A man and a woman have a daughter and a son. Their daughter has normal via :u ,uhz t.a1n v9 0+7rjhl2ds.eilexsion, but their son is colourblind. Which one of these genotypes could be correct for 1d hn,2iuz.reellxvuah jt. +:a907sthe biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human male? epf(r2p s4c z-t f6*ld

  There are two alleles for flower colour in snapdragons. However, the resu*h25evhz ttr1l4lm -clt of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the -5 2elt4tmh lvz*hrc1 most likely explanation for this observation?

  Which keyword is matched to tis+x3erx,*w a0 htc:v he correct definition?

  Which of these statements is a correct det gng. h)p 64dvil8v)m, fj2ygfinition for a gene?

  The diagram shows a paitdaw.b1 tu u..r of homologous chromosomes.

How many loci are shown?

  Two individuals, hetl+ hc )yhsn)8+lx ded1erozygous for a specific trait, were crossed in an experiment. Whley +s+ )dh1cl)nxh8dich row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to havef zurh.k;b76v a banded pattern. The non-agouti allele causes hairs to be a sinh7 zv6kf.u ;rbgle 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 plants wasgvm.wxvfv ; 22 either round or wrinkled. The results of an experimental cross yielm2x.gvv2 ; fvwded 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 (Drosophila melanogaster) have 8 chrovw4(1no,xr ow mosomes. How many chromosomes are in a fertilised oocyte of a fruit fly?4r1onww( ,xov

  When does the random orientati: 0k; 1vhvoh3j 4qwhecqbdi66on of homologous chromosome pairs occur?

The majority of the genes in the human genome have already )dh4v3fj q 3sw,b 14 h yumo4kqk-pg,gbeen mapped, meaning the exact locations of the genes on chromosomes are known. The du)w pgf v3o qyk1md3gk-q,s4h4b,j 4hiagram 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 correct8 gyng06/p ojh definition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norlh cnv.cqp;.a9ycx2 :mn ) poyw8y j)+vegicus). Which arrow is pointing to a pair of+ y.cmnpqo lpaxh) 2)89:;wy .vjc cyn autosomes?

  Mendel observed that there are two possible variations of fli7:+ ba5jzyqiower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1. What were the genotypes of thej5: +a7byqzii parents?

  The graph shows the fre :hc9 g2awltf88bu*fh3;q x iiquency of birth weight of children born in London in 1991. i89tug;* cfqf l:a8xh hb2i3w

  Which of these traits is j.,q.4f/4fp 1mskqgjaex r a7 an example of continuous variation?

  Which row correctly describes diploid and haploid cells in humans3l7ib hp4j:x u?

  The following table shows the diploid chrtgvq,s hvx)5* omosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by y g6y uzxk85 r0dnd e-4ew+qq/a recessive 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- xe2xj-3q4wu1cu c0k+rz yhm a child with blood type O. What are the possible genotypes of the biologi mr- xyh1qx 4 e2kw0zu3-c+jcucal father?

  Which row shows the c/si(lnw p32jgorrect annotation of the alleles for blood groups?

  Which of these stateme3 tusw0d 1d,lonts 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 atlh3vdm jo;3 2hwgz5 1nd the spread of malaria across the continent of Africhgh5zl2 ovd1t 33 m;jwa.


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 determined by a numbojm tzx-2b (ki3 n+xl4er of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominantoz3mx-kji4tb lxn 2( + 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 an8o y 4uk.xnzl.d unlinked genes.

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

Sickle cell anaemia is ca 8.k)omo6sod aused 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 gn,bghb f(xi4 tn*mh:w8 /4)j kn/xxfthat is homozygous for brown, long hair and a female cat that has black, short haibjxxgwf/) f4n,n hkig8 bxt(/ n:mh*4r.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diams l pm7b:-vvdko.0 n2mond-shaped seeds (D) is dominant over oval-shaped see.:d-ok bsv2 vpln7m0mds (d) and 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 (l), xq.bq zos*v ;ex a8,k4and 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 andkz* e4xqx s8;v. ,bqao 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 cq ;zfgo2 zygks9tp 2+,hart po9kzstq fg22g y,+z ;below?

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

  Which of these statementsdzlo2:cn hp2o l1ty +; 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 2kokg2a ,l)sc7kg4ttpat+uhlgn7 3.0p x rv1 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 the inheritance of the do,tgin+ ,x oi- (r)dcwisorder shown in the pedigree chart is X-o d xon (i)rc,-twi,g+linked recessive and not autosomal recessive?

  Different species of living organisms have differenl9 rxj: mxcux1xh6.+w t numbers of genes characteristic to them. The table +.xxlu1 wc9rmx6 h:xjshows 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 peaa3q(wv/u vce 6 plants, including flower colour. If the pea plants Mendel was studying can only(waue 3v/q 6cv be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female/0ihgqp es+zu) a/o 1v without hemophilia have a daughter without hemophilipoz a)hie vu/qg +0/1sa. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helia6ewtp -jm43z v7og2qtnthus annuus) to see if the genes for seed number and seed sp t ztw73o2em v64gj-qhape 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 0avza i +-f:glblood type A and blood type B can have a child with blood type O. a- g0 lza+vi:f

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

3.Explain the role of inheritance in genetic diseases.