A man and a woman have a daughter and a son. Their daughter has normal vision,gmnw4:0r1x k u but their son is colourblind. Which one of these genotypes could be correct for t4 uwrmgxkn0 :1he biological mother?

  Which diagram shows the sex chromosomes of ayhj jx3msip 9v j4l,4kfegu1sy3* ak 1k8o ;u0 somatic cell in a human male?

  There are two alleles for flowti h4m;o-iwb/r-1joner colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring wioh/i-i1 m-or; njwb4t th three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched8i *0fp,ss iz3peacn: to the correct definition?

  Which of these statements is a correct definition for a p6 o1g9twq;zc)it u j.gene?

  The diagram shows a pair of homologoq/ yx;blo g93mus chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, y1h mjr6de c( p2kfh,7were crossed in an experiment. Which row shows the expected phenotyp7fpk61rj(2ed chy h,mic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairsbx ot hc:o0t*, to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are hettcxhb0o :,o*terozygous 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 ke1;0 r 9nlu/wxdu2w,s6dgsiej6;h*pz mz d +round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds andu*deluk ;nw9 s/dj zx ,hg2p06rdswme+z 6i1 ; 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)9mnwx ukx ;:d* have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fruit *wnx d;:k9xmu fly?

  When does the random orientation of homologous chrom7(uqr;y.vynp .g k,zi- jk+ ncosome pairs occur?

The majority of the genes in the rzn/*ys j:ot; human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of chromosome;toj :zr*y /nss.

1.Define locus.

2.Identify the number of loci shown in the diagram.

3.Distinguish between gene, allele, and locus.

  Which is the correct defingz1sw ;qe:hzi6 i3b/aition of linked genes?

  The diagram shows a karywk5rem r 2 tp;/has0f5ogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair o05reh;s /wfpt r m2a5kf autosomes?

  Mendel observed that there are two pos*t0rgm,fr,;zl (hhjqsible variations of flower 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 j(r;zfr ,mglhtq ,*h0were the genotypes of the parents?

  The graph shows the frequency of birth weight of children born in London in 199l2j1.hpmb8(u+lht d3f r v tk(1.rkbf3 dmh +pj2u.tt18 vl (h(l

  Which of these traits is an example of continuous vae.xf uxa9w u.)riation?

  Which row correctly describ 2:o8c4x zi57fs(x3dp1 lnaekqfhv: v es diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of specf) v/kij-.qbcies.

Which of these statements is correct?

  Sickle cell anaemia is c;kuz; na4 vox.aused 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 ba23 ja1uonl zr 1/c/rqlood type A had a child with blood type O. What are the possible genotypes of the biological fatherqn3u aj rl2/a1/ 1zcor?

  Which row shows the correct y+e8k49v u cec3kvkp.annotation of the alleles for blood groups?

  Which of these statemenej:r.v i664ct7 flp dxts 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 incidenceda 0 uiojb:7-q p3h/ze of sickle cell anaemia and the spread of malaria across the contin3dqe /zhi :o jpb70-auent 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 przewalsb-2k*kret(cw ;r1nc r8vkw) okii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to one t8(2r*wnrrk)ov c-b1k kw;c e 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 between25 tkpoup r bij387g+7l6ditr68jeql linked and unlinked genes.

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

Sickle cell anaemia is ca)1 9xczyl-f jig)a0+(vja4ofa 2 lrxx used 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 homozygous for b;6*ucbvh09s k b.j+t.heg b awf1+deo rown, long hair and a female cat that has black, short ha6 e. aoguv;+ .9*kejbcbwsf0h 1bt+dhir.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped seeds (D) mdw0+;f w vats7.w 9v;ane wc;is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short seeds (law mec9 .;nws 7d+v0vwa;w;ft).

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 voq:vn/x)+g;stvjz o-4 a+sohair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carries jta n zvq)voo:-4s++vx/og;d 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 shok1d:o 9ut )5q kf 3enz0biz8i5f5w2ob mnaxc)wn in the pedigree chart x0zaft bfe9o5: oi8cb2ikk5) m1 wunq)d3n5 z below?

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

  Which of these statemen*ty8teq2n ihqxlc*1ha) n.o 2genf;bb ka82* ts 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 cavz d b..u,d qo8 j8bokehyew, u)ndsi-b( *4;rn 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 tx2s 2/wlu poy3he disorder shown in the pedigree chart is X-linked recessive and not autosomwplo2 x3 s2y/ual recessive?

  Different species of living organisms have diff781o6 w -jvsfy/ ldx/(bmo z3r fpro/ferent numbers of genes characteristic to them. The table s po763 -1bf (/l vm/xyosr zfodjr/fw8hows 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 clwk,jf4q. 4 *z70f v igzgv0teharacteristics of pea plants, including flower colour. If thzjiz*e0g,g4l 0wvvtfkfq 7 4 .e pea plants Mendel 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 hemophilia and a biological female without bywc/z .lufx.)pc1n6 hemophilia have a daughter without hemophilia. What arc6uw n y 1)/.fplzbcx.e the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annuu )jc x /+34o:jqtovolrq0i:jis) to see if the genes for seed number and seed shape are linked. The critical value for the chi-squared tescoo+:r/ jl 0j j:q 3x4v)iqtoit 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 B can have a child with bw9 jw;s5 (g ;d(yyz*mknlez-qloodde-;9qjl( zzm ;s* gknyw5(wy type O.

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

3.Explain the role of inheritance in genetic diseases.