A man and a woman have a daughter and a son. Their daughter has normal vision ef*r(-5 9sunxj; ifm* pdizv,, but their son is colourblind. Which one of these genotyp, u5idpzmie 9n;* (js r-v*fxfes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somat7;e*fwvg q 7c 77mr4kkrp2k6lc; ep iric cell in a human male?

  There are two alleles for flower colour in snapdragons. Hoij2+t)k hu j.rwever, 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 observau 2+i kjrh)j.ttion?

  Which keyword is matched t n:c z**v3myr wr0p1ppo the correct definition?

  Which of these statemx 2 jo jnm+*ncvlvy;82ents is a correct definition for a gene?

  The diagram shows a pair of homologous chromosomes1z2 rpn.w lh*ca2 e,/ockwn ,re7ah w2.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, wen *(bsw ah7:bsre crossed in an experiment. Which row shows the expected phenot*swbb:n s ha7(ypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to .(5q) .v r6svmiybzvbyb l32hhave a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are hetm)y 6b.2zh(vi.v y5s qlbbv 3rerozygous 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 shaita,6oh +w:eezjd2/vj dd 2r0pe in individual pea plants was either round or wrinkled. The results of an experim2v t /o0 d2+ij,hzd deaerwj:6ental 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) have 8 chromosomes./0j)vv4 h7 hnhzexk xnwc32,q How many chroxe2hvnw v/c7zx 3q 0hknh4,j)mosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientaticnx3gx*gg1u ;bt j 40hh d x.xui:m;i;on of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped, meaning 0)y;p5qecraj the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a ;0p qr)5 eacjyhomologous 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 linamxso k;pq2 (evtv9 k+.w/j d0ked genes?

  The diagram shows a karyo/ 0c5lagnh8ajkb gu; ;gram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a a/0ga5k jn8gh c ;ul;bpair of autosomes?

  Mendel observed that there are two possible variations of flower colour in g f5bhhs(uc(r-9tpn vm0a00 vpea plants, purple and white. After a genetic cross, the ratio of plants with p90mn -vphc gtva5 hus0fbr( 0(urple 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 i/1mt g5vlidj viz035u( r pq)lwiu z::n London in 1991. lm5: ig0qj5wvv:1pu zl/)iui3 z(tdr

  Which of these traits is an exampmdi( u9.4 zayble of continuous variation?

  Which row correctly describes dipll 5j6csuy- 4ild x+wu)oid and haploid cells in humans?

  The following table shows the diploid chromosome number ovg1xi56 g p:j9kvw w+tf a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessivmijd+l +gl0mf8 ;xk3be 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 type O. Whar;2yuhjf o 6,xl lu76ot are the possible geu6uo62hoyr ;jl f xl,7notypes of the biological father?

  Which row shows the correct annotation of the alleles for bl2.ar)2l nu0c6,tzrnnq 7/jv fs0gpbkood groups?

  Which of these statehibkzsn dn8 c))/5vz y-3nci5ments 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 sickl4g 2 oylwookop8ki26- e cell anaemia and the spread of malaria across the continent of Aokkowo-il64p28 yg 2o frica.


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 d xns apvh1 6jgsm03osl:7ia e.n4r 9eu64m0ydetermined by a number of genes. Brown colour (B) is dominant to sandy colour (ajp: ss mx 6nmlehr49i0ya4 en d71 g6u3s.0ovb) 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 between linked6+ny0c ml; n* res7ppd and unlinked genes.

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

Sickle cell anaemia is cayuqn xwde, 9f1.-wppg 6h:8idused 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 browag07oniw; 5. iyaxp s,n, long hair and a femso 7xp na0;.yw,a5g iiale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinalunk.r 5h7y x9 bkx/;ryvqe 80ja7ij h8e), the allele for diamond-shaped seeds (D) is dominant over ovy8;h8bnkua7 9 5ji hrq.kex 0xryj7/val-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 mq+0stve t( fx 9qxt.-d2y4 dc(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-hairedv2e- 4stqd.cx+0t xtqyf(m d 9 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 zlfog0 iqs 2 c213((zot)k ls lz-nsf9inheritance of the condition shown in the pedigree chart belo2 sn9(otoiz0 2zsfcl)l1l-sg( zqf3 kw?

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

  Which of these statementsw9le3 o 6y.j;pou /zwj about genetic 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 distrie:6katx s/ufa1a2* b ,h)pw6r/nw pz lbution.

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 the p)./6ogx, .)cqgfea qo umhy0a fbeq96edigree chart isma fc)yq6qo gqe hbgou69 0x.f)e/a. , X-linked recessive and not autosomal recessive?

  Different species of living organisms have different numbers of genes characternv2 wb0cnul 0tf/7w m+f6v6v wistic to them. The table shows the estimated number obwn6+v20 c vfw6twmvlnfu07 /f 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,ws0 *1d/q 1getwc;alq including flower colour. If the pea plants Mendel was studying can onet w;d0 1w*clsqq1a /gly 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 hemophilia c/;(d1 :(- yyvufw+owlrhd)vu+r h;rasd l 1phav;a-phc;r( olfvd) ly1wu ruw: rhvy d+s+ (/d1e a daughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out beaq/i* adovm)d: e a;mx*p xw,,tween two sunflower 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 the 0.05 significance level was 7.82. The calculated value for the chi-squared test was 10.aida, m,aw/evp:xqd ) o* ;*xm05; what does this indicate?

1.Explain how parents with blo azew5 6n63wzvod type A and blood type B can have a child with blood type O. v nw 6z6ae53zw

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

3.Explain the role of inheritance in genetic diseases.