A man and a woman have a daughter and a son. Their daughter has normal visiw2j)u3mrh i i/on, but their son is colourblind. Which one of thes3jii) / hwru2me genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes ofdzn-i+3is fbeb8qj0o,nc v- : a somatic cell in a human male?

  There are two alleles for flower c1f0mm*-* rljm+ ofp zholour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, whit*j l1 0-zmpm fr*f+mohe and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct defpffma6 gx 5xm+ait ds )j27l*8t, xa4uinition?

  Which of these statements is a correct defini5m zk/4t*k5 o st4)zjd mmvt,ntion for a gene?

  The diagram shows a pair of homologous chromosomes.7btpk 4* q+brq

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in agjv5djz +f r;(n experiment. Which row sho5gf+d jrjz(; vws the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes ii 01cbmar: .c5ksxkj/ ndividual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozs ric:ax /c.kk10 j5mbygous 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 ei3s4gf;ew0u a73dq mueor* -nlther round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled f-uolg arm*0wuns3ed3e74 q; seeds.

Which row in the table below states the most likely genotypes of the parents?

  Neurons of the fruit fly (Drosophila melanogaster) have 8 chromomvyz d/5a*it+somes. How many chromosomes are in a fertilised oocyte of a fruit fav m*dt +y/5zily?

  When does the random orientation of homolog )b1frt:,pia cous chromosome pairs occur?

The majority of the genes in the human genome have alrza5 2zfxghhz6o d37 +peady been mapped, meaning the exact locations of the genes on chromosomes are known. The d7z+3hzxgad zh 6f 5p2oiagram 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 defi h,e nvyo5exusu+jf2 h9(:m k5nition of linked genes?

  The diagram shows a karyogram of a brown maldxa4t 1c 3fdb83g /yoze rat (Rattus norvegicus). Which arrow is pointing to a pair of afz3a b38x 4/cy1dtdo gutosomes?

  Mendel observed that there are two possible variations of flbi d-3us6g y/vde 1lt-ower colour in pea plants, purple and white. After tg-36blys ui1d/- evda 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 fr.fcba -8e30z r;n/pdbh(bzr9 7b zyagt5r 1ynequency of birth weight of children born in London in 1991. yeb9 5d r/7fczb h -z;.anrtyzanb830rb(1 pg

  Which of these traits i.j hupmb1u8 n,s an example of continuous variation?

  Which row correctly describes diploid and w9) :2i g joxf9vlpu4ghaploid cells in humans?

  The following table s2ld*41d c0o0uw jzqhohows the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a muqv k t2x(*9flh-k,g 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* m qo1fagw6o4 fcx4r1 are the possible genotypes of the orx*gq f 1wmc6a1 o44fbiological father?

  Which row shows the correct annotation of the alleles f s4;0wf* aq9youjgi7d 83ahhzor blood groups?

  Which of these statements are true for alleles; os6b+ kuh9n,5 omisj?
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 spre ezw p4em +c6d*.wrekt b8x:(oad of malaria across the continen8wc * eekm4 twe+b6:d x(pr.ozt 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 de/e-qd p6 4w/ shpmavd)y op 4b-30xmxstermined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to d4dmhpx0sv-eaxq/3s6- p p omw y/4)bone 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 0th3 uagqe04and unlinked genes.

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

Sickle cell anaemia is caa n38:lbicsg 2/1wgyv used 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 that is homozygous s n4o hv/2f48zn1h,dpuaox7j for brown, long h ods2ao71,/4zp njnh4 xu8fh vair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allelgci. t)8q7niym8 zjk3e for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominaigz 8y7knc.im3 q)tj8 nt 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) is dominant to short hair (ly ,*wow7qv- ql), and curly hai,wwoyqlq v*7- r (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 coe 7 m53swm 4jbm-h*u*pb5yfppndition shown in the pedigree chart below? epfm55*pmw puj b- ms47 3yh*b

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

  Which of these statements aboump:v59nweg7z t c/(ti t 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 norm9.5bf+ c 1u-+aw )ckucxednxaal 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 pedigr 6)ve ;har+ssaee chart is X-linked recessive and avsr6a) e+;shnot autosomal recessive?

  Different species of living organisms have different numbers of go)sn k;z;jlvncc xyy:6m( e9 -enes characteristic to them. The table shows the estimated o c x;ysm)cklz;-e9(y njv6n: 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 o lyzw; hoky 0bh;oln;l o;fad3c9 +.5jf 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, w;z;0;3+kwh;o5c y bf9l o.hlyndlao jhich of these statements was correct?

  A biological male with hemophilia and a biol: (fdm:brw;;rlzg2 paogical female without hemophilia have a daughter without hemophilia. What are them;fl a rb:2zp:(d; wgr possible genotypes of the daughter?

  A dihybrid cross was carried out bet+y,ch ix 4r/rf (i4mepween two sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical valum pr(ci+eh4fxi yr /4,e 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 type B can ha c2v el 8ja9qnl2)2tp5gptlp:ve a child with bl)n:jplg52 2eptl 8q tc p9a2vlood type O.

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

3.Explain the role of inheritance in genetic diseases.