A man and a woman have a daughter and a son. Their dak; 05er fb7:+g+ektowx.laekughter has normal vision, but their son is colourblind. Which one of these ge+lfe wgok rab ;k+ e.57txe:0knotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell inp:k1p hog4aj 8 a human male?

  There are two alleles for flower colour in snapdragons. Howev-la 0m xem,* 5rd5nruwer, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowe0 alwu5 dr5mn r,m*ex-rs. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct dec9fb st(k7ck*0m5ps jfinition?

  Which of these statements *db xtzfxnu)y, olf2f )/g(bk s6gk4 0is a correct definition for a gene?

  The diagram shows a pair of homologous chromosomes. y/)q66zgg b1c ocg0hv

How many loci are shown?

  Two individuals, heterozygous f nso4cmzctg9s k8970 qor a specific trait, were crossed in an experiment. Which row shows the expectsc tsm7gn0z4899c q koed phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to ha t:7cq-q7 cvb qp:7/vp,zkf wkve a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous /t7 b zcwv7cvkqpk-qp q,7::fhave 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 plans 7 96a xqjoz *5appmuqt+4ri5o h4x1rts was either round or wrinkled. The results*46+oqxxj o51 7a95thpirqpus a r 4zm of an experimental cross 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 melanogaster) k- 6s, mey-dvohave 8 chromosomes. How many chromosomes are in a fertilised syk, d-v-eom6oocyte of a fruit fly?

  When does the random orientation of homo,5 fr wz +nyyo :/xcd+uka,npk43js7 s8obru 9logous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped, qk2;eqy5:1.m xqbd :g y7)rxyqxj s)t meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of )xkj.q x) y1tg: qrym2s x5q:ydbq e;7a 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 definition of linkz ktd6l-nyv8-35/hs n cjte g;ed genes?

  The diagram shows a kar7z sb):mpl,t zf qk0a3yogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosomes)z b,ast7fpm3 :kz l0q?

  Mendel observed that there are two pooi e:4a:(s ivwssible 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 were the genotyps v:4aw:i eio(es of the parents?

  The graph shows the frequency of birth wei*1g+e qc8js y,e1sctu ght of children born in London in 1991ytq s+8ce1sec jg ,u*1.

  Which of these traits is an example of continu+5(qw x 8n:7aevg txgious variation?

  Which row correctly describes diploid and haploid 6q56 fvpl 7 5e;pwmnkx3, t ylp13jtzpcells in humans?

  The following table shows throzo/ .*ov z4pe diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caus mdxw l59 iuf-xr+yr.-ed 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 hap7ww-83i ap4duhlecr1c4e6 r d a child with blood type O. What are the possible genotypes of the biological 7w4-cecap rrlip6de4h 8 1 wu3father?

  Which row shows the correct annotation of the alleles for7eec;0/ss i rb blood groups?

  Which of these statements are h*a1rwe0cnx1 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 sicjl* )6f njw1bfv.(k fykle cell anaemia and the spread of malaria across thjkj f)n.*v6w(l y1fb fe continent 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 przewalo wmi9 ,v/w,glskii), 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 domino ,iw9lw ,/mvgant 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 and4m3vb v fes/3h0j u:nl unlinked genes.

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

Sickle cell anaemia is caused by the+sjsk1hv4 x cc6 v .m;bxry9;s 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 shot6zk;-.brp xv8d5k rmws a cross between a male cat that is homozygous for brown, lmdt.z6 ;- rbkxvp85rk ong hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele pa 7ymm.(o o173awcvffor diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is domw1om vac (73mpoa .y7finant 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 dominant to short haii ;j:w 4jx0ukac yx1t7r (l), and curly hair (C) is dominkj 7xt0yw:x;1cjia 4u ant 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 thecy 7 rxglh5 8rch/4onb;xv v;* condition shown in the pedigree chart beln5 grcb7rvx;x8 c/hhyovl ; 4*ow?

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

  Which of these statements about genetic disorders isc(p8m (-xgn 1vg7uxqp*tzl9+b0 yvsd /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 )7ru+ikii/-(ipz )aq0 kp2hzh j bl.itraits 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 mhnx 9idfy s uql*08ve 8qp8*nad 17v2inheritance of the disorder shown in the pedigree chart is X-linked recessive and not autosomal ra np72eif8 9u *n *8hqvq8sxdyd0l1 vmecessive?

  Different species of living organisms have different 2qq 5pxb)ivh jdqw2: 0numbers of genes characteristic tq2x)v: h 2djqiq 0pw5bo 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 characteristn7 4 n;vmesn oto5.zk6ics of pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of M6o.k7s m n4nnto5vez;endelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female withoumtlk -+zi:c- ht hemophilia have a daughter without hemophilia. What are the mti-hk l +:c-zpossible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants ( 5fm2iu 9k3wlyHelianthus annuus) to see if the genes fmf9yul5k i2w 3or seed number and seed shape are linked. The critical 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 and blood type B can have a chilia(q w-u0q 3y8 h d1mk)oxzlf,d with blood typkq (wyq8 ,-z30 uham1x ifldo)e O.

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

3.Explain the role of inheritance in genetic diseases.