A man and a woman have a daughter and ajgbi:e:0c )a f w*n(j -c-ilcq son. Their daughter has normal vision, but their son is colourblinl0gqa(*)j iif jbc--:cwec n:d. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human male y32xtqs zy8 pe.3ong/?

  There are two alleles for flower colour in snapdragons. However, th6prhfe1 nr1q*e n( 0uf, x;yabb8xa h6e result of a cross between two heterozygous plants yielded offspring with threeqe*6 6hp fa1b ex b fyhrx10r8unan;,( different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to 8k sxdl gn/( ablfjblx t:3x ,o.0t17ethe correct definition?

  Which of these statements is a cr cpgv/bk l9,u +wb6k)ir8yv( ks7 x,qorrect definition for a gene?

  The diagram shows a pair of a-ht* g;st0sa homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific truw uhbrx1 z* :jb:3 e8dyb) (an1z3ufkait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offhza318un:bku1 x3uw*r()yeb j bfd:z spring resulting from this cross?

  In some animals, the agoutj8fo/ialw* i; i allele causes individual hairs to have a banded pattern. The non-agouti allele jaow8 f*li/; icauses 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 sha h1f w*9af-gsipe in individual pea plants was either round or wrinkled. The results of an experimental cross y1ihs -wg a9f*fielded 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 melanogastotp b/f1h1fthg*9vf 9er) have 8 chromosomes. How many chromosomes are in 9v1g9f*bh t pf/1ft hoa fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromo y+8 wm8 e3iujgj7gl / :r*x1*bsurltosome pairs occur?

The majority of the genes in t074xa dwo /,0rlfdvt lhe human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The dfdr xlvw/4l0,a0td 7 oiagram 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 definiti rng9o-8iqm ,von of linked genes?

  The diagram shows a karyogram of a brown male rat (R7l/b) 9vxhw u-bonnn4w8td *nj v+h( yattus norvegicus). Which arrow is pointing to a pair o7 ut ynbnb9nw w/*(odn-h+xlvj8hv4) f autosomes?

  Mendel observed that there are two possible variations of fl97tg:3 m ,nhd nj.zyeoower colour in pea plants, purple and white. After7den3:mh,yo.tgn9zj 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 bitqjs5ocxg1d mv) .; o+bzefkvnhs+0 6.3k1 xmrth weight of children born in London in 1991.30 b)sg 6 o mon.5 q;xj.hxvekfmt1c++kv1szd

  Which of these traits is .7 6oepzh5/9m jkz+dyaar(bkw.j8 hl an example of continuous variation?

  Which row correctly descuoq 0y.m h58u zg21qrqribes diploid and haploid cells in humans?

  The following table shows the02ahgrv3dp 6ve-*: m6 olog pa diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessiv ju8ejuyc :vh,y5.zu-g ; ru9ue 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 t,ivi78m4kiw r ype A had a child with blood type O. What are the possible genoty riwm4,k8iiv 7pes of the biological father?

  Which row shows the correct annotation of the alleles for blood groh.nod rna )0,lups?

  Which of these statements are .6icfvnea*xstne9:32: i3 f uyfd. rctrue 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 sickle cell anaemia and the) cf*754v is7nencjfe spread of malaria across the continent of Africa. 4sj7vfe7cf* n i )5ecn


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 colouro6n,df; 2.ercj oj- zx is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to one nc 2x zo.;,ejrod- jf6tone (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 ls.yi4 9ktz8nsbna 1nej3i5 em q-(c1and unlinked genes.

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

Sickle cell anaemia is caus( /fnjoljqk-8 ed 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 ;n0hp ;rn )hkxa male cat that is homozygous for brown, long hair and a female cat that has black, short k;)hxpr; 0hnnhair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-s/iofmtw+: 0m bhaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L)i o:wt b+/0mmf 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),*+v (wz+k5cqa 9uxr tl 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 +tku*aqrxw(5vc9z+ lpigs 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 shown in t9hfze j g95oyq/*)l fyhe pedigree chart bz /f)9j5e*9ofhq ylygelow?

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

  Which of these statements about genetic disorders is/dz/ gy.04 z0r xrtx7mhhlxx;(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 trai) 1qv r41n 8n ;m99tq6 jzukgy/hixbuets 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 dnc m/c/ulzb7h3 : /vh9s xi5bthe pedigree chart is X-linked recessivmh h cdnb v u9isx35//l:zbc7/e and not autosomal recessive?

  Different species of living organisms have different numbersrzp pcy8g4 /yl8r 1;vr of genes characteristicr8z 8 cg;v4p/lryp1r y to them. The 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.rdf5.h n8g ju+ If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, whnr ug.h8+fd j5ich of these statements was correct?

  A biological male with hemophilia and a biol8inc ,0 yk,rawo -j-bsogical female without hemophilia have a daughter without hemophilia. What are the possiblejscnob0w ,ak, 8riy -- genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Hdp.atf4+d ,ttelianthus annuus) to see if the genes for seed number and seed shape are linked. The critical value for the chi-squared t,pddt 4 tt.af+est 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 w.asmgqwd9 xwm/, q60swaz:* n ith blood type A and blood type B can have a child with blood /.*w9 nmxq mw:d6wg sz,0asaq type O.

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

3.Explain the role of inheritance in genetic diseases.