A man and a woman have a daughter and a son. Their d1cl nvt7lt25q2 ughvo;- 8c pxaughter has normal vision, but their son is colourblind. Which one of these genottq7-x8;2 l tvvhnc2cp5uolg1ypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a saz;j 9 3ko r./vg l3likwih24domatic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, uzmgr:ye 04; ethe result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which m :egz0 re4uy;is the most likely explanation for this observation?

  Which keyword is matched to the correct definuwq1+ 2:w dyjdition?

  Which of these statements is a correct definition for a grrvv-3 1osgu.to ( y:hene?

  The diagram shows a pair of h33d z bt jz3n9/jlq9cromologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, ye k6 4ccj8cxopft 1/zai5.n3xy:o,swere crossed in an experiment. Which row shows the expected phenotypic ratioy f, 5nz oik8asp/c34xoc. etyj:1cx6s of the offspring resulting from this cross?

  In some animals, the agoucy 7q *h()gmdrti allele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to*7r ydgq)m(ch 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 pbki+we2u0.za afwloql5 u fq /3 4as/rhrl3(+lants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled (ur4u+3 hkel r3.q ifw/2 0w/q baol5a+fs lzaseeds.

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

  Neurons of the fruit fly (Drosophila melanogaster) have 8 chromosomes38c 74la krlghzr/s3t. How many chromosomes are in a fertili83 hlkg7cszar l r34/tsed oocyte of a fruit fly?

  When does the random orientation of homologous chromy l104zm ngaw-osome pairs occur?

The majority of the genes in the human genome have already been mapped8 + bbumc.x9pb, meaning the exact locations of the genes on chromos9+b.8bupbxm comes 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 definition of linked3- 5 b;disl:ewtm+lsqd r)k7r genes?

  The diagram shows a -;8 xyjrdfbd/d ygy58karyogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pair of autosomer;y8j8gd b/y5 x-fdy ds?

  Mendel observed that there5zf wu-pjd*nnk pb) .7 are two possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to whid7 wbznk*pn.jpf- 5)ute flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequensn32wy52 8:ntptjv 0idk ftuj:juvr,v 07v 8mcy of birth weight of children born in London in 1991.n, m3 v70 v8jr y80fkvjwt juviud2tt5n: p:s2

  Which of these traits is an example of continuous variat6 d kml ab5w4bc(1ww6uion?

  Which row correctly describes diploid and haploid cells in v23g3dd22a dqc6 lzoehumans?

  The following table shows wsd+,nij-w:h nra07g the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is causedjxy9)kv, ap. m 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 27cpkwf n)g2u - vs9 oaye(3uvchild with blood type O. What are the possible genotypes of ty 9kc g(fsu)nova2e3wuv- p27 he biological father?

  Which row shows the correct annotation of the alleles for bl -r3qmqg),fa36 s zpmiood groups?

  Which of these statements are true fo-+;k( oo7zyezmy kh :xr 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 incil5snsa s48 .uxpzq rg.m; l95k/qweh:dence of sickle cell anaemia and the spread of malaria acrozqmkr 4xqh/s5n5;8g 9w.lesa .ups:lss the continent 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 number ofatr r 8/y80xjgu7crz8 genes. Brown ctr /gry8a8rju07 x8cz olour (B) is dominant to sandy 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 genv(9i,7ax r7dn9n gpbc ld 0hl:es.

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

Sickle cell anaemia is8j50 av0d .x l9akiy +a8sddlahj,3sv 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 sh rgyh4gy3z fkuw2b2/) ows a cross between a male cat that is homozygous for brown, long hair and a female cat tgr/u)z k23ghwfy2by4 hat has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped seeds lxd: x42fj)84 fm uoxn(D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant ojd)xo 82nu x mfxfl:44ver 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 pia0 v4t9njs.8zvq2c;e r s(q:e olu a8orcellus), long hair (L) is dominant to short hair (l), and curly hair (C) is djee4(0 z i;.8 n2soqsvtvuaa:8rlcq9 ominant 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 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 1kezq(b3k k+*dyyhn) in the pedigree chart d1y k hekqnb) *3(z+ykbelow?

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

  Which of these statements about gene fxdxbv*m jg2l 3df n1c-5v67etic 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 a normal distrien,e-y 0osw,f bution.

2.Outline the differences and similarities between homologous chromosomes.

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

  What suggests that the2n 7jg*xpfwv(cf8my8:vsq c; inheritance of the disorder shown in the pedigree chart is X-linked recesf8*s8fnq( vm p: gc7jwy;xc v2sive and not autosomal recessive?

  Different species of living organisms have different numbers of genes charac85fy :*3 flg4xproszm teristic to t5s4 xzfrf8og y*ml: p3hem. 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 peavnx: a,y.f/cq.tz;ys plants, including 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 statements was co tyf: y,/qa.;x.zvcsnrrect?

  A biological male wity lq( rg:hidig o7dt(p7um8+ )h hemophilia and a biological female without hemophilia have a daughter without hemophilia. What are the possible it 7l(yr q: 7g+(imdh)8udgopgenotypes of the daughter?

  A dihybrid cross was carried out betweenn5 hv,bq:mq/ k 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 calcula bqnm5: ,k/hvqted value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood ttwpc5e6l- o bze 0v1x7hnm-+ qype A and blood type B can have a child with b+ e6c51 e-b0p7lqnzmt hv-o wxlood type O.

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

3.Explain the role of inheritance in genetic diseases.