A man and a woman have a daug74q +kgnvf, hu bb/ o9oti9fe:hter and a son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypebq fu7n4 ieb9h /to:,o9fkg v+s could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a soma-z-q79 hy vobk uv. lnh/;z*nxtic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the r04 ei3mluk:mvesult of a c m3lmv:0i4uke ross between 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 matchedufn0 .dr.qw co )() ( daw9uf+ba6;*fceoeurr to the correct definition?

  Which of these statements is a correigp; k.qwpjhb(7g :qj b:cm:5ct definition for a gene?

  The diagram shows a pair of homologous c4ii7v:z o vv*q)hp5kwhromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crosse jw um-8xd6c5z2a dol)d in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting from this 8dmo-jx6cudalz) 52wcross?

  In some animals, the agouti allele cause jv 6wxt/*iw,76 wwazrs individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are hetirtx6w jw 7 w*vw/az6,erozygous 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 pe0j9- d4vtvwdua plants was either round or wrinkled. The results of an experimendju w09-v dvt4tal cross yielded 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 melanogao(uv 5ltf29 -7suh uaoster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of7tfhu5u (a9uv2 oo-ls a fruit fly?

  When does the random orientation of homolo c( bi6*x1iph-6rt4v g:ajdr dgous chromosome pairs occur?

The majority of the genes in the human genome have already been maywq -*:gmk3kd/t4sz*lz n ,fw pped, meaning the exact locations of the genes on chrok*n-yk g3mf 4zwtlsz, *dw:q /mosomes 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 correct d;fc;q5n7cdd26j;7v hduwhm qefinition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norv3 tck/zmj.6m regicus). Which arrow is p.m/3mkrtcz6j ointing to a pair of autosomes?

  Mendel observed that there are two possible variations of flower covhc5-oxvb p0 /l wwj 10(gt+tolour in pea plants, purple and white. Aftebphxoc lj0tw- w1(+g5v0 /t ovr 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 cf sanc, msbp8ojc. gnj2e 3)rs f*/bnd:,.v2d hildren born in London in 1991. sjab scfo ,nr. nb,dpcf2j. 8n* ):sme2gv/d 3

  Which of these traits is an example4ffi(qtuh , x) of continuous variation?

  Which row correctly describes go hvvg8w2+t 2;m8 eqmdiploid and haploid cells in humans?

  The following table shows the diploid chromosome number:j wnet-brb5/ usorpi54 io): of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is causmky+i3s 5tq e8ed by 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 a child w* n9bb ue82,wey*uy/m)mvo keith blood type O. What are the possible genotypes of the biolove m9w8,k2 )yuobu e *e*/mybngical father?

  Which row shows the correct annotation of the alleles for g4 kb 3wqg/9/9. ssiudeaat1 dblood groups?

  Which of these statements are true for allyq:8rql7o8 bwq/km s3eles?
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 incid c* gml h,eql .h6q2 (l.0d+hb-mdtrabence of sickle cell anaemia and the spread of malaria across the contine-6t2rm .hlealbb+hm*h, dg. dc0 q(lq nt 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 determined by a num9 b3ozen 4bdx2ber of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is domxdbo z4 3bn2e9inant 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 betweeip1 6wq u :,fe1b98 ft,juflifn linked and unlinked genes.

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

Sickle cell anaemia il w,qb9yd 4p.ss 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 skt, 8j oq7z 0/s:+ahn1fb2o sdqy q7zmale cat that is homozygous for brown, long hair 2yo hk j s/7 a1zq+780nfdqozbs,q :tsand a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped seeds (u)+)ynmsi (j g87blmsD) is dominant over oval-shaped seeds (d) and the allele fogb) +m)si(8ymnu7s ljr 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 hadh1fvaq* f*1y ir (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A t**df qvy1h 1afest 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 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 :rlghsqov1 2 4pedigree chartv olhqs2g1:r 4 below?

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

  Which of these statements about genetic disorders is/are corrs r;p v .)k tjtc+1j+z3:ao2zbo+ewatect?

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 polygenjx, 2wp01rxs;kue,lt ic traits can 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 inheritan4a2 3nyy3tc9izg 3pd fce of the disorder shown in the pedigree chart is X-linked recaf43icgy323d zyt np9essive and not autosomal recessive?

  Different species of living organisms have differ d*/ep ;u3lrgo2qy:hqent numbers of genes characteristic to them. The tabledp2l ge:q/ r;*yohq 3u 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 plants, including flower colour. If+8cr.;c f7 annkmgw+ xa)szu6w)l h*y the pea plants Mendel was studying can only ).lwynhgwu caazx) +sc+7r ;m6*f8n kbe white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia an;s r z 685sq;tcyoh;rpd a biological female without hemophilia have a das;p8c56soh;rz yr; qtughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out betw *d:(hdz*ekkmeq1 eq2+f0cyieen two sunflower plants (Helianthus annuus) te 1qe y+* dfze20h(mq:i*cdkko 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 indicate?

1.Explain how parentsr /ot*s8p.b eg with blood type A and blood type B can have a child with blood type *bte.8 gpros/ O.

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

3.Explain the role of inheritance in genetic diseases.