  Which of these statements about genetic disorders is/are cjgem4 7- i2k ai5vosv+orrect?

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 distriky2z ujq7 wl05t(,s i,dreb( wbution.

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 disor1+bqtc 7+z cxb,l61v-lxo d ovder shown in the pedigree chart is X-linked rece7 1btvbo +ocx 1c,-q lld6+vxzssive and not autosomal recessive?

  Different species of living organisms have different numbers of genes character -t fbe7h6o.o9jbgn mqc6g a92istic to them. The table shows the estimated number of gencf 6 ob7ogman-9e.6h92qtgbjes 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 colour. Ifxks.:g4 w k(se1tizr 1 the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian gene.(i k4w gs1ts 1kexz:rtics, which of these statements was correct?

  A biological male with hemophilia and a biologihy/:bd pqogulbv 8 -147jrkd+cal female without hemophilia have a daughter without hemophilia. What are the possible genotypes ofbk4o/u-g q pydlhv d7:+j1rb8 the daughter?

  A dihybrid cross was carried out besd3o0of4kf5x 5vumj b20;n uws o1qi l4la3l(tween 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 valuelso(u554 q0v 23 b linsuwd0 1mfoa olk3;x4fj for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with bls 1-rv2(dhcfsood type A and blood type B can have a child with blood type O. dcs2fs1v r-( h

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

3.Explain the role of inheritance in genetic diseases.