A man and a woman have a daughter i0r(+ z/:i8fw9fii8vpjhkx uand a son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the bwijk/i f u 9x0ii+8vp( r:z8fhiological mother?

  Which diagram shows the sex chromosomes of a somatic cell ignbaryg ve;o 3 p1v6p4s 85jc4ju c5x2n a human male?

  There are two alleles for flower colour in snwmk 0amdz1c92 apdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white 92m 0dm azckw1and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to t5 - ijy.bikhx,9df;j vhe correct definition?

  Which of these statements is a cores rr(9f *:kfbrect definition for a gene?

  The diagram shows a pa4e3ina vo,+t/gp v4 sair of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were ciyw0r;hq65n2 svw/vn rossed in an experiment. Which row shows the expected phenotypic ratios of the of2; nh/ 60w 5yvivnqwsrfspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to hjbxdh0r5n )1 iave a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygoubd1 x0 ij)nr5hs 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 wahf+j 1j v6z )qf9:ght7rjod*bs either round or wrinkled. The results of an experimental cross yielded 315 offspring with r:jz q1fh7d+tvh6 j9oj*rf )bgound 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 chro4rq:w..vq v lrmosomes. How many chromosomes are in a fert:q vwq.r4lr. vilised oocyte of a fruit fly?

  When does the random orientation of homolo2oq-jf1+t qt pgous chromosome pairs occur?

The majority of the genes in the human genome have already bm//fu k ( qkt0t)a9qkaeen mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pamu kk(0q)/t9 ta fk/qair 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 genesc)pu-bzsu , dnf;,9od?

  The diagram shows a karyogram of a brown madd,2q2;m aa, +xukdkfle rat (Rattus norvegicus). Which arrow is pointing to d aqx2+k2,dfm ,au; kda pair of autosomes?

  Mendel observed that there are two possible variations kldaw0g/2 tto*w 67gqof flower colour in pea plants, purple and white. After a genetidoa 2 60wttg /wg7*kqlc cross, the ratio 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 of chif)mvf; ma mp.tx-xk:,me(ve-ldren born in London in 1991fm: -- v;(aem)mf e x.mk,pxvt.

  Which of these traits is an example2un9h rf bkd+xa*1 q4dtf9 y/t of continuous variation?

  Which row correctly describes diploid and haploid cells in humans? mo(c od75qx(,bno9 w+ 2zd +xmx)mbru

  The following table shows the diploid chromosome number of a range of udqz1 t2r53sz:)v hiz7vi,vxspecies.

Which of these statements is correct?

  Sickle cell anaemia is 2 qt+bvip0z. uv mrz:+caused 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 ch-vrgrj,p 2o y0ild with blood type O. What are the posrypj0 gv r2-,osible genotypes of the biological father?

  Which row shows the correct annotation ofiarv6c *d:c7 7j2 q3zftp vp n2rhr0k6 the alleles for blood groups?

  Which of these statements are true for alleles? (r bwm5 58vzfl
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 ofyi e*3(qsz7p l6bl7+sq6scmofzp(l/0n xl p/ malaria across thepf/bqlep c7((iy/ 3 l6qzlso+xn 0ssm*zl76p 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 ca2py7*03hwd kcxpg- przewalskii), fur colour is determined by a number of genes. Brown colour (B) is dominant c2p0 -pk x3cwdg*hya 7to 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 vius1pfqpn -v;afl 9a*-y u4/ linked and unlinked genes.

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

Sickle cell anaemia is caused by the allele etga4 6;z 9oheHb$^S$ . 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 mal68ypkj9p1rz ee cat that is homozygous for brown, long hair and a female cat that has black, s ejzpy16p9rk 8hort hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), ttv(h7(o .ed dwhe allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the at7h(vdw ( ode.llele 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 doa2ce3m0 u0wbb minant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male hb buc m03ewa20eterozygous 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 i ozad,7wexbxk+p;)+* kexm u* nheritance of the condition shown in the pedigree chart below? a; x*kw+e x *u,p+kz xdbeo)m7

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

  Which of these statements about genetic disorders y)(zf /t.j9zuw2hf)d.vc z keis/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 traitsq(ma;yq v1bpwbyp6zm7 06sc)s7 y mtr:q(y; r can show 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 in90mbv(30pya*k h xr*)h j tidqheritance of the disorder shown in the pedigree chart is X-linked recessive and not autos pbxd*j90r0v3hqa k*himt(y) omal recessive?

  Different species of lmd ;w)0o10wc1n ks 4seadu;qkiving organisms have different numbers of genes characteristic to them. The table shows th0k1keqsd)o ;ucd4;m s 1wn0awe 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 charac2)4u;hh xdka ldt,wg/:5os mwq2z7b rteristics of pea plants, including flower colour. If the pea plants Mendel was stu;dodrms4)zhaw2k tg 2 l bqw/,h5xu7:dying can only be white or purple and follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophilis3jkc8 1npw 4pwxbr7m p0 s:o3a have a daughter without hemophilia. What are the possible genotypes of the daub 8s1w4c3px p 073: pomjswrnkghter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus il:sh63wvy .bv qfdd49s0( irannuus) to see if the gl0sdr6d3fq:iyv(s4h i v. 9wbenes 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 type A and blood type B can have61i9hq apcm, u a child with blooha,1q pu6 c9mid type O.

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

3.Explain the role of inheritance in genetic diseases.