A man and a woman have av/ u:jz0m9i isc: k9fn daughter and a son. Their daughter has normal vision, but:vf9/i unckz s:0ji 9m their son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the hqdx+i 5spol p)5wv +6tc g--hsex chromosomes of a somatic cell in a human male?

  There are two alleles for tfyr azrp40+.flower colour in snapdragons. 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 likely explanation for yrf+.pa4r0 zt this observation?

  Which keyword is matched to the correct definition?45 ,kdkgy mpr*

  Which of these statements is a correct definition fo11ob7;ld;w cqm bhq/qr a gene?

  The diagram shows a pair of homologous chromosomes.kxqf* qju*5ste l;: i3

How many loci are shown?

  Two individuals, heterozygous for a specific i/g3ni.zks -qd )zu+v trait, were crossed in an experiment. Which row shows the expected phenotypic rat ik). zngiu+-sd/ 3qvzios of the offspring resulting from this cross?

  In some animals, the agouti allele causes indl my0 q)jaddwth,r +-:ividual hairs to have a banded pattern. The non-agouti0 +t)hm,ld:-qyr wja d 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 irpsc7aqn;9 a7 w/kk .andividual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrp sqn9k.rc;w7 /aak a7inkled seeds.

Which row in the table below states the most likely genotypes of the parents?

  Neurons of the fruit fly i +zp56,7qawtpa ;t v1/oaa*pxew9 tk(Drosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertili97aw ta;p6 x kwa5 ozt1tv p/+eaqp*,ised oocyte of a fruit fly?

  When does the random orienta7(1rf-xksw)vw : c7l2fanfpkb ;/ 4r fclxvy1tion of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mappedg,w8jw6c)h+ e pjx;fv, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of chromosom w);8 fhpjc,gwx6 +ejves.

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 4 xmwn,z2j *7: uwneqhof linked genes?

  The diagram shows a kau 3aiq71 z;v7grgvxt.w.it5eryogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a v. gi7 t5e31gau;qzi w7 r.txvpair of autosomes?

  Mendel observed that there are two possible variations of 5f3*x91aed c fru.xv,m 1fktxflower 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 were the genotypes of3kavfu1 9*x efr.5fm ,xxdtc1 the parents?

  The graph shows the fre e+0nj9x )palpquency of birth weight of children born in London in 1991. ljpp9x )ne0a+

  Which of these traits is an example of continuous rojl gc19lh-*b4 d ,mevariation?

  Which row correctly describes diploid and haploid cells izg.77gri 2s ukn humans?

  The following table shows the diploid chromosome number of ajcx54m7ca9z jqpu*(o lbkw*, range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a -vcv ze ggro+868z9 )d i iwfu+a(v* p;jf1nrcrecessive 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 typq0ay- +jkgx f x+)x)hve A had a child with blood type O. What are the possible genotypes +f)v+-x ky0 jhqxxga)of the biological father?

  Which row shows the correct a.itc1i7oy0l:bt tez, h za, )innotation of the alleles for blood groups?

  Which of these statemevpu p caoae4vcm9zhmh v;e)u ((7884fnts 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 incidence of sickle cell anaemia and the spread of malag( c+ :hf0 ywalxq i2 a*9ihtv6,vie.iria across the continentei( *tc2aiq ,6v9xyw ghi:i0lfh.va+ 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 determinm oenwuzjm pa8;3:c5y:3:aqyed by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour ;q::ya 3 ewocym 5jaumnp8z:3(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 unl 8ej1 hus /8xvzzz9m9pinked genes.

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

Sickle cell anaemia is caused by the allele Hbkn8. g n975r 1d7d ysa:lpkuci$^S$ . 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 crd .yd+* ; a*mknk)aip j0qns8loss between a male cat that is homozygous for brown, long hair and a femaa0s*qydj8 ik d.alm ;+k)pnn*le cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum offihy bjndh: *:j1m0z,rscinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is domin*:0 b hr1mdsjj:hyn,zant 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 porcf oaw2c)3g,fu ellus), long hair (L) is dominant to short hair (l), and curuf)gc of3aw ,2ly 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 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 condo:.c5g,grot 5ex va 5mition shown in the pedigree chart belowmoxgrcvt5a g55,e o:.?

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

  Which of these statements about genetic disorders iska-:93id w1agdpjui 572mysn raw88e/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 polyge9nmp ur,n35+s/ug a0ga fkw,mnic 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 inheritance of the disorder showi r x0hooa6(d2. pz+pr a25zbmn in the pedigree chart is X-linked recessive and not autosomal recpzohra2.x da+mr2 6 5i0 bz(opessive?

  Different species of lkrqgp*+k(q h jkhy pgzgp2i*nyg7fj 1- g.7.9 iving organisms have different numbers of genes characterigj hz rgpnh*q +k2j*fy.kp g( gk71 qpig97y-.stic to them. 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 *)8 hv*2 7l(fxm d foqesqnxb*colour. If the pea qfbhq* ) ds7xmle2 n(f*xo*v8plants 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 hemophjuhy g :mr2,(:7qywywilia have a daughter without hemophilia. What are the possible genotypes of th(::gryymy u7 wq, 2jhwe daughter?

  A dihybrid cross was carried out between two sunfl9 y .y 3gqnrm tjydt-;1dz5k:rm,cjp-ower 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 t,nzjr: c9kpmy -t 1t.ry5j3- gd; qymdhe 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 withw:5 stfe e+3mm obkh)n6 7e64l spmm0u blood type67ps: mseu hm6ew+)m0l4o3tmebf5nk O.

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

3.Explain the role of inheritance in genetic diseases.