A man and a woman have a daughter and a son. Their daughtec-psd )w*q)u zr has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biological mq p))u dz*-swcother?

  Which diagram shows the sex chrom4raw r:jbw*. 2uh(rt) u(adrcosomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the result ly4xitx3h f1vny5x7 -1kmk: j of a cross between two 1 3hm: nkx xi4tv1fxkyy5l- j7heterozygous 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 correct definitim 8( d)d;vtkdoon?

  Which of these statements 40gydud;fylbthzt;v l;l2x p; 6um 36 is a correct definition for a gene?

  The diagram shows a pair of homologous chro p8, pxef-lwf;mosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed inep.1g lsnr)6t an experiment. Which row shows the expected phenotypic ratios of the offspring resultin.nr est)1l g6pg from this cross?

  In some animals, the agouti allele ch 083srpke,m6bl e);ur/yyq+e tms ;oauses individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous hasmy;8eq e0, bs6;/or ) ylek3+ptmur hve 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 od:/ w,culh*h er wrinkled. Tw:d uhec*,/l hhe results 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 (Drosophila melano./m3d7m upy s vde(bi4gaster) have 8 chromosomes. How many chromos ydu(/dbpme7ism3 .4vomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of3uxa i e7udq3o 43, ld ro/saztk-u6c5 homologous chromosome pairs occur?

The majority of the genes in the human ge5ntqir731 d zunome have already been mapped, meaning the exact locations 751nrt3 dizuq 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 definitm.23ls ;0anrizfleod czz0 sgs,(s 7+ion of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicusk+tps-c.xm2 cm64mdf1nngy /). Which arrow is pointing to a mf.tcg6ydcs/ mnm-2pk+n14xpair of autosomes?

  Mendel observed that there are two possible variations of flower coloufbh (oorfs .3+4foj+pxxuu/ ,r in pea plants, purple and white. After a genetic cross, the ratio of plants4fhj++ ou. s, ofu r3/fpo(xbx with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weiy 76ewzbgw pak 7/jqym3-lez**o:g 7zght of children born in London in 1991.-7agwqbeg zy m /z3 p67ej *o*klywz7:

  Which of these traits is an example o:ocgd0 saz7q( 8tw ,ukf continuous variation?

  Which row correctly describes diploid -o6 z8ni*, sy.ap8ubxv7afmo and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of specpdxlf4/rb39-d68pd x ,e s sxiies.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recesscf*kv 3:b)jrr r-1g gcive 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 A1 za5b38kdij1 vmp ym xtz.70r had a child with blood type O. What are the possib3dxa1m8 bivr7 k.zp mz jy0t51le genotypes of the biological father?

  Which row shows the correct annotation of the alleles for blood groups?6 *(hwlng* fer

  Which of these statements are true for alleles? 3b5b/ a7r* se t1ual rybg60kr
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 nn uq76xy z0pdenm24 7acr7eqn dnx 7042uyzmn p6oss 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), yk+6 wax/1o/h c.n/b8 wrku*yx-hx:or ej7hl fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P):r-xcrx//nk /yhox h 1l* ew8uh6 yakwb7j o.+ 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 d(t.vmj 9xf 7olinked and unlinked genes.

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

Sickle cell anaemia is caused by thejac6*8cdg;k v7x +1m p .ysrfz 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 cod5 -q:otw h;vzqyk oeo(/g7 kuau9a c8/7vt .ross between a male cat that is homozygous for brown, long hair and a female cat that77 9o tv q-w/kz5.tqo v(/ ugaa8e oh:o;cuykd has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamo+dde,g2gm ;+gu6u b rknd-shaped seeds (D) is dominant over oval-shaped eud;k, gr6+ug2g b d+mseeds (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), long hair (L) 3n bxk i 01 ,6n7)ats ypdbup+/pu0ugtis 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 and female short, straight-haired guinea pigs and a chi-squared test (χ2) was carried out on the s 1)u0u,0 pi+/ kpnb ytg3aptb unx6d7offspring.



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 inherita0i lnl0z+3 yyxmy o,t-nce of the condition shown in the pedigree chart belo+yxlzo,i-y t0n0y3l m w?

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

  Which of these statements about ge lgu:*f zt7ga 2*pwb9xnetic 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 trug:eyw.cb:qsw zc92qlp/m-/ co 0n.m mhk 1v.aits can show a normal 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 div (t*i r zcij( q51.qjw7*y8svp f7cqosorder shown in the pedigree chart is X-linked recessive and not autosomaqpvyt . orvq71i z(5(c 8ifq7*s*wjc jl recessive?

  Different species of living organisms have differeeah 705qkp) ownt numbers of genes characteristic to them. The t5) ekph0aow 7qable 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 flower colour. Ie31u;sp )*7hqdznamn nc )-of f the pea plants Mendel was studying can only be white orhno an)spn-m 3zu*7dcf;q 1e ) purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biology1s hgv2 ic1 bp7(izf0ical female without hemophilia have a daughtepzc01h 12ysi vfg(bi7 r without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plan m7c6,pczxtxbkp.x(8p, -/qp nkne s5ts (Helianthus annuus) to see if the x- ,68e q.c/bpsc p75,tp(nkmxpnzxkgenes 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 have a s t lu m//j-dh7k1(5oaujmw0uchild with blood typesaowm-l u0tuuj(5mj h1 // 7kd O.

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

3.Explain the role of inheritance in genetic diseases.