A man and a woman have a daughter and a son. Their daugh7 :d/fad9p;rrfqm3 thter has normal vision, but their son is colourblind. Which one of these genotypes fdh9 mq:3dr ;p/7aftrcould be correct for the biological mother?

  Which diagram shows the sev8wz(4tq 1.ji:2ejbg o d7obwx chromosomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdrag86kygvas,b18b q .qsfons. However, the result of a cross between two heterozygous plants yielded offspring with three 8qs8fs1bybg,q kva .6different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matchegof/j5 or4,lh9zcbm. 2b b6ctd to the correct definition?

  Which of these statements is a correct definition for * c.ecqgoiq/,2t ; vvza gene?

  The diagram shows a pair of homolw;x2er-oh ev//i6m+ y;y0oq lw d+yy eogous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific3 x wn2e.q h,glf/n0bm trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the w,/b0xf ne q. lnm23ghoffspring resulting from this cross?

  In some animals, the agout)jprc rb: 7p,oi allele causes individual hairs to have a banded pattern. The non-agouti allele causes hai7 p)r cop:r,jbrs 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 individualyv*rwa7k :sr4n18bf n pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled seeds. s1rb*fw8ynn7v:a4rk

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

  Neurons of the fruit fly (Drosophila melanogaster) have 8 chromo pv/n2wxz zw5*(l0veysomes. How many chromosomes are in a fertilised(z xwv5z0ew*v2yp ln/ oocyte of a fruit fly?

  When does the random orientcx0 ko. +/cvyms yf1;wation of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped,ro 2vt(yq6 x;ynh2er3 ;/nvpf meaning the exact locations of the genes on chromosomes are known. The diagram below shows one represen ytpv3qxn6;2r v2oye;f(n/h r tation 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 definitp1 efbh- y(*zfion of linked genes?

  The diagram shows a karyogram of a pq:df868xxa yk r9vhi.9g qr-n2a+tl brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosoixgtf+ -y.q k :6dapqr9xh v9n2a88lrmes?

  Mendel observed that there are two posy,a/o88h )nyvfs mi7gsible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white fho, sna7my8 gyif )8/vlowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of children born in London in 1wp87 js ve(v lr9yt ji::jwz(6991.8wir:j (vswz(vje7p t6: yjl9

  Which of these traits is an example of contincxqho thi(5 (s my k,v.4,oqn+uous variation?

  Which row correctly describes diploid and haploid cells inl5al7t f/ gjx s0)( suscz2wg+ humans?

  The following table shows the diploid chromosome number t wdomsn9his6+r h6*ozjjm/3. 7 8bk xof a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (H l v(*-qb3kjcgb$^S$). 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 type48na0k vpg8 mx O. What are the n840kpa mx8vg possible genotypes of the biological father?

  Which row shows the correcr f,ahayn33m6t annotation of the alleles for blood groups?

  Which of these statements are trmvpl,8g4)7a7t h ohkrue for 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 anaemia andgq k *a1ov:9r dcj;ne2i 2txr6y p)wv, the spread of malaria across* nyprvgx o2i9tc)q :v2kr;6da1,j e w 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 (Eq ysjpu-qnu536g 39avwuus przewalskii), 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) is du jw53 s69uq3yp-g navominant 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 genyxkg3 n8nig88 wr xyp(/a oy:9es.

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

Sickle cell anaemia is caused by /t-eswa:vg6shj5g c8ch+ 1x m the 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 homozygo c+-u;lhp .mjyijpw,,us for brown, long , jlcy piwju;+h,pm. -hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele foi mjgmc/c.m p7h::o6 xr diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant ov6 :7m/opc x: im.jcmhger 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 porsjb (bs n- n//iyx0( qr4q kez1/4zzyacellus), 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-hxq /0z niej r1sya(-zb sy44qn//zkb( aired 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 chamztx (pin0rx jbc0fth23 tx0 . ig(k01rt below? m . p xx1t0 xbgtk( jnif2c0r0(hi0z3t

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

  Which of these statements aboutamjtk3mg0eq33 o z2bhy *no-3 genetic 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 polygeni* r/chrh yb9j9c traits 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 th8o+ -8k 9wtg(y/fbpei1w puese inheritance of the disorder shown in the pedigree chart is X-linked recessive 81iwftew-bgk9( pseyopu/+ 8 and not autosomal recessive?

  Different species of living organisms have3 1orxon*(n w3qqph-i different numbers of genes characteristic to them. The table sho 3wioq -r1(*nhxq3opnws 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 charactuu1h2mneji6( pu3rv( 8tl qy-eristics of pea plants, including flower colour. If the pea plan meju2qr( 16th uyl3piu8n -(vts Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biolog,3jfoe2 afwg8b*8 jj uical female without hemophilia have a daughter without hemophilia. What are th3f j ga,2*ejb fwj88oue possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Heli4 .pe d(m9m. otswwnd9 bvk5.santhus 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 .e9 ot5(dnw d m9.kmpwsv4 b.svalue 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 chpkcc tm9;j e8lc5+d,gild with blood type Ogd 5c plm+t9c,8ej;ck.

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

3.Explain the role of inheritance in genetic diseases.