A man and a woman have a daughter and a son. Their daughter hams t) )ldha. b72ka;u:cw-w gps normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biologica :a7lmwag kphdsw-)t c;u.b 2)l mother?

  Which diagram shows the sex chromosomesxo0/ rzmv2ck4(mipr 5cnm . o8 of a somatic cell in a human male?

  There are two alleles for flowi p2 gqkanm/13er colour in snapdragons. However, the result of a cross between two het2p/ imkg aq13nerozygous 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 tod2yhiv,qy1 im:c -e/ f the correct definition?

  Which of these statementn( h qg3)eynt- ktud-.s is a correct definition for a gene?

  The diagram shows a paicj9 z0cfzz w buuu2(u4 3oqr).7w1xit r of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were cm vtf7;(j.eryyffy j6rky)4.rossed in an experiment. Which row shows the expec7..f)(ymyjkvt ffr 6ej;4 r yyted phenotypic ratios of the offspring resulting from this cross?

  In some animals, the loa- o e(y**hkagouti allele causes individual hairs to have a banded pattern. The non-agouti allele causes hal yhk-*o*eoa( irs to be 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 in ind2l-a*u p1ce rbo, xv7dividual pea plants was either round or wrinkled. The results of an experimental cross yiel7xaecl, p vbo*d-1ur2ded 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 (Drosophila melanogaster) have 8 chromosomes. How many - nf hgd8)oyt:frw-8hchromosomes are in a fertilised oocytehth- :yd-rn)f 8wgf8o of a fruit fly?

  When does the random orientation of homologous chromosome pairs occur? 6s)jb dt xnc1+izwt)4l4znb8

The majority of the genes in the human genome have already been mapptfh,e gs*/+i ked, meaning the exact locations of the genes on chromosomes are known. The diagram besht,if/+ k*eg low 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 correcthgt nko:sc 5xb. 2t+kc+u5e n4 definition of linked genes?

  The diagram shows a karyogram of a brown,, w)+dwn7syadql d /d+po7xz male rat (Rattus norvegicus). Which arrow is pointing to a pair of auty)7 ,7ndds , z /opdw+aqdl+wxosomes?

  Mendel observed that there are two possible variations of flower m vbs0 n 2yofg027w1lmgdte*) colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1. Whasw lym 0d0*gn2mtog fe7) v2b1t were the genotypes of the parents?

  The graph shows the frequency of birth weight of children born in London in 199w2,nde/3wmlm9 s a*o y1.m,nw a3l2* emsod9w/y

  Which of these traits is an exab avo)3knf3l* mple of continuous variation?

  Which row correctly describes diploid and haploid cellor *7b 8,5urlli9t pfks in humans?

  The following table shows the diploid chromosome number of a range ofjysv0rj*eg 2 v5*ei p- species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive +- ou.mw-calq 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 type t8*w;r,9pb) mwocbe i O. What are the possible genotypes of the biolog9 ebo;im*8cprt wbw, )ical father?

  Which row shows the correct annotation6 *teuynby,h0 of the alleles for blood groups?

  Which of these statements are true fodq4)l 8 zw1 qb9rzg8 dc*pc;ztr 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 spredjw xokg 2bz2 *bm/-r fqb9y.;ad of malaria across the contin*/f2jmq wxb.bo 9-y b d2r;gzkent 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 det-c)m lap(p8 u6;djm: tqj)x2eznyek intj7 ; .ermined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tp )d2e njk8c; l t)tmn:;y7jmjzqax-u.p(ei6one) 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 unlinked gq5 fqyc1,2 kbgfqi ,2ienes.

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

Sickle cell anaemia is e khzfhvjo4ihhy( 5-t3/u2at/ uu6c ,caused by 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 homozygous recdxc;d3) s;for brown, long hair and a female cat that has black, short harxe3 c;cs)d; dir.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamopp twrqhf1k8in f626r 97u b7*oya w(qnd-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short seedst6 o6khbqpnff9qarw ur w718 y2 *(7ip (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 (l),b3,/o m+ ga9hrotuby8 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 carried out on the offs,uayb+ro8g/ b3mt h9 opring.



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 show nwck*vubdbu5.o*2 y 6n in the pedigree chart below? yoc u.wvkb2* du *65nb

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

  Which of these statements about genetic disorders is/are cokzjf 69d1ez- x qc(;yorrect?

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./qs(c1r bwox1 g7r ww 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 inheritanc7pux *4v tlqpov4 ja;)e of the disorder shown in the pedigree chart is X-linked recessive and not atv jp74;up)*l4 av qoxutosomal recessive?

  Different species of living organe m8tny *oy4zw(tniu3a0yi.7isms have different numbers of genes characteristic to them. The table shows the estimated number of g.ie(4m n*y 87yayunoi0t3w ztenes 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 characterir uj9thm(cc8k,zly *0 stics 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 th(kt8, umyhrl *9cjz c0ese statements was correct?

  A biological male with hemophilia and a biological female o x*wg1m 9y7akvz f)5suyy. 3msft/n-without hemophilia have a daughter without hemophilia. What are the possible genotypes of the dawzam*xgo3-.7uy )/5yff9 n ymksv1t s ughter?

  A dihybrid cross was carried out between two sunflower plants 9i.ovrlsquxw2r plnik-1yzc ,**j , 9 (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 calculated value for the chi-squared test was 10.05; w2kp-*vr1 9ulos, ,qnjl i9.c *y xrwizhat does this indicate?

1.Explain how parents with blood type A and blood type 3hq*)wutc,z/6 q *z h hg8nxo *hd+ys4 ,nrjncB can have a child with blood type O.) jsx6hzo*nh qq*nh8z+4cny*d hr3guc t ,/,w

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

3.Explain the role of inheritance in genetic diseases.