A man and a woman have a daughter and a son. Their (fo(bow0m0 )au amduma1j 2 h6daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the oah a(wm o a )0j6bu2u0dmmf(1biological mother?

  Which diagram shows the sex chromos.6she66ks sqri8 gaz;x: wrg 6omes of a somatic cell in a human male?

  There are two alleles dcww g7mr ;eh)5icdb4 6 j 7dwnb1k+(tfor 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 this observd+k 4d7 1 w b;mer)7b ijtcwn(hg5d6cwation?

  Which keyword is matched to the correct definiuxgh1uz gu:zf8 ,.q*m tion?

  Which of these statements is a correct definitionnrc96la+e 0y1 ofva4,c6y pau:vj (gf for a gene?

  The diagram shows a pair of hk **orc wk3vpn z*wvg 68jqf7r cme):5omologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specif cpa1 pvf9,u4ha 56mboic trait, were crossed in an experiment. Which row shows the expected 6 v419uc5ofp m habpa,phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti x9u cu.8a psc;allele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous hav. s98uxapu cc;e 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 see0qjb gt3.5pj9 xu.fzu bpwbh : 3f,ef,/ai(cod shape in individual pea plants was either round or wrinkled. The results of an experimental cro.fg35 .9p,bbbhuc fj0 /3t(fqwoa ,pzex:i ujss 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 me4tv;nkr9g-(ck q,sej j 5c1 dulanogaster) have 8 chromosomes. How many chromosomes are in1,nsce v (-r5;cg9jkj4tqu dk a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous p.6bcv v,wf1c chromosome pairs occur?

The majority of the genes in the human genome have already been mapper55gbdk9h77ma6.zu h/3r) jy gsaqc 4z ;jrajd, meaning the jamzz)j d 5rrg;9s3/ 6r5q g4abhy7ja k7.uchexact locations of the genes on chromosomes are known. 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 de;jm7ux- im4et9l .ysd finition of linked genes?

  The diagram shows a karyogram of a brown male rat (Ratt30kuq(g oyo f,us norvegicus). Which arrow is pointg(o0q u,k3fy oing to a pair of autosomes?

  Mendel observed that there are two possible va2fcxa4vtwtg*(5: )km)g n bri riations of flower colour in pea plants, purple and white. After a genetic2a x:(kn45 twfim) * )vggtbrc 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 weqp*xw .; t.boll.89iqnu+drnight of children born in London in 1991. ndbx*p.;oqr+l.lt9quiw 8. n

  Which of these traits is an example of contin+ q61 sprhz.0k)g; ehp yenq;uuous variation?

  Which row correctly describes diploid and haploid cells i2rw3dbi 5m gaw6,a 5 e+4vmcmcn humans?

  The following table shows the diploid chromosome number of a range of speci uqz7m1uuub( d2x ry6vi+i,p1es.

Which of these statements is correct?

  Sickle cell anaemia is caused by a8)loc+:pav u v 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 tyz e nw.6wc;+q s*p9owfpe O. What are the possible genotypes9.q f+oenwz;6 cw *wps of the biological father?

  Which row shows the correct annotation of the alleles for blood oh*d ck8 q/a ak4bg2g*oe 2q om 5rwjz3cbr/-0groups?

  Which of these statements are true for al h1 rtqi3foe45leles?
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 malariagphw9a h7gc/ 55mm6rqmq mu) 0 across the contin70p6uwh9gcrm m )qm/a hq5gm5ent 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 przewalsvcl5 p2 dqrqfaf )7m0- mnte4-kii), 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 dominan5r-0dq mp a vlffm72t)q ne-4ct 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 genmtp 4ohd+qj pnxykg*8m52)m;k41arf es.

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

Sickle cell anaemia i*u h atb6nzm17s 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 homozygous for bros18q8hac5/ (+izfdelu;k (,w iviu, t:dbxzuwn, long hair and a female catwiu tduh,f;/kqxbs v+8: i(l8c(,i u5eaz 1dz that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), thebd/ qrfl qt- 71yaa*,(+chqha allele for diamond-shaped seeds (D) is dominant overd7 t+ rba,-qaq *flhqch1 y/a( oval-shaped seeds (d) and the allele for 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) isc(9y;bb vi6 47c*a o x4pztr+y/bhay m dominant to short hair (l), and curly hair (C) is dominant to straiga*/ymr(opxbb v 4 b 6azh iy;ct7y4+9cht 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 condition shown in. xqdf wt;fj;+x2u bt* the pedigree chart belqtb;t+w.dj u 2ff;x x*ow?

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

  Which of these statements about genetic rgsfvt5y)epgc:*g l(9fdy 0 ; 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 can show a normal 8iz9ikso.c3 pq ovm/.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 di.dq+a.g.90 b of,xjq2hny mt isorder shown in the pedigree chart is X-linked recessive anqj.mfiqd90ax,g bt+ h. o2n .yd not autosomal recessive?

  Different species of living organisms have different numbers of genes characterq,oi slnd,e5 3+kl86zwo o0pg 4(usvmistic to o6,dplgzwesv,o8u k inol sq035(m +4them. 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/ixijqqpel .yc.gk *l.t 13wj55t d k6 plants, including flower colour. If the pea plants Mendel was studying can onl 3i.ty* j1clj kx5g/q.6wektl5 dqpi.y 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 qgb1 lxzpe; of .qp(:-kq8+mj female without hemophilia have a daughter without hemophilia. What are the possible ge 8eol;q( :bz pf+-1.kg qjqpxmnotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annuuler+egl1 kv4:l4.w kks) to see if the genes for seed number and seed shape are linked. The critical va:4 lkrll w+gek1.k4ev lue 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 B can have a chil :n1auk7v9teh mrf.:,a9q3k e:mnbym d with blood type :mf 1etr qvaukn:e99kn my:m3b,a.h 7O.

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

3.Explain the role of inheritance in genetic diseases.