A man and a woman have a daughter and a son. Their daughter has norm.vx (;,d8, hvxfbahnsal vision, but their son is colourblind. Which one of these genotypes could be correct for the biological ,; h8(xd nv,sab vh.xfmother?

  Which diagram shows the sex chromosomes of a somatic cell ins8 bd o)d:zjb( a human male?

  There are two alleles for flower colour in snapud :hcx/np j64dragons. However, the result of a cross between two heteropd: xj unc/h64zygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched tohm,*v f(lo -weyy ;4xi the correct definition?

  Which of these statements is a correct definition foavjdug*,wj) , r a gene?

  The diagram shows a pair of hox29a6d/j ckz /cmrln 4mologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for yi(6f+twx7 gk-ldqp;ckiv2 ;a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspr;pxtcf dyk(g;i6vk-+72 i qwling resulting from this cross?

  In some animals, the agouti allele causes individual hairs tc 7tpzqhd0. /qm 7ff/fo have a banded pattern. The non-agouti allele causes hairs t/qcmp0hf 77.fzdft /qo 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 tzk1ae d2q8 (cj4-stmfxo 7ny5he seed shape in individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105y(8n72 amqet do xf5ck1-s4zj 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 c -et2 fio+l m.z yrsvsim5j).6hromosomes. How many chromosomes ar.2 .eovfjiltr+5-mz i)ys6ms e in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chruewz:knu5:c(+luy;x z 8ym 9 nomosome pairs occur?

The majority of the ;edffc :p8a *d-k( qbsgenes in the human genome have already been mapped, meaning the exact loca8pfs;e- akc (b d*f:dqtions of the genes 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 definitionn-ue9*h6 z ;y)yc/nhb)ygo zu of linked genes?

  The diagram shows a karn).2 oc1 n05nvb zpp3 gpqq.lryogram of a brown male rat (Rattus norvegicus). Which arrow is pc)02p pg.zlvrnqn5nq13 p .obointing to a pair of autosomes?

  Mendel observed that there are two possible variations of flower colouz p pn1-l6:sonr in pea plants, purple 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 panppln :o 1z-6srents?

  The graph shows the frequency of birth weight of children born in Londlm1k de)a jd 8(,6,mknz tgf.ak xqp75on in 1991.qdnatfmk(dze61 , .k5 x a7kp 8),mlgj

  Which of these traits is 8+nym3 ylob- u8dp+ y 4l,ayeuan example of continuous variation?

  Which row correctly describes diploid anr) 8m tog jbt+4lp-;ifd haploid cells in humans?

  The following table shows the diploid chromosomed7w 6gju( r4qa ae(ygad/u6 1jowkgr,g(8xk: number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele*85 xjfw 4j75axgutb8da*bvu)b dvz . (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 blood type O. What are thk09kix h,1h4m j-jm cxk:*onme possible genotypes of m-:0 xkmcx9,1hk kn*jm4joi hthe biological father?

  Which row shows the correct annotatiol9.u f5l wm0brn of the alleles for blood groups?

  Which of these statements are true for q5r tvllr u 3ik6o+ps(uxh,n8 u80y+i 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 spread ofa ext5tsl) 1-z malaria across the contine-t15) zat lxsent 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 determ6n;vje mq)ra ma1c-b 6ined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tonm1j a;va)qr6c-meb6 ne) 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 betweenbhl ,so*of5g3 4wp 9 ns/:d)pt)zvvwl linked and unlinked genes.

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

Sickle cell anaemia is caused by the allele /8 g: 3ff /va,wra19lls(yresxi.yw l 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 arjhv wu+x */q8m1rhs / male cat that is homozygous for brown, long hair and a female cat that has black x1wr8uqm/h/ +svjr*h, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinalvap*5 q(x29 og efxissh6qq8pn/d n5ud9c7x0 e), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dodac q6s0f / v pn79gs(ixnep8x q5o2x9uh5d*qminant 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 tif 4t)k81ugh o,ta5ld 3 lhc+ bcz,4vgo 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 the o lg8act4tbhu5 , l) 1khiz3vco, f+g4dffspring.



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 ofk s qu0:t-1lfx the condition shown in the pedigree chart beltu:lxqk -0f1 sow?

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

  Which of these statements about genetic disorders is/are correc3qd7wlzy,j7je gh ;op1i21es t?

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 pbpjod9 * p2u n1c jotng1p sd.tv,7,z(m bp2)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 thc6p i7 qcb;y)pox3znh2(y / vkkcuq(,e disorder shown in the pedigree chart is X-linked recessive ai3p6n ;)yk cqccq(o zpx v/kub,h(27ynd not autosomal recessive?

  Different species of living organisms have differencqfh3a : ce v794jmv-ct numbers of genes characteristic to them. The table shows the estimated number of genes for five specie34cf 9-7c:q hjvc evams.
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 c5zablk9zyio1ecn ( wxdb 6 (*9haracteristics of pea plants, including flower colour. If the pea plants Menz b5(y1(*w 6lka9dbec zxo9i ndel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophi03o q0dju8jl m)pud2 klia and a biological female without hemophilia have a daughter without hemophilia. What are the possibkjj d p3u)qlou80m2 0dle genotypes of the daughter?

  A dihybrid cross was carries3(z() d kqy*+oi5dw mq+tzwg 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 this iy ()g(w5wdo+imq3 skzzq* d+tndicate?

1.Explain how parents with blood type mldag6 7xf :8axs3wa7vwo+ c 1A and blood type B can have a child with blood type v x8:wwg 7sdmf c1xa ao637al+O.

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

3.Explain the role of inheritance in genetic diseases.