A man and a woman have a daughter and aj+ 6+8ivlb) m:ek u ic6ofhi6iuhh*p 9 son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct p)j8m+h9u *i oh:e +h iiku6v6l cib6ffor the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a +mzw/mw 1 fwny 4b9br p,;sj0khuman male?

  There are two alleles for flower colour in snapdragons. Hoks2 (u3331msq tfabhm9e bjb 9wever, 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 explan(3jbk m um92qbtas b9133 hesfation for this observation?

  Which keyword is matched to the corren9(tss ew8:yzct definition?

  Which of these statemel6 jdxta7+k i,nts is a correct definition for a gene?

  The diagram shows a pair of homologou9o 92triamsb.s chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed o+ k8q)gxopy msl/p p4h-8xc 06o km3ein an experiment. Which row shows the expected phenotypic ratios of the offspring resulting from 0o4pmpps-ok eqcox kx+m3 88l6)/gh ythis cross?

  In some animals, the agouti gcy(c0r zbh uy0 h-7g5allele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who ahc gz- y70gb05 huycr(re 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 8+yx.nei vjb; round or wrinkled. The results of an experimental cross yielded 315 offspring with rou. xyi8j+ ;nebvnd 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) havemlzn6kt ;xk d1rjjvbq*,1e 2 4 8 chromosomes. How many chromosomes are in ajj* r1e;xq d,k b12nlv6mtk4z fertilised oocyte of a fruit fly?

  When does the random orientatio( b2n (;ek-tgh)me rpayeclo42 t(ve 5n of homologous chromosome pairs occur?

The majority of the genes in the humangl9b9ee6 /gm1q :u4d mht )loa genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation d4e)91 a gl/ mlb u6qte9mgoh: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 defin:up,(dd,62x4z prklp7c xfi jition of linked genes?

  The diagram shows a karyogram oft 8 ag722nsgnr a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of n rsg t2n72g8aautosomes?

  Mendel observed that there are two possible variations of flower colour inrlipzkr:sb (f9zlvc:a :i( 98 pea plants, purple and white. After a genetic cross, the ratio of plants :p:(8:9 cksv ibf llr9(arizz 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 chh6(ew4med+ :;yb c kueildren born in London in 1991mbyk:eu(c4dhe6 w+; e.

  Which of these traits is an exaex9o , h, n1 al:6iy8z36qbb*caajjf qmple of continuous variation?

  Which row correctly describes diploid and ha./c:itz i)zefd i.j x7ploid cells in humans?

  The following table shows the diploid chromosome number of a range gvz2x0zahp; 4qu4o c.of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive al -j jv 23ov(cp p1f8.7vltbytxlele (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 bl(fuq 5 h:(n1l1og)8grli*lc zb9 xa nfood type A had a child with blood type O. What are the possible genotypes of the biological lfa9zlnlbho8xggc *:511 f( r)inuq(father?

  Which row shows the correct annotation jgf1m+pghft qg3 7j( ee,neh14h q( x+of the alleles for blood groups?

  Which of these statements are true for allbl59s3 sq( g:x; 4bv xcwjds/keles?
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 sx+xr-j io4u pyr3 zm92pread of malaria across thu4z 9 r23pox+rijym-xe 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), te(-.6wrno9u bgp e/n 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 domienbn -u 9w(. per6o/gtnant 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 genes. zgfs+9(ka u (e

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

Sickle cell anaemia is caused by the vy4i.z;:vnw q 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 az vom+ft d mv;u 5u;v0ca/,9z bc2*pscross between a male cat that is homozygous for brown, long hair and a f0dc/ +*pm5bf2z cvaz,sum ;v;9oavt u emale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the alleldv7s1zy45 vc7 a4 pe.qcff7wqe for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (Lcfwapf4v.cdv qsz1qe7 775y4 ) 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 domik 0 uzp oi0l5a,w5y.tuoo mf*n7t,i-lnant 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 p.0k fzlwi 0 mtan*t5 u y-poul5,io,o7igs 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 inheritan n0du , w:8qq8t k5sdbzid+/txce of the condition shown in the pedigree chart bewt bq/ sd0: uq8 +nztddi58kx,low?

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

  Which of these statements about genetic disorder;,brlmr qbtqvkh0 54 *tc8kr* s 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 0 1-e8vifmal eendq 1mu.vl 7ax;;g c/distribution.

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 -/vfyrrxjn /m-o 8v-mmm kr 7.in the pedigree chart is X-linked recessive and not aj.o/ v8 m-mfrrm nv-rx7/mk -yutosomal recessive?

  Different species of living organisms have differf/iungnu8 v5f4 6fy/pent numbers of genes characterifi8 nn fgf45// u6pvuystic to them. The table 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 plantszm 5 cb-is9/awv x*pdsz 33t+j, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genc tipv5wz*/- xs 9zadmj 3s3+betics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophilia hak;-neb p7yj5g xq/qt2ve a daughter without hemophilia. What are the possible genotypes of the dauyqxgp5e;-2k 7 qtnb/ jghter?

  A dihybrid cross was carrie imnpiqq/u v539bxd 84d out between 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 wasd b xq3umqvpni8 9/5i4 7.82. The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parentsjs 8zrla;.i6.k pbq2 q with blood type A and blood type B can have a child with bl.;r.q826s bp jaqli kzood type O.

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

3.Explain the role of inheritance in genetic diseases.