A man and a woman have a daughter and a son. Their daughter has normal visdg 5t/uk81 ;ofi o0d8omuku *fion, butkk o ud midgf5; t/81uo*f0o8u their son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a 1uf9els9q5e 0phe ;,t q lvhm*somatic cell in a human male?

  There are two alleles for flower colob x zp ;u.wnr ,yn+om; 0cuk*qot,)j0our in snapdragons. However, the result of a cross between two hezy b;x.)kuq,pr0 uo*, n0tj+cnw oom;terozygous 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 c64aows5-hnrn/ 2 b3a rn)wingorrect definition?

  Which of these statements ifv:z3sc xla606 wvl;qs a correct definition for a gene?

  The diagram shows a pai*px p z6zs3/cb, ngt3dr of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific travf haqrp,kw. ;./2mgp it, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting from/wap m,r;. pfh.k2v gq this cross?

  In some animals, the agouti allele causes individual +s -f. km9se egi5lg2chairs to have a banded pattern. The non-agouti allele causes hairs to be a singlesl k -m5fis2ee9 g.c+g 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 individual pea plants ws ,z w8xpg 9uf)5dklt0 v8b.bcas either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds anfcg9x ,pt wb5 z.d)v8b8sk0uld 105 offspring with wrinkled seeds.

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

  Neurons of the fruit fly (Drosophilw+ a:+xkxgo7nc4nfn:uxo:8 4ee n am(a melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oo aon:x (x +men 4eng8oxn:ka:u7w4 fc+cyte of a fruit fly?

  When does the random orientatio6rn)4 zrc d56 r*s yqdp,qs4a-eem s+tn of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped, tky (.)bwqkk. meaning the exact locations of the genes on chromosomes are known. The diagram b tyb ()kkw.kq.elow 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 definitioadtb 7;r +os;8ri qfyv w-t etq)j:o3-n of linked genes?

  The diagram shows a karyogram of a brown male rat (R;6 jfx g;bb2czattus norvegicus). Which arrowxc6; z2bbf;j g is pointing to a pair of autosomes?

  Mendel observed that there lh1 kds;kq18g+0vxp nare two possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants kg 8nhxdsk+1 1v;p0qlwith 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 ind,20fgsrcgn u9b k1i fq)5x.z/ 9gp cg 1991. q)g2bfx5z/cgi pgs r9kf,9 ndu10gc.

  Which of these traits is an example of continuous vls8dggs, ln f *r25ny/ariation?

  Which row correctly describes diploid and haploid cells injs5 yv(47,:m+ c tnrqodarjf 7 humans?

  The following table shows the diploid chromosome number of a:ehmiqn eh2g5 tj;g in+v6w0 8 range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessivmkvr(gj4 w: *ee 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 wx8 +x9s+3d8a.v c7nl rycukq6,n w+e9uzzsbb ith blood type A had a child with blood type O. What are the possible genotypw cu+8 +d vx9lkqy. z9,6b7xcrb3szan +nue8ses of the biological father?

  Which row shows the correct annotation s.ddl 1(og/saof the alleles for blood groups?

  Which of these statements are true for alleles0 a3e)r9ib,g 9er usnugd fq:*?
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 inciden g8oefmpx96li20 9f udce of sickle cell anaemia and the spread of malaria across the continent of Africdi28g 0fumpxe 9ol6 9fa.


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 xix3;ix0asxd)* shaqe 4 h5r5przewalskii), fur colour is determined by a number of geixi4 * 5s03ehr;5d axx x)qahsnes. 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 unlinkompk85r)xv+h5pqgz b /q 4 4boed genes.

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

Sickle cell anaemia is c+d olkjxtg 4t6 gngjh :25*k30-b etegaused 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 lcmx5-3nfa: 1v, f kl lt-paf6is homozygous for brown, long hair and a female cat that has black, -tpm3 f a a5:x,l1nk-6lfvcflshort hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum: d0wc(f x01tcwhw1nm 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 seeds (l) (cx wdfw1 w0t1c:nm0h.

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 short(3lan4 -yn17dfko s(i mc8oft 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 and female short, straight-47cnmo oyn f(k3(il1s dfat8 -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*t+k bos)gjw - shown in the pedigree chart below?+o tgwk -*)jbs

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

  Which of these statements about genetic disorders is/t 8qw (ai h/3isf0flsxw520dsare 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 w6qxr7a84 xp dcan 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 the ez6*yhlv(c+gfnl qak.( 3 l;lx( cvm0pedigree chart is X-li hyl(a 60l.v(mlfxlq*(gkzv+ ;e3 cncnked recessive and not autosomal recessive?

  Different species of living organisms have different znwes1-c:b8g 8pd(+ouyw gp,numbers of genes characteristieyp 81gdzo+n:w 8pb s(cwu g-,c to them. The table shows the estimated 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 characteristics of pea plants, including flower colox3,ba2-je*q dju 2o n71 knzzmur. If the peabaozxq3mjn kdu 2e j-71nz,*2 plants Mendel was studying 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 without hemophilia han6x *pc; lb bdda:7(g rq+wd4eve a dagld6(xe+47 cp;:*ndqbwdb raughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out betwurc p pmzm4c( -besr950,a p,2an f,rzeen 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 si2c bpc(rr5zra psa ,fe,4m,-n9zp0umgnificance 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 aanis o o,ro) 9rg2tm;3rr 54ovnd blood type B can have a child with bl2,oom;n4voar rr5g9 rto 3) siood type O.

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

3.Explain the role of inheritance in genetic diseases.