A man and a woman have a daughter and a son. Their daug )3cm;9m2l,aq yhi i-kw4kamr ng*hj. hter has normal vision, but their son is colourblind. Which one of these genotypes could be correct 2)3-*;cig h iymrj aqkw94,mk l m.nhafor the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell inkomv 80 0 7js9o2hmfvj a human male?

  There are two alleles for flower colour in snauta t awf6nk)j1i/nje)7x- ,gpdragons. 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 explanatio )eanjtf/x7ujk,)i ng1t6a -wn for this observation?

  Which keyword is matched to the correct defina3 dw pabmpbfl h(dcg:(r x212/1d il,ition?

  Which of these statements is a correct definition for j vbchtdet8.,2:1a l da gene?

  The diagram shows a pair of homo p) ; l5wrbromvl1 9ap;ogs9g;: qs8yologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous fh);/rp o kruw*or a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offsprin krwh; pu)r/*og resulting from this cross?

  In some animals, the agouti allele causes individual hairhb(g vpdd bxi5z/:s-n:/ 24bu ;csfcds to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have h bg(c/ :d25s4cnxf pz:h-i ;bdv/us bdairs 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 i cb. qinkls9z4tj+f k7,h)c5sndividual pea plants was either round or wrinkled. The results of an experimental cross bjs79+fz4nq . t c,5)klichks 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 fly (Drosoh /kb73x0vwh*iovv z7phila melanogaster) have 8 chromosomes. How many chromosomes are in a fertil*iz v7o/x 3b0vhv7w khised oocyte of a fruit fly?

  When does the random orienttb0f ,eq1gw)c xwr3) sation of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped, meann8931a. lwmi atoi z2uing the exact locations of the genes on chr.1im9tuo8inaa 23lw z omosomes 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 genesczba/8ku7 p7s ?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Which vkzzk9-y 6tuwo1 g*1sy7/yhcarrow is pointing to a paskc 1k6 o/w yztzyyhv91-g*u7ir of autosomes?

  Mendel observed that there are two possible variations of flower colour in9rg+,z *hi/r-npjvu f pea plants, purple and white. After a genetic cross, the ratio of plants with purple pjuv9* -z,f/nihg+rr flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight omq7 )3/wys zedxht151t fc: v5qw7xxpf children born in London in 1991. mdy ec3 fs7h :wtqz17xq5pvwx51 x)/t

  Which of these traits is an exampra7fpsc8 a ggkw9j( 1scf 1b05vv9-e ble of continuous variation?

  Which row correctly describenmlwstv,ux b q;4;pg+(k 9n5 rs diploid and haploid cells in humans?

  The following table shows the diploid chrom9ma7iclhnp/ 1gd4,ht osome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (H(eq-s4xw.2vp) h hr.blth:j;5e xvsv b$^S$). 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 Ound:;vn1ah j3l2y65ext0 gkv . What are the possible genotypes onnyd3u e;vx2 l0gaj6 5: kht1vf the biological father?

  Which row shows the correct annotation of the al+l4 o*bsbv ;.j8qs dblw m)o/dleles for blood groups?

  Which of these statements a mb12v;:)f5k fftk1h)ioit8g g0 wcswre true for 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 s y 6ew3t+rrc9mickle cell anaemia and the spread of malaria across tmr 3ey+t96 cwrhe 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 colour is determined by a num5,fyt0znu.8fc en. u yber of genes. Brown colour (B) is dominant to sandy colonue,u5.y .yz f80nctfur (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 betwee;r5f7 e tpb:lan linked and unlinked genes.

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

Sickle cell anaemia is caused by th k1knz df)-7u c,d3d nc7y3yspe 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 t;5u.eao s4 25pyghtmjhat is homozygous for brown, long hair and a female cat that has b sg5 45.utay;2omh pejlack, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for dia k50 idgu,hdp-mond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allelg,idu-h d5k0pe 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 porcellusmx*u rwkewu03 28nfxjxnzn -a7 (y (a,), long hair (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 and female short, straight-haire2*an8 y -xa un7w( w m(e,j0kxruznxf3d 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 conditi )rgy* ztqn8) grepd4+ fcac+94g zg7uon shown in the pedigree chart be 4rgqa*pf+ 7ct489d e))gz+ y zggrcnulow?

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

  Which of these statements about genetic disordeh u yn(-0-:yczc d3bikrs 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 sho m f*k7kw 5wf)rt 8)x2eicsa0dqeox4+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 inhb(h3tc9g6 j bleritance of the disorder shown in the pedigree chart is X-linked recessive and not autosomal recessighlcjb( 6 bt39ve?

  Different species of living organisms have different numbers of genes character,fy 1r6j.zp ypu0x 3rjistic to them. The r6j .ruxj01y3yz, ppftable 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 ofvltjsf a ptf by7l,l- +7h/.r6 pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follos7 rvta/7f.y,llfl+-bt j6p h w the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophilia h7q.drq al+q5w ave a daughter without hemophilia. What are q.7 lw+r qdaq5the possible genotypes of the daughter?

  A dihybrid cross was carr8 , v3j94pvqbmpo(u ycied out between two sunflower plants (Helianthus annuus) to see if the genes for seed nu j4v, bouypcq(vpm8 39mber 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 for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blznhiq;239crc( j hp(-6h n cdzood type A and blood type B can have a child with blood t (ch ;69-h qd(znhcj2rzc3npiype O.

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

3.Explain the role of inheritance in genetic diseases.