A man and a woman have a daughter and a son. Their daugh*u .-dpxnam1 bt n86sixuh8 1njvm -g0ter has normal vision, but their son is colourblind. Which one of theseu 0n-un1nsxip6mx8.gb- t a d81hjm v* genotypes could be correct for the biological mother?

  Which diagram shows the vvqg/lkr +x. ote:v8+ sex chromosomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the res;l-s +ct nr zvdn7n1doq/9x( wult of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanati7(-nn;w qxno t ldrdv/9+1 sczon for this observation?

  Which keyword is matched to the correct dy,6g-2; kkag m;lukve efinition?

  Which of these statements is a correct -6g;,z tjn //d 2bcjnie6zlk(lpo2og definition for a gene?

  The diagram shows a pair of homologou( yfhg 5ga)ot/oupv*)s chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a spe b, twxs9 em/3e(3ysphwh l)8ocific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offsp/3s8tohbwe,m l 3h(yxsew p9)ring resulting from this cross?

  In some animals, the agouti allele cau/ff2(hkg v;xfjs-z 4ros(z:. b yz qk7ses individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals whohvrs/o g;4 :-fz (qs(7kzzjxf 2by.kf 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 individunt7 0pd tdr5n0al pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wdnn57t pd00trrinkled seeds.

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

  Neurons of the fruit fly (Drosophila melanogaster) have 8 chromo92sw i;/l-y3zic psknsomes. How many chromosomes are in a ferkws3ip l92 zi-;s c/nytilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome ano;di 5zr5l6hh 1x a(pairs occur?

The majority of the genes in the human genome have already been mapped, meaninefqo o*y lj(72g the exact locations of the genes on chromosomes are known. The diagram below shows one represent2ooy* l7( eqfjation 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 e*f q; u-kw 5g49xvqzaof linked genes?

  The diagram shows a karyogram oib 30h0 quse/oidk0.af a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of autos0abd.ou qh3 0ks0 /eiiomes?

  Mendel observed that there are two possible variations of flower colour inko* h:w a /nziljn;;n2 pea plants,2zao;n: ln k jh/nw;i* purple and white. 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 bornqdw.5n kdhwo12sek 49 in London in 1991q4n.ek2ds 1 ho9k 5wdw.

  Which of these traits is an example of convf dr ja8nmx46qp.2g 1tinuous variation?

  Which row correctly describes diplo(42;uubj szneid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of speciesub s yj*)k1*p uz*pke3.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele v6+rwer8wg6t lb1erb, *k 6nd (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 chik20x3igwxh5 f t4m d*kld with blood type O. What are the possible 5w0xk*xk 4hm3di g2tf genotypes of the biological father?

  Which row shows the correct annotation of tnj(6uy 17wic u 2byp,the alleles for blood groups?

  Which of these statements are t tb9h72rpiz t*rue 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 s8 nherw/4.t 1;yjc haeickle cell anaemia and the spread of malaria across the 1/te ;j.8whaycn r4hecontinent 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 s/fxws4drk0x*v+ k p8number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (Prswx8dfx+ vks4pk/ *0) 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 unlin/jwza2 c: peu+ked genes.

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

Sickle cell anaemia is caused bjbjsp5 5 4s5t(utmj*aq,slk + y 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 cru5rjv;j2 ya-hoss between a male cat that is homozygous for brown, long hair and a female cat that has black, sh;v-yhu rj2ja5ort hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum 4/8xx 2 hthx jsashk20officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for losj8/s0kh 2xt24 axhhx ng 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 d 74dxc4 b1fxkoominant 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 (χ2) was carried out on the offspring4dkfc4 o xx7b1.



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 ch b6b.n+blk(qeart nb+.bqe6b(k l below?

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

  Which of these statements about qcwe 0ofg.rqfx 9+91z mp7t5k 6e4qhtvxl/r 7genetic 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 c,xkdswq/.m7axzwcp loo :; wq;9 d16man 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 disorderrz,meaf)30/ w-, x;-t.wrv vuhbiec h shown in the pedigree chart is X-linked recessivr3e xt.mri- ,ubv/ )hezc0; v-,f ahwwe and not autosomal recessive?

  Different species of living organisms ha+ j *ex/axinc5nqu74aas g37h ve different numbers of genes characteristic to them. The table shows the estimated number of genes for five spec3njxae4 xa *+5nhci s7ua/gq 7ies.
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 prix)r7y 6 ie3yea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow67iryrxi ye3 ) the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biologicalud+;rbieq7/lg5i g vp 37qws- female without hemophilia have a daughter without hel+ 5eq37 v-pgqr7wu ;idbs/g imophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annuu8q2*./l lbg vv5h2qhx, rha nvs) to see if the genes for seed number and seed shape are linked. The critical value for the chi-squared test at the 0.05vl qv,*xh8haglrq2/ b.25vn h 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 typ kyku .s;in6;esz3e0 we B can have a child with blood type O. ;usyi;3kenwe6 .sk z0

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

3.Explain the role of inheritance in genetic diseases.