A man and a woman have a daughter and a son. Their daughter has normal v8, asf v+h/v lm,uc.+wsa:gvx ision, b8gvx+:vahwlsm +, , ua/fsc.vut their son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic +tjcm tc5y 2(ccell in a human male?

  There are two alleles for flower colour in snapdragon -iza0 cgsk+,ns. However, the result of a crosg+ik,z-ca 0ns s between two heterozygous 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 to the correct dej ;h :ntf 5dk;:x;jv7 dnnof;ds.uzo( finition?

  Which of these statements is a cora-1 : k-qhbeqarect definition for a gene?

  The diagram shows a pair of homologous u t-lrbooenfw 3gn215/ccf -5chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were c 15fgo3b9jjfbjg/4 bpzmmv0fl/t192jx ; enbrossed in an experiment. Which row shows tngbzf02 tfmj9j pv5 /e1bm3jb1gl9f4boj/;x he expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to ham3-p/ ,dgas fmu/ esag:)q5bx ve a banded pattern. The non-agouti allele causes hairs to be a sing 3/d/b-egpax) a5s, u:qms mfgle 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 idg 1d45yr;0-ekde t uoz 6mft8 g5fv0o+6lxslndividual pea plants was either round or wrinkled. The results of an experimental cross yielded 315d0466tk0e 8 oe gmzgx fod51;5fls- v lutdr+y 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 (Dth+ap5i +6t dbrosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of t6+a 5+ dtbhipa fruit fly?

  When does the random orientation of homoloqr. vu:y g2dsil*22emyn)h l -gous chromosome pairs occur?

The majority of the genes i)y*mb,/ xuzy.nq:fhin the human genome have already been mapped, meaning the exact locations of the genes on chro*q.f/ xh, :ybnuizm)ymosomes 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 dead uynn4 5:7ibfinition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Which ue6u1 q3hgi)))/;edtl gfhkm arrow is pointing to a pf ht i3el 6m;ggd)qu/k)h)1ueair of autosomes?

  Mendel observed that there are two possible sg fo3 syu)p:3:uj 3rwvariations 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. What were the genoty3uf3 g):yru:3s wsjpopes of the parents?

  The graph shows the frequency of birth weio)o2gbm:1c+ wixci ;f ght of children born in London in 1991. c;1i2 f wboo )igx:+cm

  Which of these traits is an exaokx.)y fp(-eioyc /j7 mple of continuous variation?

  Which row correctly des 01cxc5)aikz kcribes diploid and haploid cells in humans?

  The following table shows the disxsd3 j;7ja6 pploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allet4 72:ayem lc6d7l luvle (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 t)uga4qm1t g m3ype A had a child with blood type O. What are the possible genotypes of)qm4 ut ag31mg the biological father?

  Which row shows the correct annotation of the alleles for blood grv2gyp;a g3h)ans6)u ooups?

  Which of these statements are true for alleles? vvfl ;o )t.bpmz:9wj2
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 anaemiky,j s ,u aakg4sp. i1a, ,-t.yen5qbua and the spread of malaria across the continent of A,aa4u t-j.a is5 .,qn,kpyk s,eg ybu1frica.


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 numb 95 bk6xhv.zhmer of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to 9k hm xv.zhb56one 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 betweenfx lzy m. 6j(+w p.p( hsi)6ysyr7nn+d linked and unlinked genes.

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

Sickle cell anaemia isdh.yjj5 -i.q e caused 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 case*du1*; 8qismw d;xht that is homozygous for brown, long hair and a female cat th ;d8sq1 hixd;ews* u*mat has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacumedyhta +,so// officinale), the allele for diamond-shaped seeds (D) is dominan ah//otes +y,dt over oval-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 porce k fr2icu3j,u0llus), 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-hac,f0uj k2ui3rired 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 t zgtochs-g5v q5*ivcsj1g+,)he inheritance of the condition shown in the pedigree chart belowg) -vs5 itz5 csc1jg+hgoqv ,*?

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

  Which of these statements a//lx..,i cbrix3tv)l- wtjwg bout 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 traitsn7 g2au,g;7cs;aekh s can show 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 of the disorder shown in thav + ucqhu8-k:e pedigree chart is X-linked recessive and not autosomal reh cav:8q+ku u-cessive?

  Different species of livin-kdx)qz nx2wc;jj,mk6 7 zd q5g organisms have different numbers of genes characteristic to them. The table shows the esq2 mn;jdwj xqc7k) dzk5zx ,6-timated 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 characteristic 0(v5gbfuzw7znajj )4s of pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow vw4jz5f bja(uzg)n70 the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophilia het8n ,03tz+gk gjhjexk8/r57smix 6aave a daughter without hemophilia. What are the possible get er,a n gixk0/m 8kh+8gj56ts 7exzj3notypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthusjd* am0f (un0j annuus) to see if the genes for seed number and se a0*jm fn0u(jded 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 A1xh tzp 3 tx60ib:o2)ttmxva:nl kq67 and blood type B can have a child with blood typlk)omqt0:3b t2 tp1a6v ht :xi6z 7xnxe O.

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

3.Explain the role of inheritance in genetic diseases.