A man and a woman have a daughter and a son. Th7mdp6yq + +sbmeir daughter has normal vision, but their son is colourblind. Which one of these genoyq sm bd7p+m6+types could be correct for the biological mother?

  Which diagram shows the sex chromosomes of 8 vngkqhdq3ome 58/i( a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the result /6 e,z ezsmtmlz-y07iof a cross between two heterozygous plan/0z m-,lst6zi ez7my ets 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 correct d0:gh:m+u7vzcm-xlsj* , tp tz o o4pq)efinition?

  Which of these statements is a c8;ryz1 i/9q 8ucelkljjk/ y.zorrect definition for a gene?

  The diagram shows a pair of homologous chromosomes. lq 6:6 h .gy egc,-wqehn8do8w

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were cx3rvctv9o7aqdmo gd,4 3:.tirossed in an experiment. Which row shows the expected phenotypic ratios of the offspring t9 voiqot7da vx,g3 r4m:d .c3resulting from this cross?

  In some animals, the-2sw3o.tsxl .h 0ytdq agouti allele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs with a blq .wsd3s. 2o0-tx yhtanded 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 indup:)ds/jqn p; m . ux0.v3nosdividual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled se. vd.u3 oj:dx0psn;su)mn/p qeds.

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

  Neurons of the fruit fly (Drosophila melan,gc6gtspt xv) w8m.v1ogaster) have 8 chromosomes. How many chromosomes are in a fertili.xtv,g8) tv sc m1pgw6sed oocyte of a fruit fly?

  When does the random orientation of homologous chromjse5wdp7 o mt5.g7c 3baf lj/p .-k/peosome pairs occur?

The majority of the genes in the human genome have already been mapped, meanin zsw2rr1(;jsug the exact locations of the genes on chromosomes are known. The di r;(rz2w1js suagram 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 definip+*auv,t s lnw;y;p d8tion of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Whi o3:j/:b)ec ,bx9swqn* hyrxwch arrow is pointic sb)/x eyh:9b ,xnqw:r3w*j ong to a pair of autosomes?

  Mendel observed that there are two possible variations of flower ;mlki6qk,/xh 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 6/ mk,hxk ;ilqgenotypes of the parents?

  The graph shows the frequency of birth weight of children born in Londr3 ( :-ziweuppon in 1991 p i-3pe(u:wrz.

  Which of these traits is an examp u d*kuzr4xf(v*zk g94le of continuous variation?

  Which row correctly d4 ;l cubvr:2w2(hddap i.u el/ ;.aueaescribes diploid and haploid cells in humans?

  The following table shows the diploid chrgh djx19gx 4bm.3;sr jomosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused bu stbyp 5s,:yx1 tm339qoie9fy a 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 blood s7:6uy q:mpdx7nfr- ptype O. What are the possible genotypes of the p:nf:p-qdr smxu7 y76biological father?

  Which row shows the correct annotation of the alleles for blood l;:k wsg fg4p8groups?

  Which of these statements are truai( 5zj9j lh0radjtm1m-x:7 *wqp0x a e 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 sickle cell anaemia and the spread ofu p1(nd c,/cl;9*fw rd kz ei4kpmm4l. malaria across the c iplc/nrdf;p zm4u4 ( 9c.edml1wk*,k ontinent 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 b kjtb 0u.p be6aaq98btf -u0--n/ typqy a number of genes. Brown colour (B) is d ne/ -btkty 8.qp6jf baub-uap9q0t-0ominant 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 t)xbhvhj,l xr fm1*9:linked and unlinked genes.

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

Sickle cell anaemia is caused by the allelqyfpzszs4+qt 4ro: jf6;j;;ce 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 pi pr;g(i* :f l4s)xyphomozygous for brown, long hair and a female cat that ha*iy (;4rxf:pppil)g s s black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamondp9ycha 7 0bi8g-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant overa7i bgc9 0y8hp 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 dominant to short hair +fz)(xb3qh,l3 f p *;hmbxixk (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 femafq,)x3k+x i( hbz hl f;3mxb*ple 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 pedigree 4b n6v wc4n5zx4i t7,) jt4z c yyzs3utyvyf34chart c7fyy4w 4z4 y4ztcnyv ,nb3 ij3 vt4s6ux5t)z below?

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

  Which of these statemenow a.b q)89w)*pjbokk ubnxd:m0u.c/ ts about genetic 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 yvuah)2t- r uhjiy* 8cf.;pc-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 th i)uv84(csrtewc x)b3e pedigree chart is X-linked recessive and not autosomalu3s )4(tbxi )c wcv8re recessive?

  Different species of living organisms have different numbers of ybu6 2s/k rxkta4 ++n(*a-kljynt 3trgenes characteristic to them. The table shows the estimated number n+xt s -(/y4 rlk*2 bj 6r+tt3kankuyaof 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 characxvf5 rdvkn 7k0/ kx+*hteristics of pea plants, including 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 statements was correct7 5 x+nk* frdvkk0/xhv?

  A biological male with hemophilia and a biological f6 w+y;vz+g38hcyy8 a5qsc wmy emale without hemophilia have a daughter without hemophilia. What are thycm8+zvhy3 g;s ayw+ 86cyqw5 e possible genotypes of the daughter?

  A dihybrid cross was carried out betwpx9.k(01 rk xncchuu8 een two sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are luxupr kcc9xhn. 108( kinked. 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 blood type A q.t8iq-w zh )kand blood type B can have a child with blood type O. - wi8.qthzk q)

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

3.Explain the role of inheritance in genetic diseases.