A man and a woman have a daughters tszkmctvw;n:kq/eod 16 28g+6 /ydp and a son. Their daughter has normal vision, but their son is colourblind. Which o12cgvd6 kyt/wt:68qemzdkps + osn/ ;ne of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cel6mm+b +ydfx,j3i/(vwlip e. tl in a human male?

  There are two alleles for flower colou(atw:f ki4t n(ga;i (mr in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenoty:4it g(km(if;nwa at(pes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct definit8pk220bvti b nr *zx/nion?

  Which of these statements is a cqq/*erhlh00 zt(i9r wpf eu5 0,- cincorrect definition for a gene?

  The diagram shows a pair of homologous ax3. xhp6)v3k.ym 9nh*xp y bbchromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an expeo ndkovl9yo ;sk8p,wx/l//1 criment. Which row shod,c8/ln/o1y;s/lw v kx9o okpws the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a banded p/hg:x1wdli 7x-k pd+q atteripd-x7+xq hdk w/:l 1gn. The non-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 pol 4h5s5 e0z4sgp4xicea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkle0seho ic 45gsx lz45p4d seeds.

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

  Neurons of the fruit fly (Drosophila melanogaster) have we9 0zt g6(jig bxk(p78 chromosomes. How many chr0pt(ki(xz7e 6gjwb g9omosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homol+r 1b hi1y2rwfogous chromosome pairs occur?

The majority of the genes in the human genome have al1h2 dh6 kg08o,f guscp:zdrh)ready been mapped, meaning the exact locations of the genesc,zh6 hps)2d d1 hgkgr0f uo:8 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 definitioth ,dhghfr.;8 n of linked genes?

  The diagram shows a karyogram of a brown male rat(ybuj 2m)fb2p (Rattus norvegicus). Which arrow is u(bf2mj)ybp 2 pointing to a pair of autosomes?

  Mendel observed that there are two possible variations ob 47brxj/bf hg xedq3u7a-i3;f flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with pur3ah -xir f7bugdbb4qe/3j; 7xple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of children born in London in nu/yxhfy.ad as4y r+ - bnu(7/3e tk,d1991..4 /y-ku by yr(ns3 7dde+xtun,hfaa/

  Which of these traits is an example of continuous varia (5kw67zszrmw tion?

  Which row correctly describes diploid and haploid cells-r 3eyz s6d5(bli, fkb in humans?

  The following table shows the dipj5caz gx-*g*mloid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allef ,f4ut6ctomlhej 554c.1mki +a kn4 zubf.q 2le (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 :hkigz4)*8 rhccnqip gpe;n q( :hhc +3).nhoa child with blood type O. What are the posspi.r4*c)gh)8 (h3qk :p nch;coig q henhn+ z:ible genotypes of the biological father?

  Which row shows the correct annotation of8,1vwp u/hv qao vd5l8 the alleles for blood groups?

  Which of these statements are true for alls0/y22jl5z zyc6m 5hb 3x goikeles?
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 ye2jrfr (.r9,lh s-d pcell anaemia and the spread of malaria across the continent of Africa. ,(pyldr9 s rrh j2.f-e


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 determinedj/ 7)o8ku5zta; lenyr by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to one tone (p);z 7oj5) k8 lytuna/re.


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 unncxow/ )em2di (s8)o b1ecx1o linked genes.

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

Sickle cell anaemia is causonc-md6 gs9jg05i fo ,3c ta3ded 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 holek9(*sh ,6b))tibda . : 0bznrfawdjmozygous for brown, long hair and a female cat thabw),btz rdba.6h idae:lk9 s)j*0( f nt has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped seeds (D) iqnjc:3 yo,r03 -mvx/qry:ih ys dominant over ovq:xqnyh:v 3coryji,- 3r/y0 mal-shaped 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) i7jozslyorww)z *bhg-p87 8dx/4 qrq*s dominant to short hair (l), and curly hair48r- **zp/ o7jlwwzq bs7o 8qgh)dxyr (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 condition shown in the pedigree char 0lu5lwh/vk/htez 7 f6t b huh7 /elkwvz0f5/6ltelow?

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

  Which of these statements about genetiwq 3:n+ fdp rjd16f7xp/6 okjazz:+zbc 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 shoqua,48c5 aqbo w 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 inheritancjk ; ;laufyy-flp 9+03ecb4ece of the disorder shown in the pedigree chart is X-linked recessive and not autosomal e+a9ecjlkf3yycu4 - ;p0bf; lrecessive?

  Different species of living organisms have different numbers of genes mg v +ubaa95g(characteristic to them. The table s(g m5avga9 u+bhows 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 coloure pstb;a )k zq0vpuk i a5qxa5bu2e.v7,+o.:p. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetic: a ..z kpb5uq7koapei2+ )bepu; t5qv as,x0vs, which of these statements was correct?

  A biological male with hemophilia anfoa sn:1m: fg.elt91e 9d bo9nd a biological female without hemophilia have a daughter without hemophilia. W:1 oo sead.t:eg9l1bn9 mn9f fhat are the possible genotypes of the daughter?

  A dihybrid cross was carrielh5h i3nj o p18;eo;ahd out between two sunflower 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 leveh;8oh;nhp5jl1 i oa3 el 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 have a child with w by:5+gtud70spdu; k blood s:w;udgt 5ud7 p0 ykb+type O.

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

3.Explain the role of inheritance in genetic diseases.