A man and a woman have a daughter and a son. Their daughter has normal vision, tr.e:wj) igx+) cl ap0 fjj ej(s7k74zbut their son is colourblind. Which one of these genotypes cof)7 +(zal. kejj)4xjer0gjw: s7 ciptuld be correct for the biological mother?

  Which diagram shows the sf3 gf7fk/r )wxk 8;bhwai88uc g3gv, rex chromosomes of a somatic cell in a human male?

  There are two alleles for flower hbwy9) e((;9c zmg,jhh k4e yycolour in snapdragons. However, the result of a cross between two heterozygous plants yielded offweky h y b; (zj(h9mc9hey4)g,spring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matcpla)+bn/ zragwl)15 o hed to the correct definition?

  Which of these statements is a correcv3p4go95swlc(1b2 -y-kxup q2i ap jqt definition for a gene?

  The diagram shows a pair of hop a9qfu0t0gdf t*p -h(mologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were cross y3bs(2o(23 pninlh uq d+.juced in an experiment. Which 3ynsjcu2pnqud.+b l( (h i 3o2row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele ) zabpl. ab16gcauses individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous hav balza)6 g.p1be 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 wasjxbr 3t( xy;.g either round or wrinklgx3. yrt(j;xbed. 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 m(r j.v2njdroa35qh hj1z.yli*h8fu.elanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte ofr. jlo 5j8jvndh(2qyhz 1h *i.rua3.f a fruit fly?

  When does the random orientation of homologous chromosome pairs occur?s(c kz1p3uoacv972m(wrjkh v i3,5gmswku :)

The majority of the genes ilpp(g f5/fbm ,n the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a , fbpplm(/g5fhomologous 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 linked gen8sr9-z -xg wldes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Whicxk(vq5q0a qi, h arrow is pointing to a pqak5 0qv(ix, qair of autosomes?

  Mendel observed that there are two possible variatiolkyb)+ :wp4ciyy ;7wnns of flower colour in pea plants, purple and whitebcnww:ly)4yi; ky +p7. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth wen/jntkhs s (2qvs*7 (eight of children born in London in 1991. nkss jet*(v/ sq 7h(n2

  Which of these traits is an example of continuousrv/)vvtm6 rj/0kv hzgx4 /in( variation?

  Which row correctly describes diploid and haploid cells in humans?i3q1.dcm69cvwzq8 2vm, kn r y

  The following table shows the diploid chromosome number of a range ofp z m 1f,n5,6;iza1xcv n-q1.exow vbm species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele ghj( +d1zb i*m(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 hadgi21 bcr p fn15unbv0c*/e5lq a child with blood type O. What are the possible genoty12cf0g1 cu/qienlrb5v5p*bn pes of the biological father?

  Which row shows the correct annotationrwk d1e;bz i3gzay1 y6i -.d(r of the alleles for blood groups?

  Which of these statements are true for allelor9 lw3x: .pydes?
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 tgzr)wsok*+at/ h ;d ok1wok11he spread of malaria across the continent of Aw skz ;r1)a*o otk1wdk1h/og+ frica.


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 przewaorf2h vgz5qkjl:7ii6 jc,y8 ohgb*85lskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sanif2jgo8okb5, z:7qgci v *hjyr68hl5 dy 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 linkj f4+ei+ -a k)ds0bcqped and unlinked genes.

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

Sickle cell anaemia g6cqko3/ x:7xwx-ae 0(b( zm9khnx tkis caused 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 malbjkzf* (n d*x+p) 2t6gix(sgk e cat that is homozygous for brown, long hair and a female ca+ks(j p(n xkgf*2dtgzb x* 6)it that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele fs;my+tl g)9ngor diamond-shaped seeds (D) is dominant over oval-shapeg tl9gym)+n;s d seeds (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) )nqvazkw+ c: fj+3b1x os;1meis dominant to short hair (l), and curly hair (C) is dominan f; s+ncvm:ekzxo11qj 3+a)bwt 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 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 i 3-l vzr,uk +yu.xnuy6nheritance of the condition shown in the pedigree chart below? r3ly u+,-z u ukn6yx.v

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

  Which of these statements about u zld)rksf.t m:;9:-bl saokf.pxg18 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 distribution(j6nam;i 2)hm 9zgr os.

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.y j cgn h.2q*t sk4ggovdoj/i05+p nu.va3 y( shown in the pedigree chart is kjgo 0vp5gn*j+.icvo3n. .h (y4 atugq/y 2ds X-linked recessive and not autosomal recessive?

  Different species of livingdbz:+f ).: fxhxmj*u5u-u idy organisms have different numbers of genes characteristic to them. The ta+mxufj5biu)zfx *dh d:.u- :yble 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 characteristics ofqr72i vcdy:ct .ex: l92sh-ow 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 these statem9.o clsvd2 cxwt2y-q ri7h::eents was correct?

  A biological male with hemophilia and a biological female without hcc0 f5(bxjec 5emophilia have a daughter without hemophilia. What are the possible genotypes of the daughterf(5xc jce0cb5 ?

  A dihybrid cross was carried out between two sunflower)v wqzjxknnp ,e t*,va+cu*8. plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical v qcw *+)8nvxaktev,jnpu.,*zalue 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 9ih dc3g*3tg *ujdl3cblood type A and blood type B can have a child with bl c*tidj33h*uc39gdlgood type O.

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

3.Explain the role of inheritance in genetic diseases.