A man and a woman have a daughter and a son. Their daughter has normal visin d:u ok8v, m:,twf d.,kxo5pion, but their son is colourblind. Which one of these genotyp8 kp:,xw .dtoif5 m,:vnk,u odes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a huw.wf9o(ey vk7man male?

  There are two alleles for flower colour in s4u7;y dvn 6:segqqw 0cnapdragons. However, 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 likelyn;g70dq4w6 cq : sevuy explanation for this observation?

  Which keyword is matched to the c spc /isw: qk- q8* ijtm,-mek.r;0iplorrect definition?

  Which of these statements is a correct definition for u0b. s6icfqnu m8rg/+z-f y4i a gene?

  The diagram shows a pair of homologous chromosom6jt t mys 0hrh1 p729aqd*.bjxes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed coly88g(,ohwd b( t.j in an experiment. Which row shows the expected phenotyowhdt., ylo bj( 8c8g(pic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a h 8*uo byjpnf+i0 p+m;banded pattern. Thyf+0bpu* p;i8+n jmhoe non-agouti allele causes 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 plants was either rwn55:hfa oha :hvic7) 1ni(b jound or wrinkled. The results of an experimentalb5vfh:nn :jc7hoa)w ( 1iih5a 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 (Drosophia76: 5ymo jrtmg/j0fjla melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fruit flj g/6a5mj:f mj7r0 toyy?

  When does the random orientatios3pl5;nhb0n q bkc5z :n of homologous chromosome pairs occur?

The majority of the genes in the human genome have already beeh;zo7yfsq hs+ p8 0z3x:*nph on mapped, meaning the exact locations of the genes on chromosomes are known.qsnfh +*o:p hxzs3z;0 87poyh 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 definition of linkwcflm.7lutaxb;) ,5a-. fwm svga4z z6.hpj2 ed genes?

  The diagram shows a karyogram of a brown male rat (Ratt:094: bdhp 0iw2)ptwk9t g rrifjuwf3us norvegicus). Which arrow is point0t9f9w:rp:0wikup4rjgf2) i ht dw3bing to a pair of autosomes?

  Mendel observed that there are two possible variations of flowerswi.uh:w*gc2 colour in pea plants, phwi:2cu*gw .s urple and white. After 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 jub::.)ps,ffkafm 2i of children born in London in 1991. :jimsp fb)a,uk2:f. f

  Which of these traits i o+h a2+ox*lngs an example of continuous variation?

  Which row correctly describes diploid and haploid cells n3d)ifjq8 gsd ,ya9e. in humans?

  The following table shows the diploid chryg0fqlsbnc;r3v8e a ; w694d msc(0t lomosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a reces t8k fzvbw,)osq;oj9c h0j4p2sive 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 with blood type O. What are tfu+(ylio*9wkxh1lrq 18 k/ ah he poss1(9khlah lkw8 y+x*qi /ruof 1ible genotypes of the biological father?

  Which row shows the correct annotation of the ax/2fvsia igiuf0 q9:-lleles for blood groups?

  Which of these statements are true for allelekcoyx 3 1ju,juy4g 5(zs?
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 ofe,ndcy3gxejg87 s+t 9 sickle cell anaemia and the spread of malaria across the continen gde7c 83tn jg9es,x+yt 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 number of xrqjkd*)- k)t genes. Br )q*xtr-)k dkjown colour (B) is dominant 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 unlinkedrml/g+ 9lfk f ,33)qbxrsnvi8 genes.

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

Sickle cell anaemia is caused by the allelcffb d3jv z1yp 2cwkr*+ )9(cve 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 sdtg del:wa2/93kfk4fsjl 6kd)g7( t between a male cat that is homozygous for brown, long hair and a female cat that has black, shortgk: j 3w7dfl)sf9ktde6 g( as d2/4ktl hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamon h(1jr18wje8no obco2d-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over shortw28r(cj on oeh ob1j81 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 ho0 fes,p3wy-yt-;gg, 3a9xxl7 g izivair (L) is dominant 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 pigs and female short, straight-haired guinea pigs and a chi-squared test (χ2) was carried out on the offspril-s 9vfox gy,tix3i 0g;gw a y,z3p-7eng.



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 :b8:tckld6n ud a9g6yof the condition shown in the pedigree chart beg t66ld8nudk:acy: 9b low?

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

  Which of these statements about genetic disorders is/are correcst+kq)+ 4mixv77j09nth bvo u t?

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 norm k;o4buzf 1v5nal 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 in tcx4na-u.rm rdl :km( *he pedigree chart is al u(r4cn* mx.rkd-:m X-linked recessive and not autosomal recessive?

  Different species ofz ljrmgf c/9)29 htqkx9pmd7/ living organisms have different numbers of genes characteristic to tk9tzgrlxd m //j 9c97qp)hm2fhem. 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 plants, including flower colour1+yxze+m od 6geweapg*/0 qw;. If the pea plants Mendel was studying can only be whia0eye+oq *;zwpegm+dx6 1/g w te or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female wit hx1 duj)pp4a7hout hemophilia have )pd7uj4x 1ph aa daughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carrie-b+vradw4 d 3ld 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 was 7.82. The calculavdlb -+4wr 3adted value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A and blood type B can have a child wit..:pgd2y pzic h blood type O.c p.2 gz.ypd:i

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

3.Explain the role of inheritance in genetic diseases.