A man and a woman have a daugpn uen 9j5.ek0hter and a son. Their daughter has normal vision, bu0ue 9p.en5k njt their son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human 1uvxl+; irkqr+ ow wz20dmq86male?

  There are two alleles for flower colour pzdr x tpf)1(n f--jn7in snapdragons. However, the result of a crossp)xz n j-rfpt1 -fd(n7 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 matcu-7h4tiv6z3 mfk h1hk hed to the correct definition?

  Which of these statements is aj tl pln-/:h4 vwq9gxoep1icj74fa .7 correct definition for a gene?

  The diagram shows a pair of homologous chromosome5 y/rog3i* wz*+cqh lcs.

How many loci are shown?

  Two individuals, heterozygous for apir:vj/cw a 4m7w1m*k specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting fro7wi mm4kcp ajw/v1r*:m this cross?

  In some animals, the agouti allele causes dk y//ghb p+t.individual hairs to have a banded pattern. The h+k/y /d b.ptgnon-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 rou5 c m9 pw1:v*dakl2xrhc1b:op nd or wrinkled. The results of an experimental cross yielded 315 offspring with 9hp:lpk w5cx 11:d*a romc2b vround 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) hav/ii6,;7ggotx,p(vie );lc 1 bmddp ige 8 chromosomes. How many chromosomes are in a fe,i/b ldx,o; pp7i(;i) v gmegdigt1 c6rtilised oocyte of a fruit fly?

  When does the random orientation of homologous chromos4 g 2kxe6rx0g -orn+unome pairs occur?

The majority of the genes in the human genome have already been mapped, me22 l pj m3c a v*zu,ye*q*b3xqfer*o+kaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologousfek*r2zmjyuel 3qb x *a2pq3+*o ,vc* 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 f,ryanc 5,2t klinked genes?

  The diagram shows a karyogram of a brown male rat (Rattus w8ukcr9(rdyb4vj m; 7- uo)rp8q-.jtirt7t fnorvegicus). Which arrow is pointing to a; p7tjk )icy8tm8uor 9 7(r rr.w vfdjb-tuq-4 pair of autosomes?

  Mendel observed that there are two possible variatb; q mvlp9c9w71n3y.ftv3 ezfions of flower colour in pea plants, purple and white. After a genetic cross, the ratzlqbye93 cvtwfn; 9 vmf.3p1 7io 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 children bornni8 so)k)dj7e in London in 1991j)keniod7 )s 8.

  Which of these traits is an examol9hs5sf) m)t+o fpv9ple of continuous variation?

  Which row correctly describes diploid and haploid cells in uwis-o:i,7z*6 l zivuhumans?

  The following table shows the diploid chromosome numj)d+1vxw 0knvl 9 lqq8ber of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused xe v )en 6)9yxodgwr;.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 with blood t l+ bua* 4 ot)e-y.cds8kqa0r( gy,xfxype O. What are the possible genotypes of q-kc g, x srut8)e0 (*.yd+x foaay4lbthe biological father?

  Which row shows the correct annotatio3 l6c a-e 4otfcmsehb y;mr*)2n of the alleles for blood groups?

  Which of these statements are true for all5gom iek-tifvb 6/*j 5zs+:) ; v pvoxygoe9;beles?
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 aj)2 oewllvx4+o)o r-k naemia and the spread of malaria across the continent of Africa. v4rl)w-k+jx )oe2o ol


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 dk5 c *awi)/73at uisabetermined by a number of genes. Br/7b5ckw *ita)au3 isaown 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 uhh91 4i jppm ov9w/ue+nlinked genes.

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

Sickle cell anaemia is c7b ,yklhk 94dgaused 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 s y oh,ve* 4/5to8ivnzbetween a male cat that is homozygous for brown, long hair and a female cat that has black, short 8t z yi/o5n v*o4sevh,hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), e7;3 raxaw 2vgthe allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele forgae xaw;v3 27r 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), lonn xh psux;(syu59f:. wg hair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c).pu:w u .x yf5snhs(;x9 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 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 t ssls;8e)+ 1a inxhixjro /p( .fw/4yche pedigree chart b.4;j w8/f/si ocpansxs )hy +(lexi1 relow?

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

  Which of these statements about genetic dsj )2nd.pwp v);- ecmcisorders 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 axhhsdx:c(35 mm7) jcdistribution.

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 wm i,: c(rjfv;shown in the pedigree chart im;ri(jwc ,v f:s X-linked recessive and not autosomal recessive?

  Different species of living organisms have different numbers of genr 9e59 xiphuy5es characteristic to them. The table shows the estimated number of genes for five speciesuipr5e9 5h9yx.
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, inckt;es23go8r1br azb2c j ojm16fa*h/luding flower colour. If the pea plants Mehzr a1rb2j1mt68;bko 2 jo3*esgafc/ndel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hem t5nyi*p06j bfj7rb8tophilia and a biological female without hemophilia have a daughter without hemophilia. 7 rj60b fpt ib8yj*tn5What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower oo+g 2z*xqnj*8ck /vpplants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical value for the chi-squared nxcj/zv2o+*8qop g*ktest 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 iib:b dbibec 441.3eq4jh7x0 5mzx*z 9hfmq fB can have a child with blood tycxii0 dq:jzz.ehfbqmh1f ie4 3b 7b5b* xm4 49pe O.

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

3.Explain the role of inheritance in genetic diseases.