A man and a woman have a daughtc:yi9:wtr59jct0z 65hk aly qer and a son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biological mor :y:i6y9aj 0 9tqtkc5 zhwc5lther?

  Which diagram shows the sex chromosomes of a somatic cell in dvd m(pvh0*de*5 iu8ea human male?

  There are two alleles for flower colour in snapdragons. However, r 82h5pn6;bamk1xbrgw* x,pithe result of a cross between two heterozp p;x hi2axbkgr,56w rbm*n1 8ygous 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 tot f8jt6u4 1 qxjt9sl-eq v01pg the correct definition?

  Which of these statements is a correct definition for a74p nqayf( p;;yrmj -l gene?

  The diagram shows a pair of homologous chrod te;i9.lwis) yh+ ( 3wzsxr,emosomes.

How many loci are shown?

  Two individuals, heterozy;farqa 2v-tu6g1uoi ) gous for a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of thqaati-f1 u)o; 2uvgr6e offspring resulting from this cross?

  In some animals, the agouti allele causes ind7pw2x dy -ks iu0(( rnyp4z.jiividual hairs to have a banded pattern. The non-agou(niz pu0k2xdi4ypsy. jw (r7- ti 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 3olc*jcu 6hts 83f-gd eh:f c*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 wit f3 cc*judelgc 6thsh:-38o* fh wrinkled seeds.

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

  Neurons of the fruit fl8u u3p gx1yll2y (Drosophila melanogaster) have 8 chromosomes. How many chromosomes a y3u lp2x8lg1ure in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome pairs occg/oez +/r px7eur?

The majority of the genes in the human genome have alread4j: n qhsqh-n-ibp+, by been mapped, meaning thhn-sjn b+i ,:4q-qhpb e exact locations of the genes on chromosomes 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 definition of linked+d)k 8kw8o mzluw7*csl2l +jf genes?

  The diagram shows a karyogram of a brown malbnb0 ub+ :e wjfi qlb,t14h1w6e rat (Rattus norvegicus). Which arrow is pointing to a pair of aut, b1 fwj:bbi6hq we lnu10+b4tosomes?

  Mendel observed that there are t(pc5 s.s :yyecwo possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple c(y.yse 5cp:s flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weig emkg;,2 dbbz7j;1p tdht of children born in London in 1991t1bd;, zjp 7gk;mdb 2e.

  Which of these traits is an example of continuoucxnpt(h .c qpw1,v/x8s variation?

  Which row correctly describes diploid and haploid cells in hx clnkmqdtfc2,7w7:p; ;x- .q3hbhwrumans?

  The following table shows the diploid chromosoffb :jk 0pi orcya-;(2v0mk9v/(p b nqme number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (Hbbf:g i3r)3ypx $^S$). 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 1h6n 3x; wwnnsk8b9hmblood type O. What are the possible nm n6h9w3b1s; 8nhwkxgenotypes of the biological father?

  Which row shows the xvci f./-kp2 h+mo* ,z7eipkr(ck5 l1ysb w*wcorrect annotation of the alleles for blood groups?

  Which of these statements are true for alle,tu9oht 0gol1 kug(o5les?
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 cellyrw7emo2ws c q,+8m)e anaemia and the spread of malaria across the continent of Africa.+oes,c) rymqe 8 mww27


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), fupb29yaw9ymk9/zia,p q/4p dcz3 p*l yr colour is determined by a number of genes. Brown colour (B) is dominant tomd9c*k99z yiw/z/qpa,42 y3ayb pplp 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 and un)+ by2)mrbshg linked genes.

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

Sickle cell anaemia is caused by the allele H*-y+lat 2a nlx49.suepvswv ( b$^S$ . 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 aq5h i24tnjar /3wavgq90 l;ch cross between a male cat that is homozygous for brown, long hair and a female cat 45h9hi 0;qglaajq c v/w2rn3 tthat has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shapsn7 h-p05:e qni hrw ),y4ebjied seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short sr)jen w0qiy5nhh7 4- b,ise:peeds (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 hr1tbsdsbth j-(x,70 p zy*z9s n l0x3vair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was0vb91djx3(zltps ,0z*nb xyhs-7 rst 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 condition shown in the pedigree chartiz9tn o.:oh lx/wgc 3 7oou*3e 3l.gohz* /ew9oct7 nuoo i: 3xbelow?

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

  Which of these statements about genetic disorders u z28lohc; c 396dxyfy,dhc1tis/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(o6px3 0a3chowq+c-o 1sn7t1 itar ewion.

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 , nyb5y znkgj0:dduse w).*2mthe pedigree chart is X-linked recessive and*jnn2,e0dygu y)dsw5m:k. bz not autosomal recessive?

  Different species of living organisms have dkldlk.i1kd jw z0t o- +t5p3l)ifferent numbers of genes characteristic to them. The tabpwdl1l k3kz-t0do +kj5.t) lile 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, includi0bsll( /t 8zlsng flower colour. If the pea plants Mendel was studying 8b/tzls (l0s lcan only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophils,a fz5 pc(1ybia and a biological female without hemophilia have a daughter without hemophilia. What are the possible genotypes of the daugha ybc zspf5,(1ter?

  A dihybrid cross was carried out between two sunflower plants (Helianthuss+bpycv. k2r . annuus) to see if the genes fok+csbyv r. .p2r 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 t h/s4pljt.;ctype B can have a child with blo pct./js4h; tlod type O.

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

3.Explain the role of inheritance in genetic diseases.