A man and a woman have a 30fwp59hyez ki*(mxkxl5a2 i daughter and a son. Their daughter has normal vision, but their son is colou3mzl ka(e*f9w525 xxp0yi ikh rblind. 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? nz..qu fb8v w zu8 jup*33lqq4

  There are two alleles for flower colour inxsm ,,en6v,b5wd;wxu+w:n i v snapdragons. However, the result of a x:xiv 6 n nbv+,wwsw,emu; d5,cross between two heterozygous 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 matched7ba-y pf.np x/ to the correct definition?

  Which of these statements is a correct definition for a gene?6gc+hyh(6 1wfpogd jx/q s r1/

  The diagram shows a paf0bm c91ad,n ;g: uhr9h1nngzir of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygi e3u)8l7 wwk4k o+nqxol3b 0qx;uh/ rous for a specific trait, were crossed in an experiment. Which row showo kulqk4wwux80i;73nhr)b+ 3l/oqx es the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a bandm*rb7w.1-ipgm 3-y rmni6bt ked pattern. The non-agouti allel-gim*t6wr-3m b 7rp 1mk.bniye 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 was either rouqnx.gj -:oe2oled0r w y/) 8kand or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled seeds. qdgy 0 n e/ka:o-x8.jow)e2rl

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

  Neurons of the fruit fly (Drosophila melanogaster) have 8 chbxtk1( g+lx .ce e9hn.,rg cpl4ao63rromosomes. How many chromosomes are in a fertilised oob lr.4,x a3kc9ege.hg+ n6r(co1tx p lcyte of a fruit fly?

  When does the random orienta8jpzh+bb pln2yg98 j.-s,p6rnl tfl+tion of homologous chromosome pairs occur?

The majority of the genes in the human genome have already ,b fmpapf,yz uh( x3:5been mapped, meaning the exact locations of the genes on f ubaf, 3:(5h,mpzyxpchromosomes 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 definitil5 i4e86xrjgzon of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvfvpspvjk((s n 6h b443egicus). Which arrow is pointing to a bs3pfh4k psnvj(v (4 6pair of autosomes?

  Mendel observed that there are tu5 t5nxxlh).gbjd: 4*py1l wiu m4ch5wo possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1x yp4 5b51g)d:luu 5h lh*.wtc4i jnxm. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of cl;v8ku mk( bv0hildren born in London in 1991.ub vk8v; m(0kl

  Which of these traits is an example of continuouvd9ubf ;er c; 4ja:ye w(vh35ls variation?

  Which row correctly describes diploid and haploid cells in : jk(07-ye2lxb ))ih /dpal/fts 3pkfaue. zwhumans?

  The following table ski-5 :n e yqsxbxd(jpjs q- 03+km(a,shows the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is causeda80xf a:9 tghh+py:f)knje ej6ne;bwo1+v 8d 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 A had a crx)efihebfo z x+60w)fec95 2 hild with blood type O. What are the possible genotypes of the bio6cz2)fw )ox9f+ex5brf hi ee0 logical father?

  Which row shows the correct annotation of5;dsf7p he5tx the alleles for blood groups?

  Which of these statements a6q7jql xm da/nk,:s1 are 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 sickle cell anaemia and the spr741kcogotz m :ead of malaria across the cmzooktg: 1 47continent 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 determined+l9e :jbg/vbu d4c v:v by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (twob+9:j /vubc v :4vldge 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 anod ry1g+q*7or d unlinked genes.

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

Sickle cell anaemia is caused by thhocb, ay2es0cd t:m(+ tf +.ufe 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*v +gqwokpc+ l*jq* k( homozygous for brown, long hair and a female ca+klc k*ovj*g+(q w *pqt that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped s+asl+ edwjwb0t.8m8p 0pi jl/ eeds (D) is dominant over oval-shapejw p8+bwp0 /l0+.aedl8tji smd 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 domiu+izt. av20ket(n0j d nant 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 carrjevd2 0utt.+ai0 nkz(ied 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 wei : x5le3izu+d;y3z shown in the pedigree chart below?5z+3eli3d :ei x;z uwy

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

  Which of these statements about genetic disorders is/are cordr/4ig dnkq (a(o8 4phrect?

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 cr i st,6ly-g9ean 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 the24l*t(*v89qm wwr user invc+ disorder shown in the pedigree chart is X-linked recessive and not autos i89qrtc *e4lrvsmu*(w nv+w2omal recessive?

  Different species of living organisms have different numbers of gen3offrdn:5r /j es characteristic to them. The tablenfd r/5o3 :frj 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 plant 9ionl5c)i+bs-6tdx1ayws s0mc it ) ;s, including flower colour. If the pea plants Mendel was)c+ wi s 1-n0y)5lcmid9tsx ta;os6bi 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 andffc*x l*5jj2 /mmg9lvt.dku fu.te 2/ a biological female without hemophilia have a daughter without hel/l 95ktgjc j.*mvux 2tdf e .m/fu2f*mophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between tw;1h/qmt st8id o sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical value forqd;/ih 18tts m 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 a child with bds-b)ymoh)* klood type Oy)k)*obhs - md.

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

3.Explain the role of inheritance in genetic diseases.