A man and a woman have a daughter and a son. Their daughter has normal visihgg5c2)kkm x m*6j3yuon, but their son is colourblind. Which one of these geyc5*m g2 mhj63gk)xku notypes could be correct for the biological mother?

  Which diagram shows the st3dydy ,0e5 wsex chromosomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the re- l 8mmr;u,kqssult of a cross bel,-rk mqsm8 u;tween two heterozygous plants yielded 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 definitionx0zu9zi 2ngmkws w0a35( ;y nm?

  Which of these statements is a hgp-p*ah+72 vt xthbmekp*+:correct definition for a gene?

  The diagram shows a pair of homologous chromy+dh60kgfv g 7wph q)5osomes.

How many loci are shown?

  Two individuals, heterozygous for a sp. 8 d6(et*me+jrowjot 51 cysiecific trait, were crossed in an experiment. Wyc*mer.i je(o wo86t1s+ 5djthich row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have 7rd0q334n8z gso r 1nve/kwh la banded pattern. The non-agouti allele causes/whzrne 87 4q3o1vdskr3 l n0g hairs 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 individual pea +ptq-knoa) n+plants was either round or wrinkled. The results of an experimental cross y-nq +o)a+pt nkielded 315 offspring 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 (Drosowuot0 9ue,kc4a/9bsvhm e5m ,phila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte ofc09ee4 /muskhba,to,m 5v w9u a fruit fly?

  When does the random orientation v7 vi,o5jv0m,0 ,cwsvipuneep.95zx of homologous chromosome pairs occur?

The majority of the genes in the human genome have 0wj:jb0ny5xo u1y ;c palready been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below wp 0n1c5y:oxj;y0bu jshows 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 li sxfg+xnb41 q yjhlis-xm5(yqar2 r9h,ur 9- )nked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norveh8ksmr7nd5r w1lq5yb8/p u.egicus). Which arrow is pointing to a pair of autosomwu rysb8 rm.5le q d5h18pnk/7es?

  Mendel observed that there are two possible vari);mbkz4pr w)m;0 aonk*jq 88e ktzwj /ations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple fl0)* nbmw/4ez)o8kkz kaj;q w8;jpmrtowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of chplt /4r8vm /whildren born in London in 1991.m//vr84htw pl

  Which of these traits is an example of continuous ydnni0q6 : (y.chjb9rvariation?

  Which row correctly describes diploid and emb . a5 s gpqvnnw94d-p.5ms9haploid cells in humans?

  The following table shows the diploid chromoq5 ab/ga rz:qfr+da (;some number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (n0mm hal4e13ljn *x)s 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 wi 5znr xq+jo1.kth blood type A had a child with blood type O. What are the possi z 5jxq+kno.1rble genotypes of the biological father?

  Which row shows the correct annotation of the alleles ;fxo*3j6qusk.6z rm9 o gjy a2for blood groups?

  Which of these statem1ipsuc+v7j5)zduk9 d oq /(vzents 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 the spread oq da0ed9 1d2; mx1dvjg ew8ki)f malaria across the cont20 dmj k;18 vided1dga)eqw 9xinent 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), fcu,tj bni2 ip18*gea* ur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and ap iaeti8c1* ugj,*b2nn 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 un r3f6 .cq-kqyehpuk+2linked genes.

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

Sickle cell anaemia is32,csywded r6 g/*qn u caused 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 cat ju+w gk5ln+4s 941bq loqwuc3that is homozygous for brown, long hair and a female cat that hll+q+wg3ok54 94n js wquc1b uas black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-s( y14nmtw5q(bh o4,oxgs il 3*dbwp2fhaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is 2t(mnf5 ,lbbiqy 3wp( 4*hws1 oo4 xdgdominant 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 shore)bv su9*j: ekt 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) was carried os:kbje9*u ) evut 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 pedi-6-6hzq a f)cgth r:zegree chart be:tacq)- 6hg6h ef-rzzlow?

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

  Which of these statements about genmgtz;tgs mx:iw07m 7 w3kx)3: kfv0wretic 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 distributiipuar vw*ml7-*x ce14on.

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 disorder shown in the pedigree t tp1kcet*)di/-yh4 qv1ex7yff4 4whchart is X-linked recessive and now 1 y4v4-exyekpt 4fhq1t/ f*c7hid)tt autosomal recessive?

  Different species of living organisms have different nu/xter 7n6/u2 d1tpnprsp + mh/mbers of genes characteristic to them. The table shows the estimated number of gen ///dprtte hmrn2x7n1 sp6 up+es 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 characteristew;ljw1c l6scoobsyj y :bn(xr6+ 56:ics of pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow xr 65e1 bw:l ly6njs+wob6c(j;co:sy the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a bio 3xmv3jq:*zlk logical female without hemophilia have a daughter without he x jm3v:qlk*3zmophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out betw+(yn :jqtdz,x9 jvm7neen two sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The criticalvjn,myx: 7q+dz t( j9n 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 3b8m r g)lk*agtype A and blood type B can have a child with blood typm3 k8g rb*ag)le O.

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

3.Explain the role of inheritance in genetic diseases.