A man and a woman have a daughter and a son. Their daughter has normal visio pu8djgkm2 3c*n, but their son is colourblind. Which one ucj2 mdkgp38*of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human ma0:gkg+l :j nvfx4e6wvle?

  There are two alleles for flower colour in snapdragons. However, the result ob )/jkb5ms5o ehmni8m 3f(-if f a cross between two hib j-)s 5omk i8(meffb 53/nmheterozygous 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 to the correct definitt a /*uahy +vho3+fa(aion?

  Which of these statements is a correct definitiofjh2:si7 rbmcx562dgn for a gene?

  The diagram shows a pair of+- quj0ru09,dpbus3 w0e orjr homologous chromosomes.

How many loci are shown?

  Two individuals, heterbnf tzh+vmb.c81qp . /ozygous for a specific trait, were crossed in an experiment. Which ro+ht8nbpv 1qb / z.f.mcw shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to havx2ziy );hkt 2je a banded pattern. The non-agouti allele causes hairs to be a single colour2;y2hij )txkz. 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 eitheaihb1yg2 ,ven zh4g/e9ev0l+r round or wrinkled. The results of an beale9vh zy,4 1h+n/vigg2 e0experimental cross yielded 315 offspring 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 chro xl6hh;sy( 9wtu+wp1je:i 3k qmosomes. How many chromosomes are in a fertilised oocyte of a fruit w1xs3y hewt(6p+lkhqi :9 ;ujfly?

  When does the random orientation of h5a xlw v-bjpyl-, ).fjomologous chromosome pairs occur?

The majority of the genes in the human genome have already been mapped, meanify.m 6j: f1obcng the exact locations of the genes on chromosomes are known. The di1jo:b ycm.f6fagram 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 oujhg. 0;ffogj ;+;36 rmgubkpf linked genes?

  The diagram shows a iqhvayj 4 vo(r/;tx( p5wk4 (vkaryogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosom4tx;v/(qhk vwyroj a p54(( vies?

  Mendel observed that there are,6 :8imev tmu9o.heps two 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 1:1. What were the genotypes of tp,mes .tuv9o 68: mehihe parents?

  The graph shows the frequency of birth weight of children bo0bb.awd9 r1au ar re*+j5yiv *c.5qpwrn in London in 1991.db i .* ac5pvyj 59b0awu+ q.*rarwr1e

  Which of these traits 6llc-lp v bfmc.*b*(a is an example of continuous variation?

  Which row correctly describes diploid and haploid cells ivs4o57-lt itjg0t2k. ayrbx )n humans?

  The following table shows t0 loeou4ts; (the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive ady668h;h 5mvgfg:f0hpu vg;6 a .erl lllele (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 chi ;htggqb 8y;9yld with blood type O. What are the possible genotypes of the b; 9qyg;g8 tbhyiological father?

  Which row shows the correct annotation of the w*yfhwva3ioqq/ou52.:qp5 n alleles for blood groups?

  Which of these statements are true for xdofxz, :tpkvtj0vb 19 d y;3*iw c).balleles?
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 6gdic8/ f6jb/a6 jt vna7b c7mr -ea 8c(;xmpkand the spread of malaria across the contbam mk p6ef/jvr/j7 -a; bxn686igcd(8 t cca7inent 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 by a numbenk zkuy7f8k;sq n*q/: r of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) ifyqn*k8q nz:/u ;skk7 s 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 unli cap3jr s0ri4+f60 6 kejeyt6ynked genes.

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

Sickle cell anaemia is caused by thesvkx83c1w 1to 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 showspt x* fi06pf6)b2 fqvh a cross between a male cat that is homozygous for brown, long hair and ff6qp ipx 0) 6vf2bh*ta female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shapeu8jk0 .jovwn ;d seeds (D) isuw8 ok;.jv nj0 dominant over 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 to short hair (l gz d .b)ovmxgi/cx v61fv 5cq9.):vkk), 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 gui.zc kvxf.ig1) g/vmvbox9 vk5d):6 cqnea 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 show ,i0*lhm s5tumn in the pedigree chart belit*usl m,50 mhow?

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

  Which of these statements about genetic disorders is/are correca/u/c / icbg2et?

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 nod7x a/s5k-d,me ys :xarmal 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 pedivihre6wi( 1,rgree chart is X-linked recessive and not autosomal recessiverh1rwe,vi 6i (?

  Different species of livingt,m 1w9r d9mt7l c8smg;kx,sl organisms have different numbers of genes characteristic to them. The table shows the estimated number of genes for five speci7cwlt9 ,xg 1 kl;98mmrdmsts, es.
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 pla +wdgz:*04 ir8 sdzmbqnts, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian ge 8griq d 0mbz+4d*z:swnetics, which of these statements was correct?

  A biological male with hemophilia and a biofj(yk72 qlp,wng /4r) wgbol *5vqio4 4e9ycological female without hemophilia have a daughter without hemophilia. What are the possible genotypes of the dwgo )gi(r2ye4y 5kqoqlojb *49/ c7nlw,f p 4vaughter?

  A dihybrid cross was carried out between two sunxtr6 vfdw*li 6 6f6o+nflower 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 f fn 6xt66+6wlrid*ovthe chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blo1mfn(kg/ ,+emd *k zlsod type A and blood type B can have a child with bloodf* m+/e nmzdsk( 1,lgk type O.

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

3.Explain the role of inheritance in genetic diseases.