A man and a woman have a daughter and a son. Their daughtec9j x p1x5;xhqbwxc -wfk16 5dr has normal vision, but their sonxw9-j;dpk5x5c1 bqh x 16cwfx is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a cw+63(bgj*y dbem u;b human male?

  There are two alleles for flower colour in snapdragons. However, the result ofdwnc*r: e,.ofpn;3 s5 au -:kkt pwec0 a cross between te3wpfc,e-d0 k.un wc atp::o skn5*r;wo 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 corre0f fq5yc:jmucwf5/ )m ct definition?

  Which of these statements is a correct definition forqj+1s, u+qki n,j 9s;smc0jzgwza +7f a gene?

  The diagram shows a pair of homologouss5.xvs+g t+ zs chromosomes.

How many loci are shown?

  Two individuals, heterozygous forq y85cnvjggp r(q+h ); a specific trait, were crossed in an experiment. Which row shows the expected phen rj5gpq +8vny; hq)cg(otypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a bande4/ rug2r ryjj7k33h5 85wdgj7hhrpu yd pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs with adj72u gr8/ry4w u7y hp335 g rjjkrhh5 banded pattern.

Which combination of parent genotypes would allow for production of offspring that do not have the agouti characteristic?

  Mendel observed that the 8 qm97dt-ye)a dfmse:seed shape in individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkl7d -eq9:f stady) 8emmed seeds.

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

  Neurons of the fruit fly (Drosophii6 lz11t 4qsdn4wip3y e 5cfzn7p5na ,la melanogaster) have 8 chromosomes. How many chry5w,q5nie64 4 npl3dfpzznc1 sit1 a7omosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologoe 8ipmd1rtvpvi l)am: 8mo9. y*h,kn+us chromosome pairs occur?

The majority of the genes in the human genlrxn 6d1f1/ny f8j+ wdome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows od/8 xw+nnf fylr 16j1dne 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 15y 7s rfsys5ujg)7vmnition of linked genes?

  The diagram shows a kary7gcc,v1 2zl*utv o6medj 3/weogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pz723wo16 *jcctl,u/egm e v dvair of autosomes?

  Mendel observed that thipvsq6 mn q34*ere are two possible variations of flower colour in pea plants, purple and white.iqmpnq46 3vs * After a 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 frequency of birth weight of childrnd 9 87 nymrq6e6nvr1hen born in London in 1991. rr9v 8ey q6n1 m6nhdn7

  Which of these traits is an e3ste lvc1ns3q .,s ny,xample of continuous variation?

  Which row correctly desc6x.c/: oh u eh;xgh*cdtc16 jhribes diploid and haploid cells in humans?

  The following table shows thems1bkod ;.p p-j qt3j7 diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia i12wwlexggmq cbor* 8m11yl ;5s caused 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 bf8)o, pza 7 i 02xdshpska0pn(lood type O. What are the possible genotype02 sp,k)h anio70 fp8a xz(spds of the biological father?

  Which row shows the correct annotation of the allele-hvu5,9he zu vs for blood groups?

  Which of these statements are vjr*edquyz()i3gw1wsl4 /u* true for 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 sickle cell anaemia and the sm+*ki- g1j iay;+ocndpread of malaria across the continent ofj myn+g1+c;k -iid a*o 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 number op79rp ci( 6yt(p r8bapf genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) col(p9by 68 rp aiptr(7cpour (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 lin fghip3yio y89-t9p 5qked and unlinked genes.

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

Sickle cell anaemia is causqn 6b 0job7w2luz 8r8red 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 b37rrtn6cih ;g etween a male cat that is homozygous for brown, long hair and a female c37 cr;6nr hgtiat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shape dz rww4+ fg jlmp8as:iuz/;;3d seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (u+s3zww ;mf8j dlaizp4g:;r /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 porcguc2uf 28wj sebx2.;gk lj*s6 ellus), 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.6 kjc2jeubuf2xg2 wsl ;*8sg 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 inherimo j 1yj.sz1z+)g qd9vtance of the condition shown in the pedigree charto)1 + vzsd. jjymzqg19 below?

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

  Which of these statee c7mwv6)q)d uments about 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 distribut jwu 2vu/5/tstion.

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 t+ d,i zsxi-n:lhe disorder shown in the pedigree chart is X-linked recessive and not auto:s ,lxz+idn- isomal recessive?

  Different species of living organisms have different numbers of,z1r k-vr :sed genes characteristie-sk:v rr1, zdc to 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 characteristics of pea plants, including fyih s *ykj-7qnru /4h)lower colour. If the pea plants Mendel was studying can only be white or purple and4h)- r /uhs ykq7n*ijy follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemoph7zdx w,09ca gb e3v.adilia and a biological female without hemophilia have a daughter without hemophilia. What are the possiblx 073bv.eaa zcdd, g9we genotypes of the daughter?

  A dihybrid cross was c 1fkb+u7 g.p8za2.pke y /ukwuarried out between two sunflower plants (Helianthus annuus) to s+w1uu.aekpf8 2pzu 7bygk/.kee 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 indicate?

1.Explain how parents with blood type A and blood type B can havh )jb t mpi1 9e/fgkmyv)l65c,i6jea0e a child with blood type O. hjg09b6/e)m5ktl)a ,c1 p6miivjey f

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

3.Explain the role of inheritance in genetic diseases.