A man and a woman have a daughter and /na:0hk9b :yzdg)2 pq8v jva xa son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be cor:bpvyx:98nj dv20)ka hazg /qrect for the biological mother?

  Which diagram shows the sex chromocn(v0.mgr *kt somes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. Howe/t hicb ii++ +aurb -m/ps.8kdver, the result of a cross between two heterozygous plants yielded offspring with three dif-d +.i+rpu8/ c timb+kibsha/ferent observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the corrjhyiz*p ,uuv4 7.3 hhsect definition?

  Which of these statements is a cl+w;fm h)hh f7orrect definition for a gene?

  The diagram shows a pair of homologous chromosomgsy586a l+32a ok6dw8zb tx epes.

How many loci are shown?

  Two individuals, hetos)sed md a4:p2 4c4amerozygous for a specific trait, were crossed in an experiment. W ea4adocm2m):ssdp 44 hich row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causmn )vw5p ibs*.es individual hairs to have a banded pattern. The non-agouti allelwv* pm).b5ni se 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 individual pea plants wasm uixcs rfp/u 5tu:;05 either round or wrinkled. The results of an experime rc ;ut/fm0x5:upuis5 ntal 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 8 cll9od/0 r/3ovd bwch4hromosomes. How many chromolcl34o0wd /bvdh /9r osomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome pairs g/yh2e 5aj5m* w xagf*occur?

The majority of the genes in the human genome have already been mapped, meanin kao,.4tlnm f+g the exact locations of the genes on chrolo+tkf.,mna4 mosomes are known. The 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 definition of linked 3:t/ vr r/fsqsd(3o fugenes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Whide q/ynr-k05bmwo5 1 ia: ehy*ch arrow is pointing to a pair of autosomb:o 5kaw5r- nyihed/y0emq*1 es?

  Mendel observed that there are two possible variations of flowew*f)g,j;lba8f 6h btnr colour in pea plants, purple and white. After a genetic cross, the ratio of plants with p f8 n6,*t;abfwh )lgbjurple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of childr -wxdlrl0viouw );o )1en born in London in 1991.i xwdlo-ol)r)uwv ;01

  Which of these traits is an example of continuous variatif*tf3t u z.wj.on?

  Which row correctly describes diponjm769o ).imhrb9 k1ervv;d qi 4se0loid and haploid cells in humans?

  The following table shows the diploidv2rx 3;1sd cvs y)y/ya chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by 8 zbvve j*,lx l(w 203qqt.ikba 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 had a child with blod x a*uw:k* ywc; wl0d( 09wbmgg1l(wvod type O. What are the possible genot k0wwlbdmx ;l0ww *(g1:vu*gc ayd(9wypes of the biological father?

  Which row shows the correc86ljcs: b hgx2y acl1/t annotation of the alleles for blood groups?

  Which of these statements are true for0.(zkpci9y+eq jw y c: txnaxf3+:qr1 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 spreapwnxw agns2uhkg/o4c5p9h i u/)a08 4 d of malaria across the continent of Au/ uhn)4/a hcgip 5w80wk9npg xsao24frica.


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 numbesuk5o,s;ie 2 lr of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to one tone (puis;sk 5 loe,2).


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 uy)bmsc2 yck:5nlinked genes.

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

Sickle cell anaemia is caused :kowwt)9nu ,w (mrh*tf mo +6cby 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 homozygo* c)vl skrk5 d9f9:qdsjvg+/ yus for brown, long hair a+q5*9 kcj9/fkydls svv gdr ):nd a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Tarax(ppgk 5z.-gm9: g6ggw st x1sdacum officinale), the allele for diamond-shaped seeds (D) is dominant ov5zx6md1g. g( -gts gkp p:gws9er 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 dommzqu* )3;h bniinant 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 thi3*nzhq )umb;e 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 inheritanc2 f/e3al;x mnje of the condition shown in the pedigree chart belowmejx f /l32na;?

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

  Which of these statements about geneti/*s19 tlpvuen f0 rdsn/6n/ijc 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 distributio vv1r(3hlh)l on.

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 s-w4a nuc m8rosa31 xk8 qm-ko/hown in the pedigree chart is X-li-oocw a4 /smk1nux8aq m-8k 3rnked recessive and not autosomal recessive?

  Different species of living organisms have different numbers of genes:uuu6yb 7g el0 characteristic to them. The table shows the: e7ublu0y6u g 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. If (c4m;vlsussqc*9 y 9y the pea plants Mendel was studying can only be white or purplqslmys(9u *;csvy 9 4ce and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia andw:s 4.som3y/1murh a)/r xtur a biological female without hemophilia have a daughter without hemophilia. What are the possible genotypes of )shmswt/4r3xm 1ru/:. our aythe daughter?

  A dihybrid cross was carried out between two sunflower plants (Heli* r6l9mu0k,bgd ;syk ganthus annuus) to see if the genes for seed number and seed sha0*96sylg,m ; dk rukgbpe 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 this indicate?

1.Explain how parents with blood type A and bcvp ,a7- fh.oslood type B can have a child with bloooh pcav-.7,sf d type O.

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

3.Explain the role of inheritance in genetic diseases.