A man and a woman have a daughter and a son. (xsoqm)0ctpnzl/a yd1g 7/ r)Their daughter has normal vision, but their son is colourblind. Which one of these genot p lscnoxq 7//radg()0)1 ymtzypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a so gd0 :k0so ri:+5aiesymatic cell in a human male?

  There are two alleles for flower colour in snapdragons. Howevesoi f+4csbvymn3s,n89 ; d5wjr, the result of a cr, 3;fi dow4b+ 8nynssvjsmc9 5oss 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 tow()gx (ey - fl82gusza the correct definition?

  Which of these statements is a corrp okqt4)6irw 9ect definition for a gene?

  The diagram shows a pair of homologous chromos5sus7nrqvo3r7u tnm* )mpv6 3omes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an ;bh7pgx2 p(n aq9bh+v experiment. Which row shows the expected phenotypic ratios of the offspring resulting from this nhbvx9g2(pb;+7 qah pcross?

  In some animals, the agouti allele causes ij9rw2j 8l+e d.* bv:z4vvsty kndividual hairs to have a banded pattern. The non-agouly.*vks9djtv 4wvre8b+ :jz2 ti 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 eyfjfx(12t, f the seed shape in individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offsp(,ff yxtfe12j ring with wrinkled seeds.

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

  Neurons of the fruit fly (Drosophikr(ipdn7axyq5 :j ;jt sba9,jjw.39nla melanogaster) have 8 chromosomes. How many chromosomnsdw aj,b3akpiqtxn j : .9yr;95 j7j(es are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chrob+;jn k* /gv:u8sv hxqmosome pairs occur?

The majority of the genes in the human gen1 lq,,h krfqf2ome have already been mapped, meaning the exact locations of the genes on chromosomes q2rq,,hkff l1are 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 definitiz (br;c4 ed*y2jtfexg:muqy sl4 x21:on of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvd t;lo:z(0yu .0kixsvegicus). Which arrow is pointing (kdv :ulx.i y0to s;0zto a pair of autosomes?

  Mendel observed that there are twis0.p jdvba3g9 u:)cz o possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants wiujc.g3d)pzbis :09v ath purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight ody7 dwb0 e*fk7f children born in London in 1991. 07fdbk e w*7dy

  Which of these traits is an exampleui(* g eq8aleq6x7/vw o d18ep of continuous variation?

  Which row correctly describes diploid and dpw6f kx +onw v3(s43z-dddf :haploid cells in humans?

  The following table shows the diploid chromosome num .vs.h,4 wte,xkaqx/zber of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive aiji-b33s k, zellele (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 wrcd-w(jwslihz+n/ ea3-zf: 7 ith blood type A had a child with blood type O. What are the possible genotypes of the biological fn-/f7 zhwaw3zci dl:r(e s-j+ ather?

  Which row shows the correct annotation of the8 )gttc5r.* bzf wi7rs alleles for blood groups?

  Which of these statements are true vp7fz62kk ; p:gyuvmk1-ijy 2for 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 an621amg8vrw s taemia and the spread of malaria across the conti2mgav 61wrts8 nent 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 ny gsc-1jq 9g78 jg-kuyumber of gc8 7gyq jyg-1-sj9ugk enes. 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 unlinked17wn3uzwdk( ,t ns ydz/fqa xism)ne7t+;,k/ genes.

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

Sickle cell anaemia is caused byljnw:0f j(zg:6va g6y 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 c8vrlfus+)*fji0 acuq qr 40 *vross between a male cat that is homozygous for brown, long hair and a female cat that has blacku frc+s8r l4fv q*u0)0jv*aqi, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped sjlm3fm0rk * c .0ptjv oo1cm)h2 qeb2 :4sb-wbeeds (D) is dominant over oval-shaped seeds (d) and the allele for long seedm ro. cbep40k32v )0s*m2mtbj jq1c l:wf-ohbs (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),8mjazr ww8 k-+ long hair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross wz 8wwj+ k8-armas 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 the condition shown in the pedigrcckqvn3 3g6i. ee chart below?qg6 ci33vc.n k

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

  Which of these statements about genetic disordersq93mh d3aqcc6y q3 5u+z dob(p 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 shoiifp4ajpp4 ( .w 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 in u:n r,epp -9s0labi(xheritance of the disorder shown in the pedigree chart is X-linked recessive and not autou9sbe a p-r0 lni,:xp(somal recessive?

  Different species of living organisms have different numbers of genes character 9beiyu2,yvy 9istic to them. The table shows the estimated number b9yu y9, eyiv2of 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 e/oi3e:pw;oj jx84 tfof pea plants, including flower colour. If the pea plants Mendel was studying cant:wx o4jjif3e/o8 pe; only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biologicaz :sm j9pjlxe(j v-l(kv qa 5+t)wda/(l female without hemophilia have a daughter without hemophili- 9kaj(/we (zvvm x pljd)+ajq5lt:s(a. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annu7 0ae o8dceq(xus) 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 fooaq e8 x0d(7cer the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blp,ue -ykh jdq,x m::i8ood type A and blood type B can have a child with b,h,yux ieq:-8m:dp jklood type O.

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

3.Explain the role of inheritance in genetic diseases.