A man and a woman have a daughter and a son. Their daughtvgzhg itqh61y1h8t8 c6tf1u 8 er has normal vision, but their son is tyz8t6 f11cgq tu8h6vig 8h1hcolourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chrywwr p4-prkoy5+. t:tomosomes of a somatic cell in a human male?

  There are two alleles for flower co ybjvabx3mbt/(). wlmgy1c,po;0 jo7jdc ,c3 lour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring witjcb0a),y (ycc,3xtb1w bg /pomlj.v 7j 3;dm oh three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched tog:86uqbepz81 5p rtoo the correct definition?

  Which of these statements is a correct yj1q4n0hh1zn3f ioqq7w. 0ce definition for a gene?

  The diagram shows a pair of homo8 )svqikdy0 y6emb yp213 c:uelogous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were*2zm71mg,gsr egz j:h crossed in an experiment. Which row shows the ej7g *,sh mmg:z21zrgexpected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs w0xoihe e3wl+ffzau7u/5;7 l+nf w3hc5nt-v to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Indivihu33etc w5wz w-l+5iv7noff e;f 07alx+u hn/duals 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 individual pea plants was either rouniu62l9 xr xix8v asfs*zxv+ 7 i/cfd)6d or wrinkled. The results of an exp/ 8ia fss2d9 i*7xivxxcfur) 6 6zlx+verimental 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 (Drosophila melanogaster) have 8b,q+x3uede d .+emqnz* *3gqd chromosomes. How many chromosomes are in a fertie .dq33+,z + emdq*egd*nqbuxlised oocyte of a fruit fly?

  When does the random orientation of homologo;*ktc 2eubsc *us chromosome pairs occur?

The majority of the genes in the human genome have already been mapped, meaning-07*of wbuy zw the exact locations of the genes on chromosomes are known. Tuzb7 ww*o0- fyhe 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 d,ajzg58 ke+r+ys /9v h)cypv;.kro eaefinition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus n j9 hses13v2bxorvegicus). Which arrow is pointing to a pair of autsev29jhx3 1sb osomes?

  Mendel observed that there are two possible variations of flower colourud4cj;/b --ln4qqlm n in pea plants, purpl 4 uc;mlnq4q-ndj/- ble 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 weiguc q12 0y lgg/ul;vu;nht of children born in London in 1991q ;u v g2l;gyn1/ulcu0.

  Which of these traits is aj mbt*,y/ eh95 pwm-njn example of continuous variation?

  Which row correctly describes diploid 4fa:e* 6giv bjzoj5c7and haploid cells in humans?

  The following table shows the diploid chromosome number of maovx+r*ax 49 a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused + s 9l.2n thyugmhh)6-dr/odyby a recessive 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 hn3 mei tv6.ph9ad a child with blood type O. What are the possible genotypes of the biological fatherv6 ent 93p.ihm?

  Which row shows the correct annotaqdjeq70al .7r tion of the alleles for blood groups?

  Which of these statements are tr.st6:c lwjzbp6 t2r. cue 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 sicklr6w51f ak6 mmci6(.pbeb3 d mle cell anaemia and the spread of malaria across66frpb me wib6k.5ca l1(dmm3 the continent 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*a46 f1qt 74 bvl.fln zymk ik)bim-pb7sr4i 6 by a number of genes. Brown colour (B) is dominant to sandy colour (b)a64z 74r7.plyf tn 4 *fb)mlmb6v-iik1q ibks 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 andl(4z kjcil2o2k/5/ c lkme p5u unlinked genes.

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

Sickle cell anaemia is caused by thegii-/rne6/ s4a zqv ba kj+8r5 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 s,zk3z hek 29ahomozygous for brown,k293azzhes k , long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for52ofcp*p- gjkf- cm1a diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele fmf*-j k acf15 pp-cog2or 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 to short aqm1 0l +3a;znted hz3hair (l), and curly hair z;30 hmt l3aedanz+q 1(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 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 shoo 0o3vx3ssa1 :rk5zl nu8:vod/ p-leawn in the pedigree chart be0la1v5r:o 33ea:nplo ksux -zov 8s /dlow?

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

  Which of these statements about genetic dv s+ tz/:ic2cgn+ x,hmisorders 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 trait;b2p2 f4 h ;cx7dmppuvs 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 the disorder shown in they:2s)erx ;rd/7c )g +qhtekcy pedigree chart is Xexqg)y: +dkrhy/ 7ctrcs ;)e 2-linked recessive and not autosomal recessive?

  Different species of living organisms have different numbers of genes cfkm-5a- tcfrw dvl(3e5gg *v)haracteristic to them. The table shows the estimated number of genes for five species.kw( fdg-cr m)*vg-v5l 3 5afte
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,ltt9a)7k8wm g 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 these statements )7wak8m l 9gttwas correct?

  A biological male with hemophilia and a biological fdk u-6x;htk ec9i1af hmn5.p; emale without hemophilia have a daughter .9 n;-hxh6 ;iftucakk 5p1medwithout hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carriexrr/ *k9t*qknemr;(ibt64 ayt;yyz umtg:;9 d out between two sunflower plants (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; what does 9 (rrg/ y4;ktt zt a**mtiy kn6 u;qye:x;mr9bthis indicate?

1.Explain how parents with blood type A andz/d tw1n )4khdj jb,p. blood type B can have a child with blood type On wb, k4)j1 j.tz/hdpd.

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

3.Explain the role of inheritance in genetic diseases.