A man and a woman hav ldf6mf,;rnh9xv3t f)e a daughter and a son. Their daughter has normal vision, but their son is colourblind. nxh,)lrfdf;f6 v 93t mWhich one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic ce429m 1bznecpjll in a human male?

  There are two alleles for 5avja3 v--.qt a dz5lfs*ls /hflower colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three lvz/-a5-.vqsf3h5a l sd*tjadifferent observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correc+w19 i ve3rke/z:8 qzaf/t z7(. qou-pvvinne t definition?

  Which of these statements is a correcta tr).xo l(z+ej j7g)n definition for a gene?

  The diagram shows a pair of homologous chromosok5jp:lqf kro3rwb - eb;nc0/*n/g ,f rmes.

How many loci are shown?

  Two individuals, hetey2g(p ougz; i;rozygous for a specific trait, were crossed in an experiment. Which row shows the expected phenotypic rati zog;;2 iguyp(os of the offspring resulting from this cross?

  In some animals, the agouti allele causes indq o)dch8ch)5kzqw- /kividual hairs to have a banded pattern. The non-agouti allele causes hairswk)h qh5q/ z8 cd)ock- 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 pea 9)7 e8d 1hch7qrigf,dfpm 2wjplants was either round or wrinkled. The results of an experimental cross yieeipjgh fdf2 7h ,q19)md7cw r8lded 315 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 (Drosophila melanogaster) have 8 chromosomes. Ho,pbv(oc 2s;v dw many chromosom vsb,2pc od(;ves are in a fertilised oocyte of a fruit fly?

  When does the random orienfp3st/gd 7r( .gn;+3 appfigytation of homologous chromosome pairs occur?

The majority of the genes i py(-1nhkatf1m5 ao(wn the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a ho1 htm1(op-5f(wny akamologous 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 definition of li-vi+ sv )ft+n0.zuddanked genes?

  The diagram shows a karyogram of a brown h5v o tate+e54male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosomvotat 4 eh5+e5es?

  Mendel observed that there are two possible variations of flow4.iwhla6(d cher 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 d4wl ch. i(h6awere the genotypes of the parents?

  The graph shows the frequency of birth weight of childr :68h gsy ad:sa;bz2kt 4irl)yen born in London in 1991.2l:r8s zh;ytyg)sdaib 4 :k 6a

  Which of these traits is an example of continuous vas .)fhqeo -nwa,7x sy0e-v +znriation?

  Which row correctly desc hw69pzm8j8hmx9:l-lay 1c m pribes diploid and haploid cells in humans?

  The following table shows the diplykqp.0si p)muq q3:y t 31)fdcoid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (Hvx (me1;ofhw1b$^S$). 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. mj5djw2) 5wyvWhat are theww525)yvd m jj possible genotypes of the biological father?

  Which row shows the ck. xw ;xqg wfm/:it9c zvnm./:orrect annotation of the alleles for blood groups?

  Which of these statements are true for o5u284gmdyi jc.yp 6ualleles?
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 ny6;kzcaf vr8ptk0 v sc3nc57(i dt++the spread of malaria across the coskc 3vkd8i 5 +cpy+6;znr7( ncta0fvtntinent 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 isa.v ,zn;rg k7ne.c7 uo determined by a number of genes. Brown coan nz7ov,keg7u ..c r;lour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (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 linked and3iav6nk 4y 5nb unlinked genes.

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

Sickle cell anaemia is causj 5v8azhq4 4n ai3qre9ed 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 for brown,z8)vxu aejdn0-padl9 t 0glit/ 2 nix bu3o05- long hair and a female)30i0zg taad / t0nlx-8jv d u-2 xneoupil9b5 cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-ul+ cv.p n4:.f;lnojeshaped seeds (D) is dominant ove.on. v en;pljf4+lc:ur 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 porcellus)1ox2(7vfqxm ,:q r:vpl(u nvr , long hair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight h qrpxvn(7,u 2v (mvxq rf1:ol:air (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 condiqoxzsm/eq/m*r ye .p 7eon+eyp 8n*7,tion shown in the pedigree chart px /+y,y8z*7pe/nq.n qm eeers*7moobelow?

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

  Which of these statements about genetic disorders is/are corrdxa+9yp)w6duyn o6 h6 ect?

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 distrixa 7p q oc,r; i;6+s(fbujp3qtbution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  What suggests that the inheritance ofd*:;g vil ww9-vqk ma; the disorder shown in the pedigree chart is X-linked recessm lwg9-kqidv*:a;w v ;ive and not autosomal recessive?

  Different species of living organisms have different numbers of genes characterwgsb.5 ne: 1pgistic to them. The table shows the estimated numbe .pw1:bggs5 ner 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 colour.+ f of:a) q v98tza+ ;5fsoias1fuoh5o If the pea plants Mendel was studyinovft9qa+518+o) :ozhf ia5sf u oafs;g can only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female with:ebp+vue h1) kout hemophilia have a daughter without hemophilia. What are the possible genotypes of the ) v upe+bek:h1daughter?

  A dihybrid cross was carried out between osw2 (hq0 3l9zd hf5x5vwzi;otwo sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical val5zxw2z0 h vfdh5qi3(;w9s looue 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 bl:0z2lksfru(jf ;h j*mood type B can have a child with blood typ*rjmfs l: h ;juz(k20fe O.

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

3.Explain the role of inheritance in genetic diseases.