A man and a woman have a dab .*+n yfyg*mg 7gqwm2ughter and a son. Their daughter has normal vision, but their son is colourblind. Which one of wq*by2gg m*+ ynfg.m7these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a humfaev(g r)581yw,io 3gon. xu+9 mhp t7j-he mkan male?

  There are two alleles for flower colour in snapdragons. However, t67byj 0a/q txgn;t bj,he result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation f,bx/anj6qyg; tjb7 0 tor this observation?

  Which keyword is matchemqzjl) vv56x; w8a,s ed to the correct definition?

  Which of these statements is a correct d:k)s c4g6 t boy6g.w)r nd*snvefinition for a gene?

  The diagram shows a pair of homologou ) 7ax wm9ay5y.4 kfcuc0a(llhs chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in a7+t pl () uk tr)6mq,,suityttn experiment. Which row shows the expected phenotypic ratios of the offspring resulti(utuks,)r m+qt l,y6t) t7tipng from this cross?

  In some animals, the agouti allele causes individual hairs to havefb w406wg. )m jmvf.ziko; .mk a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairso40.6f.m;bk fvi m)gkm. wwzj 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 qq 2)jyi0 4aox2ivti: round or wrinkled. The results of an experimental cross yxaqjq4i2i i0o t :v2y)ielded 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 8mz1d 3:qkw*5 zcceqr8 chromosomes. How many chromosomes are in a fcwq qr58kzzd1 m3ec:*ertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosomh(d0x+b i1b6 qqj:oi5f ia,k re pairs occur?

The majority of the genes in the human genomel,;/,jdr4 1jrp(j pryzp2uxe have already been mapped, meaning the exact locations of the genes on chromosom/zlj(rxjrr p;eupj 1p2, dy ,4es 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 definitioqtz3c v (y6fxnfbs+szl :7n45n of linked genes?

  The diagram shows a karxi3k g vi,osfk 9+su4d,4:y0b kothd/yogram of a brown male rat (Rattus norvegicus). Which arrow is podof,3 ik 4hssuvbg yi 9:/xtk,o04+k dinting to a pair of autosomes?

  Mendel observed that there are two possible variations o 6c:gm(;vnn.* n dyvyhf 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. What were the genotypes of the paremy g*; y:vd.n(nhnv6cnts?

  The graph shows the nl:f/ glp84apfrequency of birth weight of children born in London in 1991. 4 8pn/l:plgaf

  Which of these traits is nh88p z6ny7q han example of continuous variation?

  Which row correctly describes diploizmd;c8*g0ss ,mxxp 0bptb 5u*d and haploid cells in humans?

  The following table shows the diploid chromosome number o*32bj gt+3v:+ d/ n3 achswqy,sr wtdjf a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recesslw,,sywe+1ll1b x jp1ive 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 b.:dq1iv:ayq2q.h4 w+l8p di; om wtbllood type A had a child with blood type O. What are the possible genotypes of thmplv :qa :.woib8;q42.tid dlyhw 1q+e biological father?

  Which row shows the corril6lfh13s . ccect annotation of the alleles for blood groups?

  Which of these statements are true fdfs n6.(v oa95c;hb odor 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 h7kg*dhgw)- fgy 10zb sickle cell anaemia and the spread of malaria acrog1zk dw-)bghhf g* y07ss 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 vej zv6/g0j6i0 3nc,h7e prkinumber of genes. Brown colournhripv0k0jg, i7e z/ ev3c6j6 (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 r- ffsngcg- y:pd5 04vand unlinked genes.

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

Sickle cell anaemia is c v7af:vsmzkd (y687-w1qemtva )v/ lgaused 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 shog 7bm0/ ,tnt,mxle6vxws a cross between a male cat that is homozygous for brown, long hair and mtx,tx /g6mbn,7e0 vl a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officin x 23nqsfwndb+s48 gt60o.cixale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant ovn0qdt6g2w fb+isxc . 348x nsoer 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 bc)sh,si s 0eu s 9.0oo8c u,b5a0riudto short hair (l), and curu0bah o8)si csd9ure s0b, c0u5. ,soily 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 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 co2 hireay3id; 0ndition shown in the pedigree chart beliyhr0 i e3a;d2ow?

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

  Which of these statements about genetiho 3 tgy3d3fe0fmiz/-c 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 nors*xn ezeeh rf:*wgmeha2 0l7v+ cc9ee) 9w )+umal 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 shown in the pedigree chart i2ajv4mu --hn2avm h 2us X-linked rec42-2 a nu2muvhm h-vajessive and not autosomal recessive?

  Different species of living organisms have 1. l(otsbw2u x-n zg13nvsyn1different numbers of genes characteristic to them. The table shows the estimated number of genes forsns3txu n1v(wn21lgz.1yo- b 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 flowe so,lrv9/h ip16g-nw hr colour. If the pea plants Mendel was studying can only be white or purple and follg,9-si o1whlr/ pv6 hnow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological femaiktg,v.v8z u k9v19u y*l s7fjle without hemophilia have a daughter without hev tl8uy v9v9kkgif71*zj,.usmophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (og:.eco;2 drxHelianthus 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 indicoo dceg x;r:2.ate?

1.Explain how parents with blood typmf6m+,evt7tw tc *t*ke A and blood type B can have a child with blood typewk6*mt f*ect mv +7t,t O.

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

3.Explain the role of inheritance in genetic diseases.