A man and a woman have a daughter andt:s(r2o 57 j v7tdqbud a son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correstq (5vb27od 7 d:jrutct for the biological mother?

  Which diagram shows the sex chromosomes of a somati te2mm, lixtjc -a,84fc cell in a human male?

  There are two alleles forj,n39a q5wbip flower colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and q 3p9j,n5a iwbpink flowers. Which is the most likely explanation for this observation?

  Which keyword is matc-.3;sgjryr djhed to the correct definition?

  Which of these statements is a correct definition for ;6ena2w2d xi ya gene?

  The diagram shows a pair of homologous chromeheo5:y / 7disa:pyb.osomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were cs:e09mg /m gz91cu ; eoz:revfrossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting from g9f: vzgo19ser;m/mz e0u : cethis cross?

  In some animals, the agouti allele ca7i y(,g xgr(oeuses individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs with eo7gx(gy ri, (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 eithergmopo**awae )/s n ;w0 round or wrinkled. The results of an experimental cros* gn;am w/*ow0aeos) ps 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 melanogaster) have 8 chrokmx;07 f vje8hmosomes. How many chromosomes are in a fertilised oocyte of a fr8mxfv ;7 kejh0uit fly?

  When does the random orientation of homologous chromosome pairs occur?3.dv +c2j/ mnamr/li( ppnqi,

The majority of the genes in the human genome have already been mappeiw2d7l su1y; 8s.l(+ xy0mkrnd9jl zqd, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of chromor(0 skjqi .lwd;ylldx n1792y+ums 8zsomes.

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 linked gen(dro fqd+; .v0oiif03qg j .p0c.fskkes?

  The diagram shows a v7 zkj/p 2/uvqkaryogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosomes2ku/zpv/ q 7vj?

  Mendel observed that there are juvgi)+*/puafm( w v1two possible variations of flower colour in pea plants, purple and white. uu* a/w im1( vjpf+)vgAfter 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 weigaq- p d/eq/k5iht of children born in London in 1991ie5q paqd -k//.

  Which of these traits is an example of continuorz+*5mm nbx uja9fo-,us variation?

  Which row correctly describes diploid and haploid ce/+4gnn irw.fv 2mz pk(lls in humans?

  The following table shows the diploid chi1l5 z ni*sa6xromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (4hd16o8a8vmuj je0yjs c*2 7ojsl7cgHb$^S$). 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 thk r)wek g il:: b(11;llvkku:ype O. What are the possible genotypes of the biologic k1hwev;(kl):1 lg :lkb:ikural father?

  Which row shows the correct annotation of the alleles for bloodmm-u:ogeq b ,5ioes: ; groups?

  Which of these statements are tr /wgj:aafdpcu;r9 2u)ue 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 of ma t7q 6hry. hukh0)cq/glaria across the continent o/y. qg ) qkcht0h7rh6uf 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 number of(-jl sy* ahmzc:i8g *ol8pvz- genes. Brown colour (B) is domy-gi*z (8p jlov8cmhz-* : aslinant to sandy colour (b) and an 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 unlinked genesv3mq/l fp* j8t9zqjqyc4)qvr1 u9 -bt.

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

Sickle cell anaemia i7tnw7zk/ (hb hs 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 that is homozygob c-yu)1inzz x3)d3u34 llocbk:com +us for brown, long hair and a female cat that has blacou bz u)34 -cbdl1 y)3mxcznc3l:ko+ik, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped seeds (D)jzq2 3euxlwk9p1 (ij. is dominant over oval-shaped seeds (d) and the allele for 2 3uxiep(lzkj wj 1q9.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), ak;tkl3) e ee9z7 zg*jxnd 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 shze9el *;k e)j37g zxtkort, 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 t+r+conr uyku**v3 v3in the pedigree chart bero ktvu y3*u3cr*n ++vlow?

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

  Which of these statements about genetic diso sgsgvjnjw6d u ez 7+.:kn-x70rders 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 showkf3w(h,ncl u li 0(tm8 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 disorj / jiopzu*5+lder shown in the pedigree chart is X-linked recessive and not a i5* /j+lzupojutosomal recessive?

  Different species of living orgek0s zda7 6c n98r:dqqanisms have different numbers of genes characteristic to them. The table shows the estimated 7enz6qk:9dcs dr 0a8qnumber 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 flo xfx0y o2nm21pwer colour. If the pea plants Mendel was studying can only be white or purple and follow the rules1y2n02foxx p m of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female wi 6fcg9ei( s)svthout hemophilia have a daughter without hemophilia. What are the possible genotypes of the daugh(vifc)g96e s ster?

  A dihybrid cross was carried out between two sunflower plantx1tbaj v 69bx:s (Helianthus annuus) to see if the genes for seed number and seexv61:j ba9 btxd 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 Bz+ jgrjo0u*4h can have a child with blood zjrh+4og *u0 jtype O.

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

3.Explain the role of inheritance in genetic diseases.