A man and a woman have a daughter and a son. ck4qbdid(c+78 x jqm( Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the bi4+djm b7ckq(8dc x( iqological mother?

  Which diagram shows the sex chromosomes of a sov:wxw/-ox ,p ematic cell in a human male?

  There are two alleles for flower colour in snapdragons. Hoz x1+ 18sies4vdpl1scwever, the result of a cross between two heterozycd+8pses11 zx 1iv sl4gous 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 to the correcvtc; b5v, en6tt definition?

  Which of these statements is avycp /of7ue w86/dvp6 correct definition for a gene?

  The diagram shows a pair of homologous ch ; o4z+pnvlnv1romosomes.

How many loci are shown?

  Two individuals, heterozygous for a specifil:cyzay 0i1,bc trait, were crossed in an experiment.zyb0 :li ,ac1y Which row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hai)(hr 7wpj 52ma)qasdurs to have a banded pattern. The nop5u)shq()aw2m radj 7n-agouti allele causes hairs 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 indit2 1sot7uh(.9evwtf3 quj rp+vidual pea plants was either round or wrinkled. The results of an experimental cross yielded +wptr7jh23us( v.q1tue 9f ot315 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) hvft 4 /.cfm2jy 0jus,tave 8 chromosomes. How many chromosome0vu/y, st2 jftcj f4.ms are in a fertilised oocyte of a fruit fly?

  When does the random o0ohfeyk(ymm9 91 rv ;frientation of homologous chromosome pairs occur?

The majority of the genes in the human genome have already;7 fmvvnl4i b8 been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows onev 74nm8vbfi l; 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 defini7o 1tv3m3soyv-d i2 ho8*9zk waef nm5tion of linked genes?

  The diagram shows a k lqtlv s ksy *4*hrhkg/mrr8lp9 3g,9/aryogram of a brown male rat (Rattus norvegicus). Which arrow is pointir 34 pls hgqy/ls*l*tkhr v9/,gkm98rng to a pair of autosomes?

  Mendel observed that there are two possible var1- j;69firnvv 8hrkn viations of flower colour in pea plants, purple and whit;fh rvni6j81v9 v-nkr e. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of children born in Lon +vxk o7t s71yaww,u7jdon in 1991. ja s ,+77 oxyvw1uwt7k

  Which of these traits is an example of continuous d 1;tg/ vx3rq-zbg qs1.njyq :6 nvd-+b6bcjjvariation?

  Which row correctly describes diploid and haploid cemoedy -yr 5r*73gbma(lls in humans?

  The following table shows the diploid chromosome number of a range of specioyx9wnc u-uw,n7dg3 -es.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (Hj1v1t dp2gjs/6uo ote4;h3g lb$^S$). 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 O. Wulhkl*--ewy: mz+)nbxqv0g) hat are the possible genotypes of the biological fathe) xq+n*)ym:hlzlbv-ek- gu0 wr?

  Which row shows the correct annotr6+j.j3wccq 3p jdrt +ation of the alleles for blood groups?

  Which of these statements are true for alleles?nt; xalen( /kw3ui,3z1 o2tv ah oqh7(,qhl.u
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 of mq k.m0bslu(cg5ha fxj0 z0k7 /alaria across the co0/.0ju0q ghcmf5bal7sz(x k k ntinent 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 coloe +/ j:bbtnzcjn (m +r:6.rnzpur is determined by a number of genes. Brown colour (B) is dominant to s: ectmnzjjnp (.b n rr+:6b/+zandy 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 llt.w g+yj 1b2rinked and unlinked genes.

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

Sickle cell anaemia is caused by the awjco fz tur92th-v hgp5,. 4o)llele 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 ho1+(s- iqs9r42 izm:a to+tnj/v vjwwomozygous for brown, lon in tjr2zv4-vtoia9m/(s 1+s w+:ojqwg hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for df5l4rax)m* c sc9co t1iamond-shaped seeds (D) is dominmco tf9cx)l1r4sac 5*ant over oval-shaped seeds (d) and the allele 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 porcellus), long hair (L) is dominant gs0 q,zd:sm,b vyu,3pto 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 ,3ys b sp q:,mdgz0v,ushort, 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 yld o8,g +m8teab )2xcthe pedigree chart8ymo ct +eablg)x,d82 below?

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

  Which of these stateksx2 +bwpv1q; ments 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 distribupmxv hs6991ztqz+yq ,)ls jr 4tion.

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 chartm3mtrfc1lpcm2;fj jtug4( e *q8+4mv is X-linked recessive and novq4 *tc4f mfl +;mt1pe umr2j(gm3c j8t autosomal recessive?

  Different species of living org ,i)s 7*msvrou0dk -cuanisms have different numbers of genes characteristic to them. T *-u, dski)omcrv us07he table 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, including flower colour. jz)hh- 7bfyx5.,s kz zIf the pea plants Mendel was studying caz,hx7.h z5)js fkby-zn 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 bioloko4 (kubeu5v- aol5;z gical female without hemophilia have a daughter without hemophilia. What are the l o5- vukezbu(;k45aopossible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Heli:txl3 ao saf+xn8ur,5b5h z+irgi 8+ianthus annuus) to see if the genes for seed number and seed shape are linked. t5bxa+:ign5suha+,l 8rzoxi38i+ f rThe 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 typyk l8,(1+ruh+ yyqyeae A and blood type B can have a child with blood typea1y(khq u,8y ly+ ry+e O.

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

3.Explain the role of inheritance in genetic diseases.