A man and a woman have a daughter and a son. Their daughter has6r,owrtai 7sv34s yor(lj0 r o,m1yw : normal vision, but their son is colourblio1riol7y rwvsa(,m3s :6 r4ty,0w jo rnd. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a ewg 0bw a/,m5xcf*mck :lbl;:somatic cell in a human male?

  There are two alleles for flower colour in snapdr 74,gebnvep ,qs lj6w:adc6,/i0xvdbagons. However, the result of a cross between two heterozygous plants yielded offspring with three different ,de 6w ,xv/ipdl j476c:bvqge 0 snb,aobserved phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct defg;v (ojn hc0o96 c1sodr +r-lhinition?

  Which of these statements is a correct definition forslvcyrtc80aha t6 2zn( ,o 6p* a gene?

  The diagram shows a pair of homolscd0x, jz kg0pc e, -poe,wb8:ogous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were cot+ ;a.gc1bp hmli7n5rossed in an experiment. Which row shows the expected phenotypic ratios of the offspring reo1+pn7c5h ;bl gi ta.msulting from this cross?

  In some animals, the agouti al z)f- xi:c9x xccdo5o7lele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colo)5x zoxfi 9oc-d :cxc7ur. 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 pea plants was either round (9i*mgs(lc uq)t0y im or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring witg(l )q9 ii*csym(0umth wrinkled seeds.

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

  Neurons of the fruit fly (Drosophila melanoct id +kl zb.5f3z15 p-lollxcy6k,4bgaster) have 8 chromosomes. How many chromosome 5t,l-.kz 4klop5lxyb1cfid3 clz +b6s are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome g) ) 7hvfs0h9thuvcb -pairs occur?

The majority of the genes in the humfc e:)ixf+* ehan genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous paic:efxe )if +*hr 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 definition of linked 5i9/ 8xuxwr8azde z 2rqor7w0 genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Whicx* x00fk pey+ tu;x r.yh17heeh arrow is pointing to *exx.7hr+ e1uykth0p e0f;xya pair of autosomes?

  Mendel observed that the;-a 9ihgc2*aelm7fepre are two possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flow2 c pemh9gaa fi*-7e;lers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of children born zc03x rxst4x; in London in 1991s;z4 txx03xcr .

  Which of these traits is an example of contizgkr.kj9 4amr/g01 avhe19 6naftdj0 nuous variation?

  Which row correctly describes diploid anzf+2na0*7hvjjgj i* v d haploid cells in humans?

  The following table shows the diploid chromosome number m*,dexn pd)w 6of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is causn/ba o cuol,oxwvm,* /brz +gdoa995 3ed 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 t)c5k rexq7jac 1a e f *ps3z7p+w)tz5bype A had a child with blood type O. What are the possi5je)5 p7*sxbfa+7apkcqr 1tzecz)3 wble genotypes of the biological father?

  Which row shows the correzy7+o *jzi1,iottf z3 ct annotation of the alleles for blood groups?

  Which of these statements are true for alleles? t46 nrq6lrew.c+3p zv
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 spread of malaria acti15hj:mjpc+k.qm43zz y :jg ross the continent oq1.jiyj5zcpmmz: t g+4 j:3h kf 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), fu 76zasiit v5*p.dz u0br colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant z50b aiiu7tz.pdv6*sto 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 and unlin(f9y:,.dtj* t txlmxeked genes.

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

Sickle cell anaemia is caused by the ai74shv3 wn l:xk0bbr1 qhwj45llele 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 hom)8s sgn5csr2c ozygous for brown, long hair s) sc25s rngc8and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacukz 9i:cl6zj,w s z,9yhm officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L)h:y,z6i,z 9lj s9kw zc 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) is dominant to sh(q ,wxsrbh/s6qc gze 1 5kcn* fxa)89sort hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male hf( bheq8s)zc g ws*q9nx x/r615s,kaceterozygous 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 inherita9ervq) -xw r*0 xk-ftcnce of the condition shown in the pedigree chart below? wr-xk)- e 9cfrvxt q*0

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

  Which of these statements about genetic disyhq l6pdeb: 98orders 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 normal8c -ox,zmt 5zg6v nw:b 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 pedina1nhpi j2u28a e93f1vyfjz /gree chart is X-linked recessive and not autosomal recessif j y2uie3p h nn12aj8af1z9/vve?

  Different species of living organisms have different nuxhm+czm*pkmf+)iy:bh5*-t cmbers of genes characteristic to them. The table shows the estimated number ob-t f:m5mh*++ hymc)xpi *kczf 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 floa)xxzj:be3wtq :1bt1 .t6q l fem+ob,wer colour. If the pea plants Mendel was studying can only be white or purple and fo:jb6 bxzmxqq)t 1 bw 1eat+ l.o,et3f:llow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophiliajls0el*b ;6+7 hilxq6n qni 2iun/a u; and a biological female without hemophilia have a daughter without hemophilia. What are the possible 2n us i luq+6j0nex7na q/ l;i6l;hi*bgenotypes of the daughter?

  A dihybrid cross was carried out between t:e2t,, jfbbgol6ke s) wo 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 0.05obs, ) ,g6kle2fbt:je 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 a-z0qa 6 (yqnil3eo a1a a .j7pyimtwok656zc2nd blood type B can have a child with blood ty5 w6m iiaceoz n z.o673 t(aalq6qaypj2 0-1ykpe O.

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

3.Explain the role of inheritance in genetic diseases.