A man and a woman have a daughter and a son. Their daughter hak2w *lalp-6kk c 7ji*vs normal vision, but their son is colourblind. Which one of these genotypes could be correct lkv6lk 7*pij2 *-wckafor the biological mother?

  Which diagram shows the sex c ne;b((l0yb ep4-dqzm hromosomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdragon 2. 84vkqr8l6knzd*x /8tikxf kne-e es. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white 2vfkx4 q8ke 8*dne t/k.x86lknzi re- and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct d uxf9in/ *jr /bei8umc,0+ icsefinition?

  Which of these statements ihs:e +cv*kzcy2 nnhn1d51ju oe l0+y:s a correct definition for a gene?

  The diagram shows a pair of homolo:amkfci* .6k;y bwc/r l r:qp.gous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an experimekvmvh)+rw idf7kb)va p .u*(: nt. Which row shows the expected phenotypi v:wpu)i(.7r+f )dv a*bkmkvh c ratios of the offspring resulting from this cross?

  In some animals, the a 6x1ar/iph. zqgouti allele causes individual hairs to have a banded pattern. The norx6i/1qh p.a zn-agouti 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 individual pea planxx3c48 lt1axgts was either round or wrinkled. The results of a3x8a clg xx4t1n 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 melanogaster) have 8 chro62w7 8ipgay) +d.6bif: sogm/rx lbuamosomes. How many chromosomes are in a fertilised oocyte of a f8bl7 igir:.aa m6yfdou+xw/s )g p2b6ruit fly?

  When does the random orientation of homologous chromosome pairs occukajyaktk+ *3/u0s z1zv1 wed5r?

The majority of the genes in the human genome havase*o. iug7:ae already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of7aso:. g a*uie 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 defin4g-g ;x+,bjacph6c w vition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicuxep zx m:oi//.s). Which arrow is poii /:.x/emxzpo nting to a pair of autosomes?

  Mendel observed that there are two possible varim b*a 2w v:wpg,rt(5afations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1. Whawv(b2,gwpra f*ma: t5t were the genotypes of the parents?

  The graph shows the frequency of birth wed(n cq/m:int0 ight of children born in London in 1991. cinn0qmt /( :d

  Which of these traits is an exampg shtfi* vyitz+-; 1h(le of continuous variation?

  Which row correctly describes diploid and haploid29v *e1f 0k 2ls0v/p1ujrzqlm7kpw mp cells in humans?

  The following table sho0xeiw- .kl6mi1odv u z;e 822t*qxs xews the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is cazjlmp8k wz 6i 9::ahm.3czo( vused 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 blood type O. What are th)qrmp7x yzs,n)eo f( +e possible ge +pn,z)fq(s)7x om ryenotypes of the biological father?

  Which row shows the correct annotation of the allt02, poe4fnmx eles for blood groups?

  Which of these statements are true for axewu5ec7gam/h +h4 ,jlleles?
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 anae-hs1x r isy5-emia and the spread of malaria across the rh - sis1xe-y5continent 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 dete 5e-/ nyu/im;clm(kndrmined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour -/ilmeukny5/(mdn; c(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 7y+ k+poyc1mjlinked and unlinked genes.

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

Sickle cell anaemia is causedkhoh0p/ llf+y2dfm m(l7m8 /qu2s4 dq 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 male9xswy.6 4m 3igely* ym cat that is homozygous for brown, long hair and a female cat that has black, short hair 6.4xy9ml* igwyys me3.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-sha81envn5n vwx r1fak1 6m2ud (fped seeds (D) is dominant over oval-re652vkv(nua f1 1mf1 n8w xdnshaped 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 p34x(k mzq02d yiwwg. uorcellus), long 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-haired guinea pigs and a chi-squared test (χ2) was camz(y30u.q 4wkgd w2i xrried 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 c0mp;dz; tl8 kkondition shown in the pedigree chart belok8z kptd;0;lm w?

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

  Which of these statements about7i x; aece0rrq25ct9*v)r )d ojdsu7q 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 distrstn rvkprzd yp,e86p(* g)0l2m+ d9dy ibution.

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 disor7f0tm 09c f:iec+eyx8po s n*lflk8m( der shown in the pedigree chart is X-linked recessive and not autosomal rece +0yfccmo07i*n9 fl:skx(ee ltm 8p8fssive?

  Different species of livj s3dzm) e zw(s;0rks-ing organisms have different numbers of genes characteristic to 3ssdk-wjzes)0r;m(z 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 characteripjyj eo:fl .6/uo7 zd)stics of pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and foy:op/7zelfu odj6j) . llow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a bb b.r5k)4eflf,fdon+ iological female without hemophilia have a daughter without hemophilia. What are the poso n)b4 r,.lf5dkbf+e fsible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (6wc ):h -,j/nsi vwp)2opd0mfll j bn(Helianthus annuus) to see if the genes for seed number andbs jfhw0 mp/ nw2oc)j- n,)(:6idvpll 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?

1.Explain how parents with blood type A and blood t fw:qe5 2 kt)vz8t,gpdype B can have a child with b8zw ge: 52kp t,qfd)tvlood type O.

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

3.Explain the role of inheritance in genetic diseases.