A man and a woman have a:v77hrkyxi 7h daughter and a son. Their daughter has normal vision, but their son is colourblik7 7 hxr:yh7ivnd. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromos8s9k tpr5ima y*:y (mwomes of a somatic cell in a human male?

  There are two alleles for flower colour in 5u.8 p/sbranvnv/bd3 snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. bsv8ur 5/v3dn n.apb/ Which is the most likely explanation for this observation?

  Which keyword is matched to the correct defini 9x8wwmr e;yg-c1v2aution?

  Which of these statements is a correct x1cpu7p;79 za/ls uj8n l,s qd:x ;zgidefinition for a gene?

  The diagram shows a pair of homologous chromoso o;sfi dmgcbni+-58: hmes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an expe4(giyrj0bter hpdb .nn1;q4 8riment.rnj0 epqyb(;rhdt 1.b8i4 4ng Which row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a bi57gne c1wx jz:, zcxym1 g64uanded pattern. The non-agouti allele causes hairs to be a single cm zgx,:cj6 x7e4u1i zcw gyn15olour. 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 individual pea plants was either rou ; had 077mytjooo.gh)nd or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offsprin;jh0 7g) ydhm.to7oaog with wrinkled seeds.

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

  Neurons of the fruit fly (Drosophd 6 o/v7beuw9pila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a6eob p7 duvw/9 fruit fly?

  When does the random c2x 4cvng2vufr;q+7*ftz :j iorientation of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapawf m9j/n0crb cdh-u//m68 yrped, meaning the exact locations of the genes on chromosomes are ydbhc w n60r mj/a-rfucm/98/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 defini ,h:zg (vu5/tf7t plddtion of linked genes?

  The diagram shows a karyogram of a brown male rat (Ratt)h7 bhdt*q0j feu:nn 5us norvegicus). Which arrow i hb:5q tn7eu* hdn)0jfs pointing to a pair of autosomes?

  Mendel observed that there are two possible variations of flower colour in rtxq9*q6o x- d7unw g1pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flq*6 no gw- dqx7ur1tx9owers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of childro * 1odl hvmgikqa-947en born in London in 1991.i4 qkh 7 ao1*v9l-mdgo

  Which of these traits is an example of continuous va2a/f7lja u2 c3wve11n;fm qb-xar.v qriation?

  Which row correctly describes diploid and haploid ce/, h gduj3j 7ylg9v 7krxwkg4 5db10 1kf*hfhzlls in humans?

  The following table shqulmis3m(s4q9w + kc; ows the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele+d j-q6p 4vg fi3xc1ly (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 t0/1dtxona,i s e,pb c7ype O. What are the possible genotypes of the s,axtc e7id p1b0o ,/nbiological father?

  Which row shows the correfpz/vt -rvo p(z6zt-0 ct annotation of the alleles for blood groups?

  Which of these states0 8a+lgzpog 6ments are true 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 and themnx(59 bms5oq spread of malaria across the con5(5n mxb9 somqtinent 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 przew:sgx: a+on*u /pb* kuwalskii), fur colour is determined by a number of genes. Brown colour (B) is dg /:* uapnwk:x+ubso* ominant to 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 link9lac)jo38olb ky, ,zz2 6 g3mhb6yaq ved and unlinked genes.

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

Sickle cell anaemia is caused by the alleledp 178i2 pk6iemp2p mj 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 sho mr, l+8+hnwjqws a cross between a male cat that is homozygous for brown, long hair andwl+mh ,jqr8 n+ a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum -papj6/l9*ok ymu j/c officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) a9k j-py6* mca//ol ujpnd 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 to short hair (lakng ppzfn3w0;5, djz2 )s 2pl), 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) 2aw s z0 ppkpnz2;,n5)j gd3lfwas 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 pedis;7 j mr yt.cr h:uedi+mep432gree chart ;cpd ur72ym+emse.3:ij4rh tbelow?

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

  Which of these statemente )*-hyq4wzq+tom 31o tao-m ls about 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 polygenic traits can show a normal di h xecf9ebkjwjn/:48 j.qd 22fstribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  What suggests that the inheritance ofx kyj-cu)+s-2ldo,lq the disorder shown in the pedigree chart is X-linked recessive and not autosomal recey l,oq+l)sj--ku cd 2xssive?

  Different species of living organisms have different numf6b gr79 xq w2mw)yq-);ehes xbers of genes characteristic to them. The table shows the estimated number of genb x w2 yf-)q)x6g9s;eer7mqh wes 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. If 0m9 f )wq ,wopka+nzy,the pea plants Mendel was studying can only be white or purple and follow the rules of oz)ym,qnpk+ w,fa0w 9 Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a bdg.x uzor m8u/-ih7 y)iological female without hemophilia have a daughter without hemophilia. What are7 h-.d8gom/)u ux izry the possible genotypes of the daughter?

  A dihybrid cross was carried out bea,1o -du -it e) ua4(6nwc )l;tklwwfetween two sunflower plants (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 calculated value for the chi-squared test was 10.05; what does this e);w d)ctoit flk 1(n,u6lwu4 e-aaw- indicate?

1.Explain how parents with blood type A and blood type B can have a chi;ysnqgdx v9(+ ld with blood type Ody ;n+s(9xgvq .

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

3.Explain the role of inheritance in genetic diseases.