A man and a woman have a daughter and a son. Their daughter has normal vision,vj;x: zmpj*0n(sn 5 o.xedw: b but their son is colourblind. Which one of these genotypes could be correct *oz vbnjnjmp(x :d.ewx0s:; 5for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell ir 7psye-5 ighhp f4/z5n a human male?

  There are two alleles for flower colour in snapdragons,*5f 3w.x njob 4ynawjk ).tou. However, the result of a cross between two heterozygous plants yie 3yb5n .njo)aujw*wot k,f4x.lded 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 definitionru;ov 8lafm tl4ey(8,zk: z*n?

  Which of these statements is a correct definition for a ge6 ;g ak tj3(o;zdgzv 3.vkch41xt zo*sne?

  The diagram shows a pair of 9d q3zl1s tx6icc1zhlr*vrtx 5p1:g/homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific tr oda39xy9q k+gait, were crossed in an experiment. Whic+oq gx99 3dkayh row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele cagszpor s)c2(o . 0im6.welmx5 uses individual hairs to have a banded pattern. The non-agouti allele causes hairs to be ag s.5 2wlo ce6p0(mizmrx)so. 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 inub)b75yj3 cz8ee yy8ydividual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspeuyz 38b5b7j8 y )eycyring 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 (6tdf/lq09ta/(fo8xck x + bobDrosophila melanogaster) have 8 chromosomes. How many chromosomes(blf /kotc /x8x+06tdqoaf9 b are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homol aw;5r+ijbel3 ogous chromosome pairs occur?

The majority of the ge gfc 5 1nud85s-gqmxf2nes in the human genome have already been mapped, meaning the exact locatiofg25-8 mng q dc1u5sxfns 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 genwvxu(4js r.h: es?

  The diagram shows a karyogram of a brown male rat (Rao.; gpb/if iy8tc 4zns8 / xpp0+f4jxkttus norvegicus). Which arrow4/ pxj+byfoii g 8 k.8npcxs4fz0p;/t is pointing to a pair of autosomes?

  Mendel observed that there are two possibd u5hrs8dno4k4vr83u le variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flow4do4du 5nu38k8 hr rvsers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequeg(7 /z2n.b* ywkmtf*rn2 hzlyncy of birth weight of children born in London in 1991*wyzt k7/h22.*n yz fl mbr(gn.

  Which of these traits is an d;iw6ot1 ala 0example of continuous variation?

  Which row correctly describej72s1(* y8zeqr iptqe s diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of speci eqs(wq3ez)gozi(f8:es.

Which of these statements is correct?

  Sickle cell anaemia is causet7s zo6 rn41n tqj+nx,d 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 type A had a child with blood :t33/ shy,ecuy ld4xetype O. What are the possible genotypes of the biolsyxye 4du3 ec: ht,/3logical father?

  Which row shows the correct annotation nd2u akavg*(5 , nw)oaof the alleles for blood groups?

  Which of these statements are true for allefrd;cld+- u378 d pvfales?
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 o og;q(gt2mxt2 2gww1jf sickle cell anaemia and the spread of malaria across the cont g( jgw;go2 q2ttm21wxinent 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),w4bu r1 qr.ihv 23au15qjc gc2 fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colowac5 u 1u1j3 hbcr v2.qgi24rqur (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 unlinked genes. hpt)p9cz ;zw5

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

Sickle cell anaemia is caused by sm5 l c9;2z7 wf;sqiapthe 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 mal4g 6l6 gu5nabee cat that is homozygous for brown, long hairle6g6aub 4n5g and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped seeds (D*jrl u fj(f5aa/.rvf-) is dominl af/f5v. *u(afrj-j rant over 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), long hair (L) is dominant 4 y6-o56z 2imw(mgl 99gsebyan7oazs 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 guinem7 4aozya2lm (yeg6n99ibs 5w z6o -sga 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 xlvwrq(-;(v1 tg a ;qzof the condition shown in the pedigree chart b1r q xw l(qt(;vag-v;zelow?

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

  Which of these statements about genetic8kfzxx4gj. 3xwzawut ),b+y7 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 1o0*imv /oyd1h odgq l-)ry uv-6hf s8traits 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 disn 8k0zoog,xk3 ,exu:o order shown in the pedigree chart is X-linked recessive and not autosomal recessive z:neug3oxoo 0k8 x,,k?

  Different species of living organisms have differenng w4z1 mf3elb1ut *4ot numbers of genes characteristic to them. The table shows the estimated number of genes for five n4zu 4l mtf1bg *31eowspecies.
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 fym3afoeq( +wj jt57 2clower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statement (qam3t7cwf2jjy5 o e+s was correct?

  A biological male with hemophilia and a biological lr b.+zbjb-6,u i:(gl7gsewkfemale without hemophilia have a daughter without hemophilia. What are the possib (l:s7 .bz iu,eg kb+-lwjb6grle genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower planf4-jhy5zgyei1 *8l3 9dwxk i qs(xu4e ts (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 0.05 significance level was 7.82. The ci*f kgxyj95hlwzs e (1 q8y4-4exd3uialculated 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 ez e ;.6x;j nj33etbc ft9;fv+ckoce6have a child with blo;vexz.6+ktj 3oc e; 93jf e n6t;cbecfod type O.

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

3.Explain the role of inheritance in genetic diseases.