A man and a woman have a daughter and a son. T ps ch4 5yvv+v qaem dq()9tgnr7qeywto.,;; 7heir daughter has normal vision, but their son is colourblind. Which one of these genotypes c7r 9 q5t+ qnyvag7(hqp;4eewd;ty)o,mcv s v .ould be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human male?2iiys74koo ,e

  There are two alleles for flower coy)g6ed0 szz,n;t0iu t .gvdt;lour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspry 6)s;de;0d g,gz tvu.n0titzing with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matcn/cl)yfo+n( gw31bcrpgq / 0fhed to the correct definition?

  Which of these statements is56hfnss5b7y 7zm n9rv a correct definition for a gene?

  The diagram shows a oryj2 sq ;s1* re+erj5 m2z9d5 yotx*fpair of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trap 7*, or4fxg5qzhol3qb- )ivk it, were crossed in an experiment. Which row sh5ripxb,*o 73qzk q-4lhgo) vf ows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a bandedl*3.sj wr*. h* hh 0kaebq/bgl pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous havaw3.h sbq/ hge*jkl b.0r**hle 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 rounptbp( tu 110nyyfj:6x g*+satd or wrinkled. The results of an experimental cross yielded 315 off u6t+t*a11y b(nf sytj0pp:gxspring 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 chromosomes. 22er hjz2xwu 3How many ceuxwrhj23 z22 hromosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientati3 p vvj8u-g)2zhadg;r on of homologous chromosome pairs occur?

The majority of the genes in the human genome ybjqae-3(nq 2 igd)s7have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologouij 2e3 ga-ysqq)n(b7d s 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 genes?nuhmc0 *bv5*p no491qe,r xxb

  The diagram shows a karyogram of a+)k ok29( pdl e,g2ulbwjn(za brown male rat (Rattus norvegicus). Which arrow is pointing to w9uzljo(n pgke+ (bd,ka )2l2a pair of autosomes?

  Mendel observed that jlf gwett(cjjw+1208t ;;pbuthere are two possible variations of flower colour in pea plants, purple at j0 j2u;et;8cpw+ jfg(w1ltbnd 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 chil,;yksjth7n /p+fmxi . t z(k6rdren born in London in 1991. mp t 6(/; hk tsj,irzf.+xn7ky

  Which of these traits is an example of continuous variati krmv3 b/y ;ib7yt 1sezq8.xr7on?

  Which row correctly describes dip .+zmwui(ywve3sm)z4 loid and haploid cells in humans?

  The following table shows the dim*/jx. f0 1kcg .zsrf 3xqn5jkploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allvb f1yu*a*xthhl06 ;kx 0,n gbele (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 witwn t(h kh4ayki1f /8q-h blood type A had a child with blood type O. What are the possibl1nk hf i4y/kq-htw8a (e genotypes of the biological father?

  Which row shows the cor-:xqc:q3zxgzzow w ),rect annotation of the alleles for blood groups?

  Which of these statements are l nj5la+pj2wwzt,nyok58w )dw *u;w ;true 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 tv9nx, q.ui. ha)usw;sickle cell anaemia and the spread of malaria across the contine)hivt u .,uqwa;9 xns.nt 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 1g)+fc.tj7 kzf y1fmnprzewalskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is d+tk1 yfn1cfz)f mg.7jominant 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 linket .nsqzb(n5 gj u+:rr1uspx5 1d and unlinked genes.

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

Sickle cell anaemia is 3+ysm h4y9e hfcaused 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 cat that iue1w0r h7ulbsns9iq)r d) n1)s homozygous for brown, long hairu hbsq7) url0 dn1nwe9r)1) is and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped se2en:y7le7wgm eds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over shoyw7m eg :72nelrt 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 shorti2ml 0 dfp0*dv hair (l), and curly h2*0lm idpv0 dfair (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 s / ibh:g2ubjhs8)2qe rib sv83hown in the pedigree chartbe r:sjgvq22/883) uhbibsh i below?

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

  Which of these statements about genetic disorders is/are correctjz v:uu13u-uq?

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 norm*h0 n xcp6sna,u ,-pweal distribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  What suggests that the inherita+r36guy *s l/gtr/uirnce of the disorder shown in the pedigree chart is X-linked recessi*u r+l r3ir6sugy/g/tve and not autosomal recessive?

  Different species of living organisms have different numbers ofxuxcb y7 *oh eljy19o+):*uwv genes characteristic to them. The table shows the estimated nuvb* yw*yj)uxhoo9ux 1ce+ l7:mber 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 plantsu /pjp0avfi20 t pzy:tg5 x-/c, including flower colour. If the pea plants Mendel wasvu ya/xz2t-0g0f jipct/p: p5 studying can only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophfin1/1n cz6 1db4yl8nmjc;iyilia have a daughter without hemophilia. What are the possible genotypesc 6yn;8fm/iynzj c11bd nl41i of the daughter?

  A dihybrid cross was carried out between two sunflower plants ()iux j-fag *j,)0ciceHelianthus annuus) to see if the genes for seed number and seed shape are linked. The critical value for the chi-squared test at the jje )cac)g* ,-xuii0f0.05 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 hav qq99p**t,xn alibl( ae a child with blood typi qna9lq*b9plxa, (*t e O.

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

3.Explain the role of inheritance in genetic diseases.