A man and a woman have a daughter an(d5*y;er b0qeopj, d dd a son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for thee5bdp(qde r, jd;*oy0 biological mother?

  Which diagram shows the sex chromosom;cq8jci 0f- z1jj8tsses of a somatic cell in a human male?

  There are two allelesquk2 7u2i( vptgq,0vs 6 hi0niph7u6h for flower colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flow07quq0sk2nhvtu7( hi26vhigp u6p i,ers. Which is the most likely explanation for this observation?

  Which keyword is matched tn yjlp7-hd.*be rvr. *o the correct definition?

  Which of these statements is a correct d,h6 os- yvlyozb3: wj/efinition for a gene?

  The diagram shows a pair of homolu;ygir4z+kk98o7ovu8 v)**(o awxry i sjsz7ogous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in.ec 49u c;1ays egjczrg 3zkryj,1 f)* an experiment. Which row shows the ex c3;yr*zr esck91 ,1jygg.j4 u)fze capected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to havu.7 jjjg2 cr5+e4tey4t0l wspe a banded pattern. The non-agouti allele causes hairs to be p j+u5e0 .trltw jy7c2g4ejs4 a single 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 inz ew+cgkmqj 86v5u-/j individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds +kjqz 6u58-wj/ecgvm 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 mela2;t4c ;lfw apnkxjq 6+nogaster) have 8 chromosomes. How many chromosomes arejt xpaql+ n6fc wk4;2; in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chro kt6d+ pri svo7)hq**xmosome pairs occur?

The majority of the genes in the h6 z)0cy4,fs -lgw ifjkuman genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one repffsyl6,ig4-zc wj k) 0resentation 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 gkp 6bau)7)zviz1r n -sfm, z/6uovd5menes?

  The diagram shows a karyogram of a brown male ra2okd r :w*m;vut (Rattus norvegicus). Which arrow is pointingovkmd2u*w ;: r to a pair of autosomes?

  Mendel observed that there are two possible variations of flowerj ; ou9pz)ggq- 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 )9- gug z;pjoqthe genotypes of the parents?

  The graph shows the frequency ozon e 8g*sn3ye+0:qqz;z k, syws79 trf birth weight of children born in London in 1991 keeqn9r ;s ysg3wqzs70,t z+ny:* 8oz.

  Which of these traits is an example of continuous variation?lqqb 1gpuh)1 2

  Which row correctly describes diploid and hafvr28rfk yq )jr f055 0c:gfdaploid cells in humans?

  The following table shows th /n4uiso4las n6d qfmtl1 )4,ze diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive a/ps b 3.lh5susllele (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 1ejud):cgn9r 3 ; xpplchild with blood type O. What are thxrp1)cl3 p9gund j:;ee possible genotypes of the biological father?

  Which row shows the corrwzo4 6izifaj3)tpk,10p x7 zoect annotation of the alleles for blood groups?

  Which of these statements are true for allr;c *bjy9;hohk+*8ksqhw 9 oreles?
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 an)i: l n sem*6aj:2nniad the spread of malaria across the continent of l:2sen i6ijnn *aa ):mAfrica.


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 prar xga fn+x )hm(0-/vqzewalskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) (0 x)r xh/ +gvfamqna-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 u wzv4(tu k ieoj3:l:a,nlinked genes.

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

Sickle cell anaemia is caused bw7n,5 2ciqa rzy 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 is homozygou+ y/*gbxouau7 s for brown, long hair and a female cat that has 7 xb uy/*+oagublack, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shapgwz cnc.(jn5 tqk-s63ed seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) 5(zqscj6t3gn. nkw- cis 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 dominant to s n3l: -pm l;98qduawflhort 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-haired guinea pigs and a chi-squared test (χ2) was ca: 8 -ld9wn3p;ulfm laqrried 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 thx+vb ;h/is8n-.wp jr6jx2d zae condition shown in the pedigree chart ben rh b zs/.8+j;wp2 -jvxax6dilow?

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

  Which of these statementq/ evfk9 u8lhok. w(2us 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 can show a normal distm72t qf;fu a:f2vo f.wribution.

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 pedigree chart 36ogi-,njy-gf- f ov,vb 7apnis X-linked recessive and not autosomgo of -7gn6vin-, bp3vf,j-ayal recessive?

  Different species of living organisms have differenn1c w:, ll*bh xr,vd:ut numbers of genes characteristic to them. The table shows the estimated number of genes for * u 1ld b,r:c:nlvxwh,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 fg(db ,fo j9v5kqn *5b50udijhlower colour. If the pea plants ojd0*bnq u(5h5fdg ,9v5kjibMendel 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 hem*g a8 w5me3 q2fks)9xq-okmvx ophilia and a biological female without hemophilia have a daughter without hemophilia. What are the possiblg-x xaoqwvfe8kq3 5mms 92*) ke genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Heli x(l-bcng3m 2nanthus annuus) to see if the genes for seed number and seed shape are ll3mc-2nn (x bginked. 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 and blood typnj-3qn: 3r*eko kd ev(e B can have a child with blood type O. dker3 nq -k3ov*nje:(

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

3.Explain the role of inheritance in genetic diseases.