A man and a woman have a daughter and a son. Their daughter has nors ezf9hr2a6n9mal vision, but theih9rfa z6s29n er son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somaz0o ilnve8 -3xwuf0)qtic cell in a human male?

  There are two alleles for flob xakbu.)/.ivwer colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observe.x bv i/.b)kaud phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to thef1w x eq 40s/skz6jnmx4n ,w/r correct definition?

  Which of these statements is a correct definit j2ng .augehfeei7y)0xd9. m2 ion for a gene?

  The diagram shows a pair of homologous chromostxm2eip1f eec m.n,j8j aw-2* omes.

How many loci are shown?

  Two individuals, heterozygous for a specificjlaln0: 2hf9 y0x2r dh,z hof9 trait, were crossed in an experiment. Which row shows the exn:h2hl,x hlfy920zjfr0ado 9pected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individu6d b,t cax9f-o43 efdeal hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are het3tfd, 4dae- eb9ocx 6ferozygous 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 i f-p.jd18w :9z.egm. qy)s r3 rjdj-/ned cypkn individual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seef jm1eg)kreddjydq. wj8/p c. . zn--:9rp3syds 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 chromosomes. How6tn /i ,sf;kk zpk1o:m many chromosomes are in a fertilised oocyte of a z1fpit,kks/n:6 ok;mfruit fly?

  When does the random orientation w1n 4wfwr+ / 8zs 2l/rbt2secgof homologous chromosome pairs occur?

The majority of the genes in the human genome have alreadyll3fjv r*.a 9dp-8uhi been mapped, meaning thv.h-al rp 3u dijf*l98e exact locations 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 definit:;98rrwi sh)8 kmkuwuion of linked genes?

  The diagram shows a kavdr n5kgs((6,h085j zzjc qg vryogram of a brown male rat (Rattus norvegicus). Which arrow is pointing to a pqkv 6vzr(g0,5c5jz h8 gds n(jair of autosomes?

  Mendel observed that there are two possible varj n3guv,y(hm pznp94bd1 n:i 8iations of flower colour in pea p1n8 ,p: n4m9 hyb(ndip3uzj gvlants, purple 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 frequenws6wbqwzim gmyo ,j/ c0(44( ncy of birth weight of children born in London in 1991is, c(mgqn/z4w jbyw6m4o0 (w.

  Which of these traits is an ero1r+:k-lqg bxample of continuous variation?

  Which row correctly describe4pcfjq k-77ip s diploid and haploid cells in humans?

  The following table shows the diploid chromosome numbe g1nsuqlg2qfwwm.6x w 8,43fmr of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessiv-./et( 5tp9fse um lsve 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 child with blw ioi*d/ lk :z,d7gwm,ood type O. What are the possible genotypes of the biological father? ,i: d*,klz/odiw w g7m

  Which row shows the correct annotation of the allel pwj 42lf.ddd6es for blood groups?

  Which of these statements are true for alle( cd 4bq mzofcjt-5buf80o:* vles?
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 s+ws ihzimu:3)bku 6 tzq29i6 qickle cell anaemia and the spread of malaria across the conuihzq6k9:+w m2si6 )itzuqb 3tinent 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 4l-ynpf 9cr (knumber of genes. Brown colour (B) is dominant to sandy colour 9ncl-p( ryf4k(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 unlimo.hyry4-j zu7.cp+*i .oh;wq -peym1-s gtlnked genes.

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

Sickle cell anaemia is caused ,/ e bnwxgo e;y:b8(gteiv4 s(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 r mb*w7s 1znw f9gzr+5between a male cat that is homozygous for brown, long hair and wrz9 rz 75+fs1n*mbgwa female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamondg)+u : 0i8ownf2ah (gco5atmw-shaped seeds (D) is dominant over 0)cgt+owwiug: aohf5 ( 28mnaoval-shaped seeds (d) and the allele 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 porcenb2h:) b; c,glnl/ wqkllus), 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-sglh/c;:nb2)q,klwb nquared 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 the x m 9ntz15*e*h dno8yoj hf;v,pedigree chart ;et 51z ,8n om*jhd o9fyhv*xnbelow?

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

  Which of these statements about ge03. s,/ qgt7c6g:ho-g fmgcsh ifc*wpnetic 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 dis7u/u52pbo rmplj3d bb m::p tz* fo6+stribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  What suggests that the inheritance o m;f+znge:+csr 9r oa0f the disorder shown in the pedigree chart is X-linked recessive and not autosomal recessioazn+: em9 rgc;+f sr0ve?

  Different species of living organisms have different numbers of hxbo( a*91hnhgenes characteristic to them. The table shows the estimated number of genes for five species. 9hnx a(hob1h*
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, inc8 lb+qq ;vr p*tv h5r4o-gbi1pluding flower colour. If the pea plants Mendel was studying can only be white or purple and follow the ruleiq+ pbgrpob4v 581lvr-q t; h*s of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hel(9yhqb ) sy,lih cv9.-yrk5cmophilia have a daughter without hemophilia. What are the possible gen 9,hyvl h.cyqs y(9-rc5b)kli otypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annueq lzvhg03.v- e9)lhbus) 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 veh3-lqelzhb0.g 9v)for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A and blood type n3; nvbs.gpc2kv0s91t )srl zB can have a child with bloodn b1vsg2csslk.03 n z9pr;)tv type O.

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

3.Explain the role of inheritance in genetic diseases.