A man and a woman have a daughter and a son. T0roza :b-2udvheir daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biolog-0rz:aob v2 udical mother?

  Which diagram shows the sex chromosomes of a somatic cell in ;o4 c; (oiwnjua human male?

  There are two alleles for flower colour in snapdragons. However, the result of s *xs8uo rizmfx,3 ojm;.pz8)a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most li; zz ,moof8x.isuj) rm8x s3*pkely explanation for this observation?

  Which keyword is matched tob /ilqz3fbm 29y+ha-e the correct definition?

  Which of these statem+cl4anxmt1w6 -b+* k y nv m:oxp1d5edents is a correct definition for a gene?

  The diagram shows a pair of homologousd uv(ea2s )ifb4vcd/ z rycc)ahc 8 ,.kwz-w7, chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trag,d)- snbs 3bj gg:d7g4ocwbj3;x;mhit, were crossed in an experiment. Which row shows the expecw 37bggsnjddb- g3;x;, h jg:mobc)s4ted phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes indivi3 vrsge*n ux6c7/tor (dual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs with a banded pattern. 6xv/eg 7tunr3r*sc (o

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 round o;s3 (c zotuajnmnff9xm :62p -r wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled s n:mx- tj zufsnc( 6;o9mfap32eeds.

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

  Neurons of the fruit fly (Drosophila melanogaster) have 8 chromosomes. How m89xntw2//d5 zkx2v men *oat bany chromosomes are in a fertilised oocyt/ xvnnt5x8z*a wde 2mkb/29ote of a fruit fly?

  When does the random o 3+td ()ann,ybt2mkllrientation of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped,z0h8 nzqz (/*nop6 ;)jwtze zb meaning the exact locations of the geneonn* 08bqz/zj w h6) t(zp;zzes on chromosomes 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 linkqbk(6 yui97n7zu (a foed genes?

  The diagram shows a karyogram of a brown (cb4g/kvzm ,zc1+ dzv.9q q t*.yxnkb male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosom9c ktk4x.c.1zv(dz*g z/yb vqmb +q,n es?

  Mendel observed that there are two possible variations of flower(ml y 9eo5cf(r colour in pea plants, purple and white. After a genetic cross, the ratio of plant(f c 5(oemylr9s 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 London zxd5 h(wfs dn56 lfs7-f*+(xrvl c ,ngh: gc-kin 1991.5,(g--fn kw dv*xhf chl7 s zn6s:(rxgcd+f5l

  Which of these traits is an example of continuous varij)16j*jjnrpo 7gn( pu ation?

  Which row correctly describes diploid and hia:4z(u+v-c -h s lffnaploid cells in humans?

  The following table shows the diploid chromosome nugli(jkl, 2wf 8mber of a range of species.

Which of these statements is correct?

  Sickle cell anaemia i (zh+k3ph )zsas caused by 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 yozaj wgyln.u+w79: (A had a child with blood type O. What are the possi jn.gw9 yw(+luaoz y7:ble genotypes of the biological father?

  Which row shows the correct annotati fnjc(o77;s;vdvbrx+ on of the alleles for blood groups?

  Which of these statements are true fu.k 3;0am dkxror 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 andh on1,djxl jnuyo;8*; the spread of malaria across the continent of Africu ; ;,y*n1oo dhxlj8nja.


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 tj7 :dpu(lh75.sifsf przewalskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre ((l.du5s7jt h p:7f sfitwo 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 and unlinked geneuj:ve yyn87-es.

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

Sickle cell anaemia wr uf)b1kaqmu- *4pw)/lnkj ; is caused 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 a male cy / eaz +xyns9ueot 8tr.9ye.4at that is homozygous for brown, long hair and a female cat that hay9yu8 /e4 anzt. ey 9rotxs+.es black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele z ogx3z4.t0q-p9m xvdfor diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominantq 4txzg o p-0x.3zv9md 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 dor+tkrvkr k u3l k8sjq80bxq o.++x61cminant to short hair (l), and curly hair (C) is dominant to straight hail8 q +x+k tj6.1k rrov8r ksq0+kx3ucbr (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 inheriy0n osx lnumf7,;tt6sl0oh-xd.- xg.tance of the condition shown in the pedigree chart belo l-x.hg7x n-6lf,y sn . m;dtsu0xot0ow?

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

  Which of these statements about genetic disozn;q(ia 1 tq,bksd2wr66rfs , rders 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 traxa(hghjic)wh9; ;*zmits 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 thr+nv 2w2 ;av 5hbrlz+ve inheritance of the disorder shown in the pedigree chart is X-linked recess rrnw52av2bh+ lvz;v+ive and not autosomal recessive?

  Different species of living organisms have different numbers of gj6ei9e zu. 2)43 bv gmq3iaavpenes characteristic to them. The table shows the estimated number of g923aiebvju)p43 m ize. vqag6enes 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 characte7mtbu; wapmcr5v2r02 ristics of pea plants, including flower colour. If the pea plants Mendel was studying cat75c rwmpav;r2umb02 n only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male wichb 54,*dob)mbq f3kyth hemophilia and a biological female without hemophilia have a daughter without hemophilia. What are the possible genotypes of the daughter? q)43y*c f,hbkmo bd5b

  A dihybrid cross was carried out between two sunflower plants (Helianthus anb/: jrz3fqc9eft, 8vbh5hh x1 nuus) to see if the genes xb5/1vrh8fe3 t9ch ,:z bhfqjfor 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 this indicate?

1.Explain how parents with blood type A and blood type B can have/ ;sj6jm7ydrc a child with blood type / j j7;yscdr6mO.

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

3.Explain the role of inheritance in genetic diseases.