A man and a woman have a daughter and a son. Their daughter has normal vij tqv cx(bez4;o. 10zhsion, but their son is colourblind. Which one of these genotypes c zxct0; 1jo(zh4b.evq ould be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a zf fwr(+ 0;eyvhuman male?

  There are two alleles for f1v 1bkguq5 wb0lower colour in snapdragons. However, the result of a cross between two heterozygou g1bwv1uk q0b5s 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 x )n(fy h 0b4r/ugun4hto the correct definition?

  Which of these statements is a e 41nhbgs 1k; 7jbstq 3zm;)l5 mspy,fcorrect definition for a gene?

  The diagram shows a pair of homologouvyd:p3kmubmf :2b+2ms chromosomes.

How many loci are shown?

  Two individuals, heter)8uhx, c o0wlxzvm; gn4 gcb(4ozygous for a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulti4l8b0cn(u cm ;hwx o)gg,z4vxng from this cross?

  In some animals, the t7nw/ hmwna1(agouti allele causes individual hairs to have a banded pattern. The non-agouti allele ca/ htnw7nw( 1mauses 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 individual pea plants was either round o6jp0,hmo-w8 uvf 1 ssxr wrinkled. The results of an experimental cross yielded 315 offspring with round seeds a8 su 0m-w6h1oxv pjsf,nd 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 chr 1ormh3r(vo9 yomosomes. How many chromosomes are in 9oh1 r(om3yvra fertilised oocyte of a fruit fly?

  When does the random orientatioxgy ;e00w bk*kn of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped, meanin-w5o8tufvtnn2nfah 2,iq ; 2gg the exact locwth82,-ai fn; 25tqufgnon2 v ations 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 derc71,tk n q :w8jnzwu+finition of linked genes?

  The diagram shows a kaa 9cx r06l2656hp.t (umhkxc y.o(t bvgia4e tryogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosomes?6.k(69i2 0v arx cb(geuc hx5olta.6tp y4hmt

  Mendel observed that there are two possible variations of flymo5x,7 7jtv)yr cr4gower colour in pea plants, purple and white. After a geneti jx7) rtrg5,oyyc74v mc 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 frdm3,l 6l lmpi6equency of birth weight of children born in London in 1991. ,m ld6i6pl3m l

  Which of these traits is an example of continuous variation2jfnylvfv r :v6o(2kk7 9tyh: ?

  Which row correctly describes diploid and hapay5 a9r zqp:(kloid cells in humans?

  The following table s;bhjod6r ,ooq 0q6(nb+rm7 s fhows the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is causid l+zpd(v s(9ed 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 bloocyy,t1v i5yyu* xjp/8uu9s 1uy /+st ud type O. What are the possible genotypes of the biological fa ys /puy1uuc sty1 /9iu+ ,yxytu5jv*8ther?

  Which row shows the correct annotation of the alleles for bloodevy0s5iaz n )yg1-9fg groups?

  Which of these statements are true for allele5pcq* lw)wz*vb7 ubd+ 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 incivocp1yy*.e v 3dence of sickle cell anaemia and the spread of malaria across tc*vypo13y .v ehe 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 przewalski32jm2*qlu f)wl0mazdi), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (tw*qumdl wa 0lf2m32j )zo 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 genesqmmp *d,)dx/6c- wh uk.

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

Sickle cell anaemia is caused by the allp.e p 9 hsxg 4187smsf;wp4gynele 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 hom )1l*he svshx1ozygous for brown, long hair and a female sx*ve1 h1)l hscat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diar0d-q*3rs5 x 8lxeseu mond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant overle5 0 * rx3qdsus8ex-r 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), lopbst af e;b8.5/-q mgxng hair (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-hair t5a;e.xsqbf -p/8bm ged 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 ff yhna1k4jw-lwu +/akdy:59condition shown in the pedigree chartk u:5hyf19w jyaal - nfwkd/4+ below?

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

  Which of these statementpd9-r 8ss;9 m bd2 pzfyw3hd.as about 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 synh, 89pro0 8ds;kpbphow 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 g.f ob(dhfa5 6of the disorder shown in the pedigree chart is X-linked recessive and not autosomal reg.fbaohd(5 f6cessive?

  Different species of living organisms have different numbers of genexc7 je y3qc.8as characteristic3e 8c7yaj .qxc to them. The 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 characteristics of pea plants, including flower colour. Ifz,ox+h0e2(hqxw+wb4xd p(rl s u2yp 0 the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?xzdpl0owpb +hur2e,+wq4x2 y x(0 sh(

  A biological male with hemophilia and a biological female without hemop0clo)4m ujh e2hilia have a daughter without hemophilia. What are the lc 0e)juo4m 2hpossible genotypes of the daughter?

  A dihybrid cross was carried out between two sunfloer-*z7 n6- i wf+fxlutwer 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 fwl unt+ff6rx7z* -ei-or the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A and blood tmz 20erz,(kgu ype B can have a child with blood type O.e0uzz rk,gm2 (

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

3.Explain the role of inheritance in genetic diseases.