A man and a woman have a daughter and a son.p-5m 4 eat( ns zlr4+bgn(eod. Their daughter has normal vision, but the-np e(e5slgn4b4 rtz adom+(.ir son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cm0 r9rua56lfno m/b7y ell in a human male?

  There are two alleles for flower colour in snapdragons. However, the result ofwlmdk l4be6 zdr3wlsg)a9 968 a cross bed k96brl6 wl m9e4adl)g z3w8stween two heterozygous 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 mat1y j6pe2df5bd7fd :zdiv./e+ bm6kz(t p jf .vched to the correct definition?

  Which of these statements is a 8ap7 ;vg:jyp;ach6 fd correct definition for a gene?

  The diagram shows a pairh+:m5bs)pr8w; namz x of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, werq5ysm*uoqbt6:, 7q v9v tkl0we crossed in an experiment.5 l0voqqkwq s6 ,*vbuy9m:t7t Which row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to ha/s /fg-7h a,(pvranyhve a banded pattern. nf h/gv,hrpay- a /7(sThe non-agouti allele causes hairs to 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 sha .qyx-fihu*8+vs/nvph,kg1 )+k tw nape in individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and i/ tqvwfa1gxn++u hv yp,k h8n.-*s )k105 offspring with wrinkled seeds.

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

  Neurons of the fruit fly (Drosophila mleqqgkoo ) ,yc0 u*/wlf8n9hlwy4y0 5elanogaster) have 8 chromosomes. How many chromosomeghq9)wqcl48 o,k uly fwn5y0/o l*ey 0s are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome pairs octmg1, pd+hnac,c s 1+ecur?

The majority of the genes in the human genome have already bee6 lrs: vaqu,x;n mapped, meaning the exact l,av;:q x6lrsu ocations of the genes on chromosomes 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 linked geneoc.iq8d j9 ltlyt1g);s?

  The diagram shows a karyog;nn+z,/. cmr d +zt,x dobyjz+ram of a brown male rat (Rattus norvegicus). Which arrow is pointing tbdx ,,t.nyz++ r;z /odnzm+cjo a pair of autosomes?

  Mendel observed that there ax1x 29ms 3tw sokl+,famfam(4re two possible variations of flower colour in pea plants, purp3 kl9 s21ma(xxfs+wo,ma mf4tle and white. After a genetic 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 weighh9bx 4of0ayl(qxu u-a4gxj,7t of children born in London in 1991.4(fb0axqu9lg hx7 , xa4jyo-u

  Which of these traits is an example of continuousj-ly-l qqciav6); l-j variation?

  Which row correctly describe,b 48qsurim )i9y qla*s diploid and haploid cells in humans?

  The following table sf (hq+m fr:h*xhows the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive1 9a+brx(lu re 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 typxe94 qsu:q.xy e A had a child with blood type O. What are the possible genotypes of the biologica. yu4e:xs9xqql father?

  Which row shows the correct annotation of the alleles for blo*2sj0x+lf3z3 w ffperozr 0l +od groups?

  Which of these statements a2p*omze; dlk *8t5mm ire 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 qt)p1e)v)oxif 55 nyq of malaria across the conti5nq)1v5 ) iqyxo) ptfenent 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), fu )zaz;j +/oaxmr colour is determined by a number of gjz+xaa/o;mz ) enes. Brown colour (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:c y 6mrn)eibh*::kwhhle20 f genes.

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

Sickle cell anaemia is caused bi9gj- pciz 3nhf h:g +d90cz7its9)u vy 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 cr,c wel:*h jd8 u-r bhk3p9upp:g.tk6 poss between a male cat that is homozygous for brown, long hair and a female cat that has black, .rlt6p 3h-pgc:edupu pkw8,k :*9hj bshort hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinhw,/utr qo,fc b6se; 5ale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele hwf /u c,t5,;bo ser6qfor 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 (L4.s;ebgvsua ) e0v9mzn ch s8:) 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, stra umbcs) g evh94na.;vse80zs:ight-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 oiy2o bue z h9di88( )mgz+c41hi-a hushown in the pedigree chart bei (m2ucda9o u-eh48+y)izz hb8i1gholow?

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

  Which of these statements a 4*vht1vi6aqv:gi 9qszembu o5akl7+s--k5 about 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 a normal distribuqz; /3adq af 1-aakt )+6cbtgetion.

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 pedigra+w0*) sz ahuyee chart is X-linked recessive and not a*w uazy)hsa+0utosomal recessive?

  Different species of liviqc i,rh 7pf6rfvk :t/csvse0ts8js-3 osp .++ng organisms have different numbers of genes characteristic to them. Ther-jrqfie8. v /s sh tkv7pt,fo+spsc sc03+ 6: 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 pea plants, including flower colg2q0 /af; svax1 o/qisour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian1/aq0 a /ss;xqo2 vifg genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hemophils hj0)98j0oct x(s(b6qcx1xrnu1 ,rij a n8z fia have a daughter without hemophilia. What are the possible genotypesxor1r n ji9qs0fj xxhnzs(01,c b8(auj)c6t 8 of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthusz+8g mzt0st :4x,ijca 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.s0xt mt+zjgi: ,z84ac The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents 7-) po npkq fkioo*0 l9e8kj8dwith blood type A and blood type B can have a child with blood typ0 pkoq7ld oen kj-8i9 f*p8ko)e O.

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

3.Explain the role of inheritance in genetic diseases.