A man and a woman have a j6z0z)*+; ,qmigk*wl wxe jm2vbcc)wdaughter and a son. Their daughter has normal vision, but their son is colourblind. Which one of these gq0v cl*),ejw)mkcz;6gi wm +w*jzbx2enotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human male1ymd ohz:3s 12o y/ewv?

  There are two alleles for flower colour in snapdragons.)o 7wvgx4rfb 8 However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explgv4wx b)f7o8 ranation for this observation?

  Which keyword is matched to the correct definiti0 )0/gxm606lw 1;hgh erri4mqw rjutr on?

  Which of these statements is a correct myfq27c 7vj2 tdefinition for a gene?

  The diagram shows a pair of homolo 6j/qnr-odscsj 543 g4kpgx/ ggous chromosomes.

How many loci are shown?

  Two individuals, heten4c.hm 5qzr y(awb yr3o6 jn,;rozygous for a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting f6(3 n5cojy. ,aq zh4;r rbynwmrom this cross?

  In some animals, the agout7k0q, +n mjdxv/vl2 sui allele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single covk +s2m0xvqunj /,d7llour. 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 thaty7 4nt jojmql*j9w n.4 the seed shape in individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrino myjj wn7.q* 4tnjl49kled seeds.

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

  Neurons of the fruit fly (Drosophila melanogaster) have 8 chromosomct,6 gk7 p,dy giswg:.es. How many chromosomes are in a fertili6 7cggg t:kwd,is.py,sed oocyte of a fruit fly?

  When does the random orientation of homologous chromosome paire6 .rf. bsrx26+qbtw zs occur?

The majority of the genes in the human genome have ax o0ulv8mgl6 2wc1b0y1( mnlylready been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one repre1w mml068lv cgxn0(1yuyo2 lbsentation 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 g6 .;o:5h m3kiuvdj rlnenes?

  The diagram shows a karyogram of a brown m :bwbcz,1 /1tju,rf ebjsp: t4ale rat (Rattus norvegicus). Which arrow is ppbjt, /b ,u11fcez: r4s:j bwtointing to a pair of autosomes?

  Mendel observed that thereswqh-rc*o ,a(h7k2g n6)d vus are two possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratd-suogac *7)2rnqhk(sw 6v,hio 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 ofg9x;h lq.(0 /t3dz 4cyxm/5qr lb xebv children born in London in 1991. h0qr b5.z /9 x d;gmcq(xl3l/evxty4b

  Which of these traits is an example of continuous variation,an 687)aqkt ibz5kiv 6x:b kc?

  Which row correctly describes diploid and haploid cells in hd0:wddo0u6zq:9iw tmky 3kld*v .qvm7p/ie 9 umans?

  The following table shows the diploid chromosome numbsbv0 g 0v/htuzfo4 *+her of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessiep, 4sp) i7jxcve 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 cjkxonq) 6so ks1;-;oq hild with blood type O. What are the possible genotypes of the biolo;1-qsok 6s)jqn;xok o gical father?

  Which row shows the correct annotation of the alleles for bloo15 3j g l9xg/0twalzsjd groups?

  Which of these statements r hm.a jsg2b q( i7gs+wb7(fh+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 sickl1n2+ *-g cs su;dawehie cell anaemia and the spread of malaria across the continent of Afriwsnu 1-2;agdhc e+si *ca.


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 przej4ner*wgf *m9walskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an 4g jw*f*emrn9ombre (two 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-6gza. l8:zso:uugn y genes.

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

Sickle cell anaemia i (n/(l.jen0w:qanm t nc ,8cgis 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 biaz:)aigvd6eza ,43 aetween a male cat that is homozygous for brown, long hair and a female cat that hasi3gva )z4,e6zaa ia: d black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped seedslda2*) is27ym sl3wfy v,zj9k (D) is dominant ov7l,yjy3) id2l*w2z9 asfsmk ver 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 dominant ld 9ottyg-;(m 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 -old(; tgy mt9guinea 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 p0h6.ucgb g9 )o-exf zcondition shown in the pedigree chart h- )uoef6 9b xcgpg.0zbelow?

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

  Which of these statements about genetic disorders is-k- n:lrw.n tx7d2 2jng8mmhj/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 shoz3gaf i/-tytpke a 5bg.6ji--w 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 the disorder shown in the pediy ( ho*,e(jhhigree chart is X-linked recessive and not autosomal rec h(e( ,ihjyh*oessive?

  Different species of living organisms have different numbers of genes charactejqkx5vh:i7b, ris q, ih7x:vb5kjtic to them. The table 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 plants, includinvl;uwcm/) d/5x4tjz 5yn0oiqsx s2 c;g flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statemiyozxu xtm;ns0j )4/;d 5vc/qs2 wc5lents was correct?

  A biological male with hemophilia and a b32agq,kl3 yxu 3;obxu w/u(j fc3 ;llxa-p c*xiological female without hemophilia have a daughter without hemophilia. What are the possl;b3x*y akj/ c ou;xx cp-w,3agfllx 32u3qu( ible genotypes of the daughter?

  A dihybrid cross was ca/-ae bz2r3suq rried 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 3earq2-sbuz/ for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A an5 i7ff-fu3dhjd blood type B can have a child with b73djfi5u f-h flood type O.

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

3.Explain the role of inheritance in genetic diseases.