A man and a woman have a daughter and a son. Their r3bxdzznh+3, l: 8j0q/sji brfb5 uc5daughter has normal vision, but their son is colourblind. Which one of these genotypes could be corrjbh bxzc533iru, 8 qzfblsn5j+r: 0/d ect for the biological mother?

  Which diagram shows the sex chromosomes of rxpn mai23.o*a somatic cell in a human male?

  There are two alleles6d mv 22xc:rgp0qs+qaotib 47 for flower colour in snapdragons. 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 explanation for thdo c0apqi4vg7 q:+s rx2bm 26tis observation?

  Which keyword is matched to the corr1ab f1r3lg /xb bg1yb;ect definition?

  Which of these statements is a correct defiu y,in/ rjy6i4*ulkx e7mgfj)yi h6,7zm( u:pnition for a gene?

  The diagram shows a pair of homologous chromosomz uuz61 zkm9np7+/cdies.

How many loci are shown?

  Two individuals, heterozygous for a specifictex.1c03sv ) e6pwwal trait, were crossed in an experiment. Which row sho 16cw vpastl0e3) wxe.ws the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes m9yfil5ca 1w 5;dqc +pz01lkeindividual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single col1lyqdplz+im;ew50k f51 ac 9cour. 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 individub jm7had4v1n* al pea plants was either round or wrinkled. v *abnj 7d1h4mThe results of an experimental 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 melanogas5nrmw*vgo/ t+ ,izt3 rter) have 8 chromosomes. How many chromosomes are in a fertvt o5*irmzrn3t , g/+wilised oocyte of a fruit fly?

  When does the random orientation of jl.d+ k:ths p9 c8jf-i7mq.nahomologous chromosome pairs occur?

The majority of the genes in the human genome have alrea854stvoa c:pxdy been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows onecap:vxtso4 85 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 of linked genesnq1z.:fs9.d t wb;2j zgstz)i?

  The diagram shows a karyogram q:3utsxwmy 4 c.6g eq(of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of . 4x :t(gmswe6y3cuqqautosomes?

  Mendel observed that there are two possible variations of flower colour in pea eq6 vv-y(s;zxplants, purple and white. After a genetic cross, the ratio of plants with purple floweyz sv -6vq;x(ers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of childre 9xi1fgqr12non born in London in 1991.f gq2rxin191 o

  Which of these traits is an example of continukh5l5dqu d5)jcal5 p/ (ad 5jsous variation?

  Which row correctly describei:utvtbs3f8t: fy 8)to0on j-s diploid and haploid cells in humans?

  The following table shows the diploid chromosome numbercjma1ee(x fg99:;q- x:tf1 ev0oxjc f of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is causedfc7+)qm 4u672odyfmk e 2 cday 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 child with blood type O. What n.w::/ whiswn73-gq idr9skmare thirm:-n. n3 gsq 7ik9h wdww/:se possible genotypes of the biological father?

  Which row shows the correct annotation offo(rydu*0+ u o the alleles for blood groups?

  Which of these statements are true for alleles7ot ni y(udh7dtc*3bpt5t/9v i- y f*y?
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 spreakd/blmw-d2i x 4c by,00 bp1nad of malaria across the continent of Afrildx,d-0b p1/ia wbkn m2b4yc0ca.


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)1 2xkqw9/tc- i/ /xpzx fva2bep.k)zvr3muy2, fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colou xw1zevypmf c- 3vu22b/t k)ak /.i9xxq2 /pzrr (b) and an ombre (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 )7+jnaw r:hvi unlinked genes.

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

Sickle cell anaemia is causedg .37 uf97gaev xqszv) 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 is homozy2 ih reqvr*:6ogous for brown, long hv o:*r6eq2 irhair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the l7oaq;84w c* fnliehz ,eo7o0allele for diamond-shaped seeds (D) is dominant over oval-aol7nwe48 7o,eol ;zq0ifhc*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 (s/2d54ytzkwix1u ia- lm5;z w3 w3kuw l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous long, curly-haired guinea pigszl4i2 w3 s ww k i5a-ud/5y1xz3u;wtkm 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 s bwhb9;kp :419ncudg of the condition shown in the pedigree chart below? g bp s91wb4nd9k ;:chu

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

  Which of these statements about genetic disordtf gh9eyt /dj/rk ec5;(,yf dyu/s :)fco9 k5wers is/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 show a :)gc eugga;9rnormal distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  What suggests that the in*) ys- -smr* lu7maxvwheritance of the disorder shown in the pedigree chart is X-linked recessive and not autosoma*lmsyusa)r *- vm -w7xl recessive?

  Different species of living organisms have dlahz8kp)t/j q2w, j(jifferent numbers of genes characteristic to them. The table shows the estimated number of genes for fi/hz), (q8j jjkaw2ptlve 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, including flower colour. Ir1un k)fo;d 5lf the pea plants Mendel was studying can only be white or purple and follow the rul1rdn5; kf )uoles of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female withon4av.qhs 1v2 uut hemophilia have a daughter wit4s2.ahnu1vq v hout hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunfns 5pel y 3wo(0 )kqzduuj0g:4lower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The crit (04q0ykouwg53sj nue l)zp:d ical 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 indicate?

1.Explain how parents with bloow sh5 hiy,+l0/ypt 1u tw0pm:md type A and blood type B can have a child with blowhm/ m:0l 1wy st pi,u5+tp0hyod type O.

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

3.Explain the role of inheritance in genetic diseases.