A man and a woman have a daughter and a son. Their daughter has noxs74didpl(4f*+wa+ xw 6(r.t vlbh carmal vision, but their 6(*is.ar f+dbv l(x +x tlad7pwchw44son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes o.u eq;my f+fb7uy/ sm0f a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons.- 7x px+sxefwl-ysdv9*gh ;) y However, the result of a cro y)-+y hxpg sd*ef;x ls7-w9xvss between 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 h/,. w6mbx wgzthe correct definition?

  Which of these statements is a cogtiyxy+ 0nf;a /s e-z(rrect definition for a gene?

  The diagram shows a pair of /;yt a:gry1 sxhomologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific tra8do d/ivm.n/g z0p4j(a9n5 mg-xothyit, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting from this crosso0md zdm-gvaiyx(n/n t 45 pg9/hj8o.?

  In some animals, the agouti allele causes individual hairs to have a :c s cv-wdpr-*banded pattern. The non-agouti allele causes hai-cs-p:wrc v*drs 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 in indivi,dq y dw;7gpudfa+)r+dual pea plants was either round or wrinkled. The fdu;y q7agd +,dwp )+rresults 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 flyrd , k)2en4 .clcy7anv (Drosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilisedr.n7lda 4c nk2 cey),v oocyte of a fruit fly?

  When does the random orientation of homologous chrom:sn+wr;.tjw e osome pairs occur?

The majority of the genes in the human genome have already been mapped, meaning v :tug:)gkk bx8vy80- ;nzumythe exact locations of the gen8k :bt: v;yzkymgxuu8-g)vn0es 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 definitiofv+o((e4o)bx 8j br.hlznhg :n of linked genes?

  The diagram shows a h)kj r7a,9 ii/5us gjokaryogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of aut59o )g/,7jajk urisihosomes?

  Mendel observed that there are two possible variations of flower cbog: g t6lr.tpg19c+dolour in pea plants, purple and white. After a genetic cross, the cgtt. r+ l1ggp9ob6:d 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 Lonit ;kjoq hi5 9w3:u98y j.slhsdon in 1991. 9j :k93sjlouhsw. q 8hiyt; 5i

  Which of these traits is an ex6:n7f.mc.eb tzn* ixd ample of continuous variation?

  Which row correctly describes diploid and haploid cyfvxfps srz2*7/ ycw )(gb:l-ells in humans?

  The following table shows the diploid chromosome number of 5fi rr)5 6kw :ugpd0rwa range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessiv;lha3 hsn1hnlovow dag02)o 0 k5 d(1se 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 6 7zp7gw3ekmja h5(lgwith blood type A had a child with blood type O. What are the possible genoty mz3w6ajgg 7e5 lkhp7(pes of the biological father?

  Which row shows the correct annotation n4ff4q t8t/ce;q2g es of the alleles for blood groups?

  Which of these statements are true for allelesewp.fodu:y6 +jfqv ai9v f 2h 9im52h7?
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 h1rq s56 7ad5n pr8ypgof sickle cell anaemia and the spread of malaria acrhdp7n1yga8q rsp5r5 6 oss the 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 coa gmz7brr9ymeklmmol 3m+ 98 --3ev(plour is determined by a number of genep7k 3+ 9zyl-8 em-a9vmmrobrm3 lm(ges. Brown colour (B) is 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 between linked and p:o3krxgxz - )unlinked genes.

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

Sickle cell anaemia is caused b 5vi vpx0(,u;tis pbg8y 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)zc:c x*ty wkb1v 2ra)scn9b. for brown, long hair and a female cat that has black, short hairz:12c. acxkbwny tv)rc)*b s 9.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officingpjln3/c(e/ t xu7*cdale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominanu3jce7ct*n/ld( pg/ xt 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 ,0sv o tkwr)(h9s*kvk2+gfmg cyj; .fshort hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heteroz9cf ky2g;ksfvw 0) sjogtk(*mv+.,h r ygous 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 27 e);q :3stu hbr.yv ls:q9tpwewk5mof the condition shown in the pedigree chart below hs.qp2ksteu3l5q 7vwr):ty9w;b e m :?

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

  Which of these statements about genetic disorders is/are correct? b3 dpc **pmfhh.m 8gog6pvhv+ b2 b:n8

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 trait1 8g5jjnpc xq0.k(q85ujzfi us 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 th(wgh-f( 1sno ie inheritance of the disorder shown in the pedigree chart is X-linked recessive and not aun-( gows1hif (tosomal recessive?

  Different species of living organisms have different num4o3 q.1m,lpbi ajf3s ebers of genes characteristic to them. The table shows the estimat 3fbos.,4 pmil1ejq3a ed 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 chaxc(vkt:,)xgyc f+ mu21x 4jglracteristics of pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, w2tm4 kcgx:j()c1, gxfx+vluy hich of these statements was correct?

  A biological male with hemophilia and a biological female without yj4a: os vonkny7r6z f9:aq::hemophilia have a daughter without hemophilia. What are the possible genotyaa fnk4y v9::ro7qn s:jzo6y:pes of the daughter?

  A dihybrid cross was carried out between two sufxx6:vn22- b9 w0xfeuemi1yh nflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical value for the chi-sqnvx y bf2-2 1ie0mxhuw:fe9x6uared 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 child b/k/+fzo y *wr83yvjyg7pav4with blood type O. b+zr 3k4wjo gf/p ay 8/v7*yvy

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

3.Explain the role of inheritance in genetic diseases.