A man and a woman havep y+ww:l6+ ewy l*an;c a daughter and a son. Their daughter has normal vision, but their son is colourblwwn+p:*l+ly; wc 6ae yind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a humav3. mvey7p2a qn male?

  There are two alleles for flower c0v nt2;ccf mnr,xm3(kolour 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 likm k0x3mrnvc( tn;f,c2ely explanation for this observation?

  Which keyword is matched78x;la bg5z x p1agu7d to the correct definition?

  Which of these statements is a corh0y99n k+q ex k(ad/;dwc8 rabrect definition for a gene?

  The diagram shows a pair of homologous chromosomes.t 2ifaqedm1 q6h25tb .

How many loci are shown?

  Two individuals, heterozygous hcnh9o rkp1t . b/1bi da7s3(lfor a specific trait, were crossed in an experiment. Whid.(ha1obklct3 b9ps r h17in/ch row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes intg42a d+ww7jla8z k -ov3pa k,dividual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs wi4-7z 3 dk, l+v2gjtwaaaok wp8th 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 eithewhol3qszdf1 -t1 gv5 0r round or wrinkled. The results of an experimental cross yielded 315 offspring with round1-ld v0f q1gswzth35 o 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) have 8 chromosomes. Hf5 //xw,rgkw;.vtt foj+or1qow many chromosomes are in a fertilised oocyte /.5 ox/ rvw qor,gtjk1ft+wf;of a fruit fly?

  When does the random orientation of homologojx1pvp2n.c ayd53 roqt0v*6x-m jyz( us chromosome pairs occur?

The majority of the gene0q s:p 8ici(xfs in the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one repr0q:f x8iscpi( esentation 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 defir,gh +qmb1,cv nition of linked genes?

  The diagram shows a karyogram of a brown male rat (j/ xpkr: ojh03Rattus norvegicus). Which arrow is pointing3r p/o0jx hkj: to a pair of autosomes?

  Mendel observed that there are two possible variations of flower colour in b5e-3ddqz1jug wtemzk*, qc+m61 3q hpea pla,u53z-md z 1hq+gj w1kcm e3*q qte6bdnts, purple 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 freq8* ab(psyib6u i ,ck1cuency of birth weight of children born in London in 1991. u ibyc 8psi(k,b1c*a6

  Which of these traits is an example-l9uinle b 0byn4r8f1 of continuous variation?

  Which row correctly describes diploid and p ixom klk3*7 q2xwmfog0195 hhaploid cells in humans?

  The following table shows the diploid chromosome number of a r tzz90:vd 3eckzd*r.uange of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (-l 8ffz w/o2kvHb$^S$). 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. Whd s/*7,en haxea4 lakn4e:x1hat are the possible genotypee1h nkase :lna7aex4 h4*d,x /s of the biological father?

  Which row shows the corsao8e)m4dn;mq by t5aob* w6 :f *1daxrect annotation of the alleles for blood groups?

  Which of these statements are trua (6f6ic(dpb5 3st wmpe 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 malard(3mc+-: zefaf 0b tckia across the continent zc+ck0 (b3:tef md- faof 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 . psy63 rr*n:ubu1zhenumber of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (twrph y.b 16eur3: z*unso 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 betwee8h 1d31uvr uv/llj k4qn linked and unlinked genes.

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

Sickle cell anaemia is caused by the lc:m vsm7 3 ucmiy0mtq7s3i9+gyz- j /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 nir-msr im3ub iw4b 9*)m* z+ebrown, long hair andr r+m u*i mb4)m3wz- nbesi9i* a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinaniq8d zvu6:z4le), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dom:i6z8qndvu4z inant 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) is dom,h x*y9wk.vyjwb d ol1 r.z+4ainant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous long,k,4y .w1jx b+vlz9owhdra*y . 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 11u:jnk 5s 1d hnz:sohshown in the pedigree chart below? dhno js:zks1 : 5n1hu1

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

  Which of these statements about genetic disordk cq+ eq8lkc3* 8gf7zlm4:jue6z)9g jwiax i6ers 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 polygenijax sz1r2o)6e3noa ( hc 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 showop6v9 rxyu;t+,g p8 wgn in the pedigree chart is X-linkyvgrp;6,tu p8 x9+gowed recessive and not autosomal recessive?

  Different species of living organisms have different numbers of genes chara ;d)ckgm,mu5zr j6sdzs 78sw4);cfrecteristic to them. The table shows the estimated number of genes for w)zjz5sdg;6rc crme)k; 874,sdsf mufive 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, includingvo qqm4901jsl flower colour. If the pea plants Mendel was studying can only be white or purple and follov490mj sl1qqo w the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biologicqpn3 zo + *41fqnjdrvgcx8s)6al female without hemophilia have a daughter without hemop)qo +sf*dzgqc4 r3n16jx pnv8hilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants j gsix)t4e(4xa u)z6w5tc)q u(Helianthus annuus) to see if the genes for seed number and seed shape are linked. The cra (cjus4 xz4eit))5 tu6)gxqwitical value 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 anzy l,8r nvol5:d blood type B can have a child with blood type n 5rz,ov8y :llO.

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

3.Explain the role of inheritance in genetic diseases.