A man and a woman have ;t(2 ;dlqn o 1ij7wdqbsmqd: ,a daughter and a son. Their daughter has normal vision, but their son is colourblind. Which one of the;qw7d mb: odd;i(,t2s1nl qj qse genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of )uzsjf)sc mp*qtrr 0 ** ez4;ra somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the rsom6j 1k49 zvwesult of a cross between two heterozygous plants yielded offspring with thrmw4svj 6o9 k1zee different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to thei5h2i q 1j7 .uw(w zwve7.(zoxn2ad jq correct definition?

  Which of these statements is a correct definition for a py:aiqa ,* ) wprrfqe7t- ilt;*nb924/nrthigene?

  The diagram shows a pair of homologous ;lurf ,b63c vc rolhve;.nq*7chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, wer 5ir)tz7s2tjun4t,z se crossed in an experiment. Which row shows the expected phenotypic ratios 5 t4zz 2tit7rs sn),juof the offspring resulting from this cross?

  In some animals, the agos kj ::7f gzbh2/zgmt7zjbr:(uti allele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous hav2/7:7bm zs:(fg j j:bktzg zhre 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 plantj9l ,2.nidt r kbxn38os was either round or wrinkled. The results of an experimental cross yielded 315 offsprin9lo 2,d jkbxrnni38t.g 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 v8l:fmg.eyp(x;li 0t:bvri/ y g7r 4v chromosomes. How many c:yi:ev7gb fy rtxvm 4 08v r(lgi.l/p;hromosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome02mq6whg(*s*z nbni j pairs occur?

The majority of the genes in the human genome have already been mapped, mean -hlsan1fro*vs4*(w 4v lnv6f ing the exact locations of the genes on chromosomes-vow vfhs* sfv441la( n* rn6l 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 definition of linked gene.i,fib( 6 htgy3rw5f91citcas?

  The diagram shows a karyogra u:c9rw mnz97m9codc)m of a brown male rat (Rattus norvegicus). Which arrow is pointing onm9m 9 c)cr9d7wu:zcto a pair of autosomes?

  Mendel observed that there q :3*yvi ex y))qhhq,zare two possible 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 genotypihh)q:x) , 3vq yzeyq*es of the parents?

  The graph shows the frequency of birth wx1hqohy3)xp 8 d/kp cg:;m0wneight of children born in London in 1991. 1ydpmkw3oh:; x0pqgx n8/c)h

  Which of these traits iscu9pl7+lhgvy 6l 0l1 f an example of continuous variation?

  Which row correctly describes diploid and haploid c( b r3/pmx i9vm2+vogaz; ogs9ells in humans?

  The following table shows the diploid ch-q8zok/ g (n 3,a,c(e,rgjw/dnzi pbxromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by ;0c) aoj*o vt)m r)maea 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 bloodt3 au(8c-3d q tq*.f 5zqe -ixwngu+gn type O. What are the possible genotypes of the biological .qqgt n -n -t5u3c uze+qigx3a fwd*(8father?

  Which row shows the ci earba)p2 ge3uw7) w5orrect annotation of the alleles for blood groups?

  Which of these statements are true for a71dp +nak.v xtlleles?
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 and the spread of malaria acr/q(9x1yf udbjoss the cofx(u j 9/1bdqyntinent 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 (Egp oul8z+dd /fe fy(k,;kj5 j(quus przewalskii), 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 dominant to (ofk j(y;d j+glp/ ,fd8u5kze 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 unlpa 4j3+bb9qqeinked genes.

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

Sickle cell anaemia is caused by th**x:qm bo,yu ye 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 between3)l6v7 lrvvw z a male cat that is homozygous for brown, long hair and a female cat that has black, svllrz3v 6v)7 whort hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacu+vsgijo 2u03vu 9pi0rflz )h(nl ,x :jm officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short seu+:2hp,in3il9 gjv )fjlz xr v00uos(eds (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 5f* wwfmgi;g6.x ulmc s9gs.f .qp j53hair (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 guinea pigs jg56fsgf .. l.q;m*im fpxgw cw9 3su5and 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 inherith f 8cl i38uxloyf13 ci+br*;qance of the condition shown in the pedigree chart below? if1c; byh3r ucfix8o8lq+l3*

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

  Which of these statements about genetic disorders is/d iq7 f4y,3dcoare 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 tr,qpp 9w/si:ig ;eup,raits 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 inheritance of the disorder shown in th5bf;g5 s1fry l;lmm8 we pedigree chart is X-linked recessive a8rb;m ;fllswgm y55f1nd not autosomal recessive?

  Different species of living or10tzua; (k dneganisms have different numbers of genes characteristic to them. The table shows the estimated number of genes for fivza(tneduk01 ;e 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 pl g0(jk(xixee 1ants, including flower colour. If the pea plants Mendel was stud0e(jxk1 gex (iying can 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 biological female witho3il * mb g:glxv2 eg0vi*uwr9,- w3neuut hemophilia have a daughter without hemophilia. What are the pos-ir: 3e ,30 vwlnbgx we2mvugi*9lg*usible genotypes of the daughter?

  A dihybrid cross was carried out between twojg0) ei7pxypu 6z/p2t sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The txeipzyg276u0j/p )p 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 avyh2 odpgr1k50;6gke nd blood type B can have a child with blood tyok0512 grgeh;dp6v kype O.

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

3.Explain the role of inheritance in genetic diseases.