A man and a woman have a daughter and a son. Their daughter has npz*s5o h fi+f3 *u upj)axs30eormal vision, but their son is colourblind. Which one of these genotypes could be correct for the biological mpuf3*j 0s+xs p)z5a fe*i3huoother?

  Which diagram shows thevp-my2i . zgcr,p ,0gy sex chromosomes of a somatic cell in a human male?

  There are two alleles for flower colour in sn 9o0h1wmhng- xvat/ 1fapdragons. However, the result of a cross between two heterozygous plants ytf/19 0mgo x1avhnwh- ielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct du/os 7b(cvk1hefinition?

  Which of these statements is a4p ghan0b5r( o correct definition for a gene?

  The diagram shows a pair of homolog72g pmins h+p)m*q:b k a7k0gpous chromosomes.

How many loci are shown?

  Two individuals, heterozygol5h b 3x:j hst3obof-*1cz;qbus for a specific trait, were crossed in an experiment. Which row shows the expected phenotypic:fhq 3b3- obx zcot1j;bls5*h ratios of the offspring resulting from this cross?

  In some animals, the agouti allbg12jk/(x t:p9y (ysuf f6chgele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour.x(ft9b :gy6 f1( s 2hgjcy/kup 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 plants was eithepu b1wu3d.yt1r round or wrinkled. The results3u1.w udpbt1y 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 fruitr8vrr-i*qhk.u0q+ j,cz x z(w fly (Drosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fruiw jzr8ci*x.k r(h0v r+-,quqzt fly?

  When does the random orki u*f/ gqy4m.ientation of homologous chromosome pairs occur?

The majority of the genes in the human genome have already been ma1 a b2:5jcd++nnxyjd: ngnu7qpped, meaning the exact locations of the genes on chromosomes are known. Thjg+ n2nx: nd5abj q1+ucy:d7 ne 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 gene* w+d dinl(ro28jlay4s?

  The diagram shows a karyogram of a brown u04 o 6uqv5 (h i:ca:gpp* (nbhgppww6male rat (Rattus norvegicus). Which arrow is :cqh(i4: gp66og w v*n0auhbpp pu5(wpointing to a pair of autosomes?

  Mendel observed that there are two possible variations of flower colour in pt,m)xh3 t +w.jpp*v- td:tmptea plants, purple and whpmh w ),vtt*-. ttdjm +p:xt3pite. 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 weight of children born in London in 199+pdg e9fy*(vk 1pf g(*9ek+dv y.

  Which of these traits is an example of tsr..y-wrn ei5 2brgsj:b w42g hh,6ncontinuous variation?

  Which row correctly describes diploid mi9i9dx iib + vkh.5.qr :mvh-and haploid cells in humans?

  The following table shows the diploid chromosome number of a rtf,tb1- yupv 2,m:*a: jyu lhyange of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive )0e-r ez tdhf.)+pkucmy/)c uallele (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 typqo; 7go noqv;.e A had a child with blood type O. What are the poss; o7gq .qvnoo;ible genotypes of the biological father?

  Which row shows the correct annotation of the alleles fccmrm)td4 0 x2or blood groups?

  Which of these statements are 7 n-+kn i)a94suu,nfc7acc dotrue 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 of:l; sr1s,fkvedxe;z 8 malaria across the continent of Africa.sk 1:v;8xfdr e;, eszl


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 (b:k2mv)hhhh , v jo.k;;zf xl(Equus przewalskii), fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to one thh;k hk2ov), :;lv m(jzb.xhfone (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 betweezb0hsp:l80g2h( qc z4z qoho/n linked and unlinked genes.

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

Sickle cell anaemia is caused by then--5i./ry.bqr prah m1jp ujhh 6wn 42q,uk/l 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 shov0e:t,(ge pva. ly *wzws a cross between a male cat that is homozygous for brown, lon:vave0gpy w*l( ,e.tzg hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale um8d:w;jpua .k0gvd,), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) ipuku .j da80w;vdmg :,s 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 h74 x3 uyls8ndtair (l), and curly hair (C) is doyx4s3nltu87 dminant 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 in sj ajev,e5w:9j f*kz- the pedigree chart below?wsv jz5,je- ak9fj:e*

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

  Which of these statements about genetic disorders is/nao frb4wo *14s:ar gbr3 2(y2zmwe;0/ hzbhbare 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 22n t7r4-bjioke i;mffom7d ,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 inheritance of the disorder shown in the pedgs +jwron4iri qm4 d,4f* *1 gp7nrbu5igree chart is Xpf7dr**4g51m rnnb4s ,uigqiro+jw 4-linked recessive and not autosomal recessive?

  Different species of living organisms have different oea eq6z+6fhfut , lm ,twl982/sdc;inumbers of genes characteristic to them. The table shows the estimated number of geneeh;8ft,lqe 9sd6u i/a+ 2ofzwlc ,6 mts 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 8l 4kldl /) qekckx527hhb1j4wb9gsvplants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow thebl jh4 k/52b48 h7vqg9kllkwxc1e) ds rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemoph be pxz08rb ud kb)kqz:vd+4s gt+*c 30jtfc./ilia and a biological female without hemophilia have a daughter without hemophilia. What are the possqkvt84: zd sekfbuz*x j/0 +c3pc. btg)0rd b+ible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (H+opg4 *pwl+mrd , n3ymelianthus 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 calculated value for the chi-w* oldp,++g prn4m 3mysquared test was 10.05; what does this indicate?

1.Explain how parents with blood typer6va99 y3tqok A and blood type B can have a child with blood qo6 tkavry939type O.

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

3.Explain the role of inheritance in genetic diseases.