A man and a woman have a daughter and a son. Their daughter has normal vision, t2edp4 )f x ckx.n9q-dbut their son is colourblind. Which one of these genotypes could be correct for fq-.x9 kx e )4tndc2pdthe biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human ma/ ob2 xx2w;cq.*) gjfnkv xd1ple?

  There are two allelesbsp2gf xtl0bp 1 ca*), for flower colour in snapdragons. However, the result of a cross bet2l ,b* f1pp )cgts0abxween two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correc8a/.bohvu z5 dt definition?

  Which of these statementsnswel o0wrl8af,l s06(/ eqdj 1hc;: w is a correct definition for a gene?

  The diagram shows a pair of homologous m .6p y(lkks8bchromosomes.

How many loci are shown?

  Two individuals, hetb *mg3o1: -apmfedycrl+86z y4c(qh eerozygous for a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the o aoc61 yf3 m + 4crqdyze*hlb8pme-:(gffspring resulting from this cross?

  In some animals, the agouti allele causes individuax jci 1waw+8lzk bcg;1, 6/o,l mxhw(il hairs to have a banded pattern.ja+b i8o611zg mkclx cxi,,l;/h(w ww The non-agouti 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 1sa q2xs k2t7 s2a:7snlbo6ewin individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinsb 7oe a6t 27:ss xs2alkqn12wkled seeds.

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

  Neurons of the fruit u1 iyl7.0w: xt apw0zkxy hnc;e d/6a(fly (Drosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oouc: tplhny7wx6k/e .a(0xwad1izy0; cyte of a fruit fly?

  When does the random orientation of homologous clq:w +sru1 xemoa:5+bhromosome pairs occur?

The majority of the genes in the human genome have alv d*z1 (2*m tgrxyr9mnz8fg; iready been mapped, meaning the exact locations of the gen tgmmz ryzr9df821x* *ngiv;( es 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 defini)9u v0t( h m*imapk6hftion of linked genes?

  The diagram shows a karyogram of a brown male rat (Ra4h9m s.lpbc4x0 lrq8attus norvegicus). Which arr 4l8 b04qc9mlrap.x hsow is pointing to a pair of autosomes?

  Mendel observed that t5lxasx6; t 4nghere are two possible variations of flower colour in pea plants, purple and white. After a get4 6ax;sxn 5lgnetic 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 weight of children born in London iadq)qn /w;xdk: *sv1f64xttzn 1991tq*4tsn/ kd:dwa 6 ;z)qxfvx1.

  Which of these traits is an exa,btz-eqjeyj f-c t90t g)b 3e*mple of continuous variation?

  Which row correctly 0 y,v7og: r l8g-*akulnt; hl:w/mblydescribes diploid and haploid cells in humans?

  The following table shows thkw*a, ll3* y/6 ik,d,lt l4qeo6luapve diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia i.vzi4n6020iglu on( cy b km)os caused 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 had a child with bloorwn f7:i9s3q 2 aba,fzd type O. What are the possible genotypes of the biologica 3s: qrb279, anafwzfil father?

  Which row shows the correct annotation of the alleles for blood groupsdx57*) srpzlc ?

  Which of these statements are truex:1vglr. :i5i )lutjup / nfdr15ymj+ 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 andf+.p zmd xi5 skhd6vc1 lldz4:,i3zv * the spread of malaria across tz,d64fpm3*iil51x z.kh vzs+:v d cdlhe 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 przewalskii), fur colour is determined by a number of 2slqv 4;jf )dbd.9hvp genes. Brown colour (B) i.;d4sv )d bp2q9v lhfjs dominant to sandy colour (b) and an ombre (two 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 betweenav mgl(qtq)) opxm :9in5v3 k- linked and unlinked genes.

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

Sickle cell anaemia is caused b)oy s.qx/g8f6otd/y oy 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 homoz1:5lu xqh d6d +vpdysdkqo-*g i2+: uhygous for brown, long hair and a female cat that has black, shxh: qq1 -2* dl5vhy+k osdpu6gu:d+diort hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele5 2il7 xos cebf/7p3df: hs*dp for diamond-shaped seeds (D) is dominant over oval-shaped seedph islxff od/523p7 c 7ds:e*bs (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), loti-g3 zbz+i f7ng hair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous long, curly-haired guizii3-gb +tz 7fnea 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 e,awa *p,u; gm bq1+n vb-tcs+of the condition shown in the pedigree chart below? v;+bpu- acn,b m1+twa,*e qsg

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

  Which of these statements about genetic disorders is/kc aa)t(tg ;gbr.o +b+khcp)7are 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 distrlamf6*e 6jf.d74n 4l-nq 8ltw rry/ujibution.

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 shown in r :xr/o/z a dhsbj3 dt*+i*c53jm1nh wthe pedigree chart is X-linked recessive and+n5r d h *b /cd331 :*mhji/wsaxotrzj not autosomal recessive?

  Different species of living organisms have different nu poj . sn ll+8vsvr 7mp6vw-bpc.2w/+umbers of genes characteristic to them. The table shows the estimate/pv+nbso vlcpwu- +r.7lvpm28 6w. sj d 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 characteristi;v/,z;3+q 5. tubpggfqc pttm cs of pea plants, including flower colour. If the pea plants Mendel was studying can only be white; 3;zqt+tbpmtvc p5 ,fgg/u.q or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological m2y7hs; : s v8j:cimacurh1 m2female without hemophilia have a dm ;cu27j8iy2s amrchs v1h:m: aughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two s//dr:ly*sjeyle 3wk w 1ej3r.unflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical value for the yywr/w*dr:/ e klsl 1j3j 3ee.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 )pkc i3xk*gq8wxxsj-5pg 1/vnxv;sj7i : v 6mhave a child with blood type *xvk-/xj)6qsk jsiwgmv;x:57 n8 cp3i1vgxp O.

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

3.Explain the role of inheritance in genetic diseases.