A man and a woman have a daughter and a son. The9:l -*onj iaeu3f.*xjevxax..y 9dv x ir daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biological mo9-xa.n .:jx 9e*xfli.x udoye*3vajvther?

  Which diagram shows the sex chromosomes of a somatic cell in a human male? k0 ht6vvekj50

  There are two alleles for flower colour in snapdragonsib+y ; -/v vs8gve 9mu6exlp0y. However, the result of a cross between two heterozygous plants yielded offxuiv;0bvm+e/es68g v p-y9y lspring 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 dc ok: ohymo3y3yc p:w6 g*0fv)efinition?

  Which of these statements is+azfk(6r(w0b 9 rlznce pjb-( a correct definition for a gene?

  The diagram shows a pair of homolo.xk rm.t(j 1puob ,:wygous chromosomes.

How many loci are shown?

  Two individuals, hetero)p4b33cm z/.ixhkod ; ckrw-dzygous for a specific trait, were crossed in an experimen.h dokw-dk r/);3m4cz p cxb3it. Which row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele cause luh,l15ymve-bk b)cz 2+,hk ss individual hairs to have a banded pattern. The non-ak-cvb+s2y b hehm),1ulk l5z, gouti 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 pea plants was el2jc)v-vpk( g0n i: rxither round or wrinkled. The r(g2cpi) kj-xn l:v 0vresults of an experimental cross yielded 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 (Drosophilarw0(*3a;x zxe:soss j +9j hif melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocytjw+;(:xijss o x er0a9 3szhf*e of a fruit fly?

  When does the random orientation of homo q;xg hmkn-11zaihbb px--x. *logous chromosome pairs occur?

The majority of the genes in the human genome have already been mappe(b;5ryunxlu e+ ,t9kaqf8 z*yd, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of c; yk9r+eu,za8f 5l*(yqn xtbuhromosomes.

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 oyg:c 08nayrwk*4p qan.9iy1 cf linked genes?

  The diagram shows a kasx3kv o(fuq9/ ryogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a 9vu qo(/xk3f spair of autosomes?

  Mendel observed that the nae*zw7()vu rre are two possible variations 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 geno u*7(ewa)nvzr types of the parents?

  The graph shows the frequency of birt u .ndnt m6z05rt;eac3.; ordwh weight of children born in London in 1991..t6.mt;e5 nz do3r0; ncarw du

  Which of these traits is an example of continuous variat+sib9; nvb(6r*ixon kion?

  Which row correctly describ;(g 0p z.a3gt1. +aoxlqvyirnes diploid and haploid cells in humans?

  The following table shows the diploid mb h;c34 mx k; 310/cmbivqxccchromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a a 1,m cw:,3b yujqqv*ub)sdj: rp fqy,.+od,g 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 h:q g:4kbl5:z w1cxxqj ir5j/cc:x9 load a child with blood type O. What are the possible genlr qx5 :j /xl cx q:gicz9w:ck:1o4jb5otypes of the biological father?

  Which row shows the correct annotation of the alleles for blood grourscz q 7t.8 yt-5a-mawps?

  Which of these statements are true for algp:ng1m1iu 8 qf4us-hleles?
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 vqik8h) p*wg 1anaemia and the spread of malaria acros ig)*w8qp k1vhs the continent 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 is determined by a number u zv2ss3: guz-i;y7wvof genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is domy gi u 7v;32zvswu-:szinant 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 and unlinked9f k4a xsji+w b/f4;lq genes.

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

Sickle cell anaemia is caused by theee12zy pu+dk2xia,. qd:oaoruw:-a 6 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 9f(5jlujlo ee c.. ,iefor brown, long hair and a female ca.c,9e.u5 e jlolfj(eit that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamow5b4l z1by3pz j) r4kn3yec;xnd-shaped seeds (D) is dominant over oval-shaped seeds (d)zc nw; 1l4 4jz5b3)y3kye bprx 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) is(2dx(3vb8yh 9vzshw w dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out betwb8w( zdh(3v2ywx svh9een 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 conditiou1 5 e4rtujd*rn shown in the pedigree charte*rr1d45uj u t below?

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

  Which of these statements about genetic disorders is/avb j 9r/7j:ugzz2k uap61e wy(re 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 distribution t*.g 6 uw4oqup,ltv2r.

2.Outline the differences and similarities between homologous chromosomes.

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

  What suggests that the nat7 5 :w8ce *tc27aght0ueqzinheritance of the disorder shown in the pedigree chart is X-linked recessivee*wet5 th7c07: zug aca2 nt8q and not autosomal recessive?

  Different species of livingrs j5;jsld 5h1 organisms have different numbers of genes characteristic to them. The table shows js;5j5h1dls rthe 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 zmdw ,hq8c3d:an 7wfh u6 1q0kcolour. If the pea plants Mendel was studying can only be white or purple and follow the rules hwzq7dfm dn1 q:k036 u, hcw8aof Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophi/w- ,mdacmr -5kna -kclia have a daughter without hemophilia. What are the possimkn-m-d -ar ,kw c/5acble genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helian0 hts8 k v+jf6np edodrr:284pthus annuus) to see ifp8 rjkfdt 4s:v 2oe0nrpd8h+6 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 bljla.gk k j44xy4 ldgk2)ve0 we:.7kssood type B can have a child with blx2 l.ke47l d4)gkj4gevwssy: a kjk .0ood type O.

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

3.Explain the role of inheritance in genetic diseases.