A man and a woman have a daughter and a son. Their daughter has1q5lw if/ iux: normal vision, but their son is colourblind. Which one of these genotypes could be correwi lxi:/fuq51ct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a c; d,(bq*gdulpjw4 o.u) ha4bhuman male?

  There are two alleles for flower coq;mi gjo- )qgz5 w 1h9jwnhr)lr +29uzlour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observ;jn qi h5uw 1jz gzmol)9)9+r qhg-wr2ation?

  Which keyword is matched to the correct definiykhpoy+ai( oc-l 67v *tion?

  Which of these statements 2c c3)1tiocuup z:d6+ah2 yszis a correct definition for a gene?

  The diagram shows a pair of homologo 7 j wupbxde:/cyj9nv g:91nlaf8b9-mus chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific traitv7s /9zjzw4brna:q5ucw )bg ), were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting /wnc b )j:r4wg zv5u97sab)qz from this cross?

  In some animals, the agouti allele causes individual hairs to have a banded patwfg s8(:m y2bitern. The non-agouti allele causes hairs to be8f b sg:y2w(im 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 sed(*vlr :x.jnnvsvx3;)/e whled 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 l:*. jv;vhls)n(rxd/nx w 3evh 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 chromhgay5sq;l1 5 josomes. How many chromosomes are in ; 1 slgh5jqa5ya fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome pairs occ f9 e-cpqgs cmm178el.ur?

The majority of the genes in the human (h-y-,vqj/ltss8dxyn od vz:u 4x 0q7 genome have already been mapped, meaning the exact locatis0:4-,( 8vzynqu7x jq s xh-ytd v/ldoons 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 47ae cas.hmr*of linked genes?

  The diagram shows a karyogwkmg h 11o :r0yukz9f6yc,;rwiw d 0rl:nv 95vram of a brown male rat (Rattus norvegicus). Which arrow is poin5cw09nl:ir16hk rw wvgf;z y v:,r0 y9m ukod1ting to a pair of autosomes?

  Mendel observed that there are two possible variations of flower col6bc7 cic elm:+our in pea plants, purple and white. After a genetic cross, the ratio of plan6 c+ ccel:ib7mts with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of p1l k9fuo33xlchildren born in London in 1991.3luxflo p 91k3

  Which of these traits is an exsun3m2hv -v1 aample of continuous variation?

  Which row correctly describes diploid and haploid cells in ckp v jk(,ltf9y)89 fwhumans?

  The following table shows the diploi7s7ye2sxj a 5wd chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is; )6ug w c397upecqi2/h;piy yv).pldgm7o dr caused 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 wpmwsi+pd9b-nz+wru7l7 *, pd 2r3n zoith blood type O. What are the pod93rzrp ppw*7 +-+n,ilnuz o wm72sdb ssible genotypes of the biological father?

  Which row shows the correct annotatiq-f o o ybbk by-qsn2hzh0+fg 16b7/3xon of the alleles for blood groups?

  Which of these statements are true fon)9(((ssmwm4jxv,sv 9 i uzzy un1oh*r alleles?
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 anae hz569 r)ff(i9xbnn nn ax3za,mia and the spread of malaria across the continent of Afric na3b6 ir9(9)5anhz, fxxnnfz a.


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 determ 2xr5tec3* d ./h(qxu7ty1b he h6kfzcined by a number of genes. Brown colour (B) is dominant to sandy colour (b) antc k2u/bh1hc5ee t 6qf.*h3(x7 rydz xd 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 unlinkjen/e 4 u0d8ko6zs8tboz:3q;m1x n m ked genes.

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

Sickle cell anaemia is caused by the allele Hubef7lki-tl+pzu.4qc nv17 p/*e iu2 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 a cross between a male cat that is homozygous for brown,h ,8 2:du8tjh)u g;gyyciox-q;kbsl . long hair and a femalej d khgx ,ygc-:2y)sul.8hb u itq8;o; cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officizv :6ivifb3x:+0egb pnale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominanezi+b:f3xp v: 6big0vt 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 (Cavialvp+b h7m(x:pl ,(pp /lis*xg porcellus), long hair (L) is 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) g7llxs pm/b h: il,pv*( (+pxpwas 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 ehmqw +8s15jqmmc7z 1bp7 d2 vthe inheritance of the condition shown in the pedigree chartbq+ zpeh1q12jwm m5d7 cmv8s7 below?

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

  Which of these statements about geneti)8f,(9unkcv h nkwex 8c y18ux m62*nozzhrg2c 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 trait73 8)r7 g(erhdq2-jl9w4 r( set u n3gvklnkvis 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 inherir+n,(n6l .ja +)7 c2ulnl s ujcbgeix0tance of the disorder shown in the pedigree chart is X-l (0rs i2)u6lc7l bcx+nen.+ jan u,jglinked recessive and not autosomal recessive?

  Different species of living organisms have different numbers of genes chx 66wlm )1bqdy ))zyanaracteristic to them. The tablexwnmy6z))la1 b qdy)6 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, is .qk8yt2 tk6yncluding flower colour. If the pea plants Mendel was studying can only be white or purple and 2s86qy t.ytkk follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a b x3t01ba hno(d*taz v2/nia7 viological female without hemophilia have a daughter without hemophilia. 7n1b txatha* nvdva(z/32o0 iWhat are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helwlo q48+dehd)f0 +* p uuxhgd-ianthus 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 calculated value for the chi-squared test wdlu *qf 4h8xg-)+p +ud0ed wohas 10.05; what does this indicate?

1.Explain how parents with blood+zd:sf bkyftw z m/z.z-.(m)d type A and blood type B can have a child with blood typekmzz)zt d( mzwffd+s.-y: b /. O.

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

3.Explain the role of inheritance in genetic diseases.