A man and a woman have a daughter and a son. Their daughter 4go.hvo7xt quhe,7z , uxi 8z:has normal vision, but their son is colourblind. Which one of the:q7 eutx,8,7ogh.u hzzx4ovi se genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cel.x3fj( ftf1g ne up*6xl in a human male?

  There are two alleles for flowbb-yr/*hr gay c153j3shgynw.v 8i5 xer colour 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 r g. ba31/bhjciy85hxys3vwr-g yn5*observation?

  Which keyword is matched to the correct definitiy ,0p dnzy0i b4i9wpw0on?

  Which of these statementsg gwq9z u9i7g fii31bbt3 ;rt. is a correct definition for a gene?

  The diagram shows a pair of homologous chromosomes. 98eb lbe7x4s+zmo *wl

How many loci are shown?

  Two individuals, heteroq6hq0 ,2 zrcrozygous for a specific trait, were crossed in an experiment. Which row shows the e2orq6,0qzr hcxpected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to h-/6tsna6lr8t bln.i a4 ( vtreave a banded pattern. The non-agouti allele causes hairs to be a 4b8r6sv .6 (tlai/lanttnr-e 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 sej98o ebts,u9 red shape in individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 of os9b,ejt8r 9ufspring 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 melanogaster) have 8 chrbajq 8 d*j-xy*l8vz6;fuff-g bj6-h f omosomes. How many chromosomes u 6 6q-8hj-fx*-8djfyfb zg ba*lj ;fvare in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosomer-o uwdl (8uv(;gal 1s pairs occur?

The majority of the genes in the em.ys *i2 sjd m h:mwi;7l;c.rhuman genome have already been mapped, meaning the exact locations of the genewshcejy;r immd im .l;27:s.*s 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 correctz(yk48d a frv1f8 .wfd definition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Which arr535i .2u rkrped-:mvwdw p)ev sj3mo/owm pewu)o2:d.pv3/ w- 5 mr5 rj3vsedik is pointing to a pair of autosomes?

  Mendel observed that there are two possible variatiol b /(h0sj:p:uvxqqg2 ns of flower colour in pea plants, purple and white. After 2q:x:/hpvq( s b0glju a genetic cross, the ratio of plants 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 children born in London in u710ezsm q q2(yg v;yf1991yqv;ef7qys uzgm( 102.

  Which of these traits is an example of contibby u0(4 6xfpmw3 afl/nuous variation?

  Which row correctly describes diploid and haploid cells.i0zv (d9 rq+dd;ni jx in humans?

  The following table shows the diploid chromosome number of a range otg)8 4txuekwn5gv4 6 dep g(z5f species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessivyld c:g,.8ryzp( opz twe7k27e 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 type O. What arvn4si.t w-hw *e the possib wn-.4ti*svwh le genotypes of the biological father?

  Which row shows the correct annotation of the alleles for blood 0u a0o13sas ick;ag;igroups?

  Which of these statements are true for5sg zbelih-2mvtn; qgq) q 7 yc223s/o 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 the spread of malaria ac4otvn44t5a0yrr uoy6+ums:tross t6soyrtr t0n:4+ 4am4uvy u5o 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), fur colour is de 8;6ev dthjh7jtermined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) coloje hjh8d7vt ;6ur (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 anw9hnyfz7 o;zkd 1tg68d unlinked genes.

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

Sickle cell anaemia is cayderki) f3*g*- 8uxcl used by 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 c:+th qbi.aa le7rtxcf.5.zc te4 ;/0 j9cudexat that is homozygous for brown, long hair and a female cat that atf.bl:t de4ju c;c0hqt5.ac+ .e 9zei/7xr xhas black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shap-.0rds-jcn+ qdai/y led seeds (D) is dominant over oval-shaped seeds (d) and the allele for long +iq n- cy/. -adldr0sjseeds (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 porcwo4szbl bufq /t7a+3 k.m1ab: ellus), 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-ha w+/b3aqtob. : bmk1s7fz4aluired 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 inm gs 4kyeb*9 qtbhj54zoac0 .5 the pedigree chart 5kec40hbzqm oay .j95 g*s4 btbelow?

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

  Which of these statements about geneticb 6ezie;xoeyw()oa,s)b h7 w+ 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 d ;ys8i7 kwaf /wy)2)til9 datoistribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  What suggests that the inheritqf):vg y 0zdfzm /9h,pance of the disorder shown in the pedigree chart is X-linked recessive and not autosomal recessifqgz :y f 0vd)phz,/9mve?

  Different species of living organisms have different n gfz5wq h)u9sg3k w,d(umbers of genes characteristic to them. The table shows the estimated number of geqf d9 ws,)gh(3k5gzwunes 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, inclufsbs;b(ziuwf - *)p-: no8ke69f qdecding flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rue*opf: bk seuf;fs 6 nw8d9iz q--cb()les of Mendelian genetics, which of these statements was correct?

  A biological male with hv) a599 omjydlemophilia and a biological female without hemophilia have a daughter without hemophilia. What are the possible genotyoy)m v9lad j59pes of the daughter?

  A dihybrid cross was carried out betweenp6rc7jj g6mm 9 two sunflower plants (Helianthus annuus) to sem6r96g cjmp7 je 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 indicate?

1.Explain how parents with blood type A and blood type B can have a;g89 x*oxq lb/jun b(+7ihvvk child with blood t/bubx9 v*+hxo 8nqkli 7gv (j;ype O.

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

3.Explain the role of inheritance in genetic diseases.