A man and a woman have a daughter and a son. Their daughter has norm/8yi;o; hmpr xal vision, but their son is colourblind. Which one of these genotypes could be correct ;/xipy; rmo8hfor the biological mother?

  Which diagram shows the sex chromosomes oyrt ,fch2;r o9 nfq4g;f a somatic cell in a human male?

  There are two alleles for flower m 2 014gfftcrvt5 +pbgditx,6colour in snapdragons. However, the result of a cross between two heterozyt5im t tfrd2gxv+ cp0 ,g6fb14gous 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,zp ut5-uq+ qm to the correct definition?

  Which of these statements is a correct def7 0ze/bahs .sqinition for a gene?

  The diagram shows a paij di* d.mkt 2pm+*sih8bf) te9r of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an exper9yi()r kz1- yobhjs:riment. Which row shows the expected phenotypic ratios of the offspring resulting from zyi(yhj)- :br 1 sr9okthis cross?

  In some animals, the agouti allele causes individual hairs m +jlu+9u2gqb to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individualsljqug2 m9 u++b 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 3-nl974 l,wl)rbwysb xa.zr fin individual pea plants was either round or wrinkled. Thewf lb7lx,9z w-43r) yla.brns results 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 fly (2kgu+ jj pqd+*m8z9bwDrosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fruit fjp*2jg8qw+9zud+b km ly?

  When does the random orientation of homologoy5 3l gzcahfvtq.h7vbz +jf7 *b)u 3p0us chromosome pairs occur?

The majority of the gened*h5mwa/r- dgs in the human genome have already been mapped, meaning the exact locations of the genes h/w -5mdga d*ron chromosomes 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 linked1 u.m8mcdcw9;*o+z e yq,ztwx genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Which arv/ddbmo,,e 3++c oxpwrow is pointing to a pairx+,/ p3m bce,ddovo+w of autosomes?

  Mendel observed that there are two possible variations of av e32vds48emtyhf:. flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to 2s:.h df3e4mvt 8eayv white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of pro3.hsbps/;y zhb+ )e5 gdl: l.zjt3birth weight of children born in London in 1991.do :lzeh)5+ s3gpzb; /r h.stlbjp.3y

  Which of these traits is an example of continuw 4ow;k)v5r)zkmq 8d uous variation?

  Which row correctly describes diploid and haploid cells i9ga dwx2e *sz3,towy0 ;at/t(xsmh9y n humans?

  The following table shows the diploid chromosome number of a ranwf jg-,2elrc--cp) ff ge of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive aferqy88py a yn- 7r/y*llele (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 bllzet8* p5 cemfeuh)16;c z)oy ood type A had a child with blood type O. What are the possible genotypes of th l*o mcfh)c6uez;p8yz1)te5e e biological father?

  Which row shows the c q8fr t1nf, loq.;n:mwu,eg-eig:id+ orrect annotation of the alleles for blood groups?

  Which of these statements are true for alleles+ysorzf97))rsv:hom -rsi7g ?
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 s4vww3dehbx 3r 9mzg 7:pread of malaria across the continent3hzw:wg3 e4bd7 9xrmv 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 ey4y elf :2rr7f2v4t/p e+ kxsnumber of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is domin4s+lp4tvry e y:rfe22kx fe/7ant 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 linke a6en,qv d9i3abr lh7eb64o4od and unlinked genes.

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

Sickle cell anaemia is caused byl 4jq/my8 (nfz 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 homozygo.k 3 san-cz*r20fv df:hbcm b-us for brown, long hair and a femal3hfc -m.0bkv-dr*z2 bacfsn:e cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped s1-izr(ch t .omeu i7x-eeds (D) is dominant over oval-shaped seeds (d) and the allele h7-eixu(i t1-.mo z rcfor 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)(7 cza7umumq z3j ndynu.;3t:, 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-haired guinea pigs and a chi-squared test j(:u.3 muyznd uncz 3a7 qtm7;(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 pedigr22gldjf)3 o cgee chart below? g2)cfdgl2o 3j

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

  Which of these statements about genetic disorders is/areg/* : ) 0:nhrdebyblce 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 polygenf:*u*u lhm,fao+ wtd70*hxlw(zwu qu3 ,om m8ic traits 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 /er5yosse(kl g/f7r4the disorder shown in the pedigree chart is X-linked recessive and not auto yeefgk5s rl4s(ro/7/somal recessive?

  Different species of living organisms have different numbers of genx( t 0w rxbg-1vggy1t9es characteristic to them. The table vtt-1901x(gy bwggxr 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, ind rcqwm9b g03/g7mim/0gj8x g cluding flower colour. If the pea crgdm//jbmi03m qg79g0w 8g x 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 u l1 94+xpjrcoa,)znrfemale without hemophilia have a daughter rxjo4p l c,zau)9n r1+without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthusbmq xwjbbp4,4wq/ 9d 6 annuus) to see if the genes for seed number and seed shape are linked. The critical value for the chi-squared test at the 0.0b4w,q6 bbqd9w j /4pxm5 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 bloo c3fp/1tx7c vbd type B can have a child with blood tycxp3/ fc 7vb1tpe O.

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

3.Explain the role of inheritance in genetic diseases.