A man and a woman have a daughter and a son. Their daughter has norzmv9pyl + k u74kgs64kmal vision, but zk pkvu6kg49+7 mls4 ytheir son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic ck9s;-ep hk027m3nmuao*ho-d i k*jo cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the res edkvp*t0( rud;k r7iwy,/; znult 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 this obse7; *k0rir/z(;ypvt dw,dekun rvation?

  Which keyword is matched z qx+mpb5p77 j2l( aulto the correct definition?

  Which of these statements is a correcg np2n 5 (;(etr3axybzvyl /6ft definition for a gene?

  The diagram shows a pair of homologous chromosomes. :*biso/td d6v

How many loci are shown?

  Two individuals, heterozygous for a specific.r 6vu,rp5 vni trait, were crossed in an experiment. Which row 6v ru .p5,nrivshows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allewpp+*c j9 ,chole causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous hac+c * j9whpop,ve 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 plantc fknazco)wp:u 21o 4oq di./7b-r(wf s was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105k)u qn7- ci(c.2 1/abo wodrfwfz4po: offspring with wrinkled seeds.

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

  Neurons of the fruit fly (Drosophila oqo4i 8q s(w 5t9jse7u(x*tt xmelanogaster) have 8 chromosomes. How many chewxxss o*ttq7o5j((u8t49q i romosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosomfa/7: k9 w+5jbj 3tzt4gs bvcie pairs occur?

The majority of the genes k81ia1*2on/l9 sjz iqj avb7tin the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of sa*q1tii2vb78a9l/o zn kjj1 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 gr-r e-9jhiie*cuc a62enes?

  The diagram shows a karyogram of a brown w6ao2zwa)c-gs)d d wmd4:p:c male rat (Rattus norvegicus). Which arrow is pointing dw6) cwm ap-o dwc s4d:)gz2a:to a pair of autosomes?

  Mendel observed that there are two possible variations of flower colu67*d.vj r /giar r7d2t+ivr mour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:12 ad.mr+/dr rju*6g vv tii77r. What were the genotypes of the parents?

  The graph shows the frequency of birtg75f3 /yzx2 lnzcu8cth weight of children born in London in 1991/t3yl x cz52uf7n gzc8.

  Which of these traits is an examp b wp.qbgy (ia-h45vt2le of continuous variation?

  Which row correctly describes diploid and haa7jraxvi j-)5 ploid cells in humans?

  The following table shows the diploid chromosome number of a r z 9a,va2qzp*vange of species.

Which of these statements is correct?

  Sickle cell anaemia is caused bwj+dkr,r9oo: y 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 childtsc 8 os:, s(l5 hi,ry*.trrqulon+d , with blood type O. What are the possible genotypes of the biologic u h(tnll,oorsi+, ctq:syr 8d*.rs5,al father?

  Which row shows the correct annotation of the alleles b ,jf3 nt0sq8r9g, rerfor blood groups?

  Which of these statemenmii6.vhiyv0 bh:1zsi , 6k37gbz u( hgts 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 spread o .oof an;,vbhn8;6 mlhf malaria across the continent ovob8hfnom; 6 h;ln.a,f 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 -u:on-u 1hip bdau4n0a number of genes. Brown colour (B) is dominant to s :-hdaun p-4ouui0 1nbandy colour (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 unlinked ge3ost09 mquywjz4o16eti/sbg2/j1 r znes.

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

Sickle cell anaemia is :u9j3dxpu a 0ac*ho4//rspjl 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 between a male cat that is h* 7hsxqr so.5g) nl:m*obc n:domozygous for brown, long hair and a female cat that has black, short hairlq r5) sn7:hc:xo.o*snmg*b d .


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allel4yq bx/ c1o*7t;qpwv witq( n3e for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short seeds (l). yo/pv ibqw4c1n qw*q t(73;tx

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 porcellpld:ay5ju: g2o u5 6keus), long hair (L) is dominant 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 ygu o6pjda5k5e: l 2u:(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 shown in the pedigree char+c+soan k+ e)dt ben+k+eas +dc) olow?

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

  Which of these statements ab1: g,njdce;adc/ d:s ,wk(jrqout genetic disorders 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 ae+ 8-* p*sola7xenhak (3bilbc5032p o f omfr 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 pedib:s yae)k 0 dr0diw:y6sibvo0o zh*,* +gv,g sgree chart is X-linked recessive an6yd*adysiv g*oko,wegb0::b, s0 0hv) +szrid not autosomal recessive?

  Different species of living orgztcpd b9y.srymc;y r,7/g *oqp 2k09ganisms have different numbers of genes characteristic to them. The table shows the estimated number of genes for five spec py ,p9t0 2z9o7 .grq/s;ccgy dmy*brkies.
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 c+sc lp;v/(n lscg hrmv2jm/6 je :20xyolour. If the pea plants Mendel was studying can only be white or purple a2vll;e pymh m+ jv6: r0s//c2 gxncs(jnd follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biolo4 dwy2h /n og./wx;welgical female without hemophilia have a daughter without hemophilihe /2x4ow.gd yw ;wn/la. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflowelg;,oy,hig o4 r msoiu3,79vbr plants (Helianthus annuus) to see if the iimgsh r39go;l ,7bo,y4 uvo,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 indicate?

1.Explain how parents with blood tlq33 /k3:6tbdwr+anvnm 3e x+nb78bz m*r fbo ype A and blood type B can have a child with blood type O. n baqxlrr 3+ednn3t8 3z+3 wbbm* mfv bk/6o7:

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

3.Explain the role of inheritance in genetic diseases.