A man and a woman have a daughter and a son. Their daughter hqlrw/o6,f f*sas normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biologic,wos6/ fq*rlfal mother?

  Which diagram shows the sex chromosomes of a somatic ce,sd.yw.acz itr-nxe-ha3 d. 8ll in a human male?

  There are two alleles for flower colounco.t4p *g0tz r in snapdragons. However, 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 ob.o 40 gzc*ntptservation?

  Which keyword is matched to the correct def+ae(-*vx*er pv wr6g tinition?

  Which of these statements is a correct definition for mejn0 6 fla(qi*xwf*k36 k l)sa gene?

  The diagram shows a paivbhdy(jn d y+/.4e*ufr of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a rj9pjd v+p* w3+mrvg/specific trait, were crossed in an experiment. Which row shows tw* 3pj9vp rdr/+g+vm jhe expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a banded ax0nb 0 hjxy .008v.9uhiwdjlpattern. The non-agouti allele causes hairs to be a single colour. Individuals njwy hlhx0.00avudb .x j9i08who 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 individua /qbug q.z:x4 wmf3ea1q81nmsl pea plants was either round or wrinkled. The re.m4 qsqq8 m ufag1nw:z b3/x1esults 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 fl7 nz2uwo w+yy/y (Drosophila melanogaster) have 8 chromosomes. How many chromosomes are+uyzyw2/w7 on in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome pairs u/vu ,zb8+1e4o jmdx9p.u r8 f)x kftdoccur?

The majority of the genes in thevm1/k duc64 et;un8 he human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homeu4/;61 kmn8dhuectv ologous 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 yablc/p7:-m 9gj 3agfdefinition of linked genes?

  The diagram shows a karyogram of a5 vv8)3kvqbgj brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosg5 kqvv 3b)jv8omes?

  Mendel observed that there are two possible variations of flower colour in0 hl 7sva75p;of;eqrn pea plants, purple and white. After a genetic cross, the ratio of pl;nsf p he5r0;77al ovqants with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight ofdsv8:mtr-tv x;;ns 3a children born in London in 1991.3d;xs mvr ;:n 8at-stv

  Which of these traits is an example of continuous varu 1 ansgysh:4c wt4o.*iation?

  Which row correctly describes diploid and haploidllrs .*qf* uce8x7f+ d cells in humans?

  The following table shows the diploid chc7ob vn.80u8o vx 9vtq uwm8y:romosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive a mglni*1t :tx4llele (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. What are tv:y sck/:u1 4*ito epkhe possible genotypes of the biolog:ksy/ *k:14cou ipvteical father?

  Which row shows the correct annotation of t*8y415ac lfcx4u 2cb. h ruhlzhe alleles for blood groups?

  Which of these statements are true for allc(k v:n8leg 9uo7f6;qwp ,wepeles?
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 anu4ctnze;c28w dpvao/q.3fxeb x5r8vg 3q4 2faemia and the spread of malaria across the conti8xaf r8pgec2znfu;454tdv 3 q 2e3xw o.qc/ vbnent 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 przewalskxhm b/a0 * jnct*nc4t ec m-/*r8av*atii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tom b 0/t*vct-cr*amae/ cjtx8nan4*h *ne) 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 lin2,zz66 ym xjpvyd z22m(q0ai oked and unlinked genes.

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

Sickle cell anaemia is caused by the alepf;* cyh)q) ql; sq(glele 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 homozygi2c2iwiw w;vz8 t 1.0onwh.gvous for brown, long hair and a female cat that hav2t 210iv .gicz;niww.8wh ows black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-sl c*k7.ile0rd haped seeds (D) is dominant over oval-shaped seeds (d) and the alle dl kle7rci0*.le 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 (L) is domi y4iw* l-jw9qkx412z v7ry ywpnant to short hair (l), and curly hair (C) is dominant to straight hair (c). Ailpk2x9*wv y14j y zwwy7q4r- test cross was 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 p.yw-6j knrr6kedigree chart bj r6ynr.w6-k kelow?

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

  Which of these statements about gene3y8ww2 ahu u/ yjoz/*k ) kkcw.j8kb-qtic 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 c h3n:djz/h 1w 9l.jxzaan 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 inherito)(s m/6tp6wuzpa/j qnz5)cy f dm-9i ance of the disorder shown in the pedigree chart is X-linked recessive and noz95 oaf iutpm ny)w/mc6)(qjd6zp-/st autosomal recessive?

  Different species of living organisms have different numbers ctp vdo94xqmf; 56qiw h 3m*0jof genes characteristic to them. The table shows the estimated number of genes for five species. tm694v5;0 cwi*j3mx hopdfqq
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, incl11aaauakc/e: 5j )m2ag zd af3uding flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these s f aecg /a 3mzk:)1aju2aad51atatements was correct?

  A biological male with hemophilia and a biological female v:( /yrrx9m m xevbb,v:c7ir 6without hemophilia have a daughter without v,:xc 6 (rr/9bbxvvymm 7re: ihemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carrin4 bye- -)lunf3*qzi-fn*y hgz pc0p7ed out between 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 calg- nyi*3yz-z 4pl ph-n7*cbnueff) q0culated 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 childsze v)/6gg9ab with bl)e b69zg gv/saood type O.

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

3.Explain the role of inheritance in genetic diseases.