A man and a woman have a daughter and a son. Their daughter has norn e(j7c)kx,ls mal vision, but their son is colourblind. Whichx ejs,lc7nk() one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somaticm,4hiu fhzoa-rls6m n))r 27 o cell in a human male?

  There are two alleles fd(6c l: sbni7b*ac *juor flower colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Whj *u( bc6dclsai*n:b 7ich is the most likely explanation for this observation?

  Which keyword is matched to the correct definitxclt56nc*fja ;izb857 b( b ytion?

  Which of these statementsw1z 5 iy00,2yksmlniqvmj6k 5 is a correct definition for a gene?

  The diagram shows a pair of uraxg :vr)73u homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in 5g 4bk *hcg)yda9)t5cdym8 eran experiment. Which row shows the expected phenotypic ratios of the offspring redg5cct) 95y y)b rmg4ad8keh*sulting from this cross?

  In some animals, the agouti allele causes indi)z7bgx *w1ub5w a :x.)fcpty2oyp5je vidual hairs to have a banded pattern. The non-agouti a1 7pey2)j.bcxu*tf )o 5p5 xyw:zwbga llele 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 shape in individual pea no 2zx: 3i*wx0pojk4hplants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring*oz3k p2nioh0:xwx j4 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. How maji -6cqic9qq f0w4qb/y.p je eo,wu:)ny chromosomes are in a fertiliyj uqe/jpq )6wwo q0-i .9cq i4bc,:fesed oocyte of a fruit fly?

  When does the randome8 eflath-5gi;. m ic* orientation of homologous chromosome pairs occur?

The majority of the genes in the huybp2qmd63dz / qfy64nman genome have already been mapped, meaning the exact locations of yn4qf/qyd 3d2 z6b m6pthe 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 definitionwt:)s -nas8( dddyes - of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Whi2 u gaukavn*6j+ .,r dgmue+3ich arrow is pojgv6ug i+rm* +2n .e 3u,kaudainting to a pair of autosomes?

  Mendel observed that there are two possible variations of flower enl. h9 0gugw:(z:tmycolour in pea plants, purple and white. After a genetic crossl0ymt9enz w g::.(hgu, the ratio of plants with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequnc i.8nuv wy38x+ vcy0p9+pfmency of birth weight of children born in London in 1991ic.8n +pu0 y wv9y m8v3+pxfcn.

  Which of these traits is an example of cont5.trlfcxz,ywo(* 6k)vfgn 4zinuous variation?

  Which row correctly describes dip6hmzou- n1 8fbloid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of specidg(g iqn3d-j* es.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allel/njo:o cqr4e/iw 5xgmp0. a 9ye (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 blood0ai/aoccav9-(s j-(z qftfm5 type O. What are the possible genotypes of the bioa5 s/z ( ao fat0-c9f-jvicm(qlogical father?

  Which row shows the correct annotation of the alleles for blood g2 62xk*.z t0qxyzlm 0xp c3ujwroups?

  Which of these statementsjg.cd;wid- p/qbqnx02 +ng e/hm)y ((a;qipm are 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 of malaria acxgn0:olg i8t5r a8 ae0,qk, dd/,zv ffross the con,f0v8i rfzgelxo d,,t5 na:qad0/8g ktinent 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), -.d2v6-cnxxyfv m l/ 7it(wpwqz o46j fur colour is determined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (t.mc xx w7q2z6v-i6/ovtnpjly- (f d w4wo 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 an bs55):lyst gtd unlinked genes.

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

Sickle cell anaemia is caused by cwbm;fxl,eqy u.uzje0p ;93o8 .wh- tthe 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 croh3z-r* p o7gbbss between a male cat that is homozygous for brown, long*hz-g7o3 rbbp hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the al/)b )z3fbc2* f0tbqusruq2v vlele for diamond-shaped seeds (D) is dominant over u)f cb/qs u r2b 30)tbvfvq*z2oval-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 (Cavipxmvcu - voy-g42w3r y djv;+t*6+wzy a porcellus), 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 pipc ygxu z+wd mw36vyy4v; 2+j-*-ortvgs 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 ecc9qq7 /ntbd0z vzcj,k,7w 2inheritance of the condition shown in the pedigree chart below? wnj ,v072ctdb z/,7kc9 qq cez

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

  Which of these statements about genetic disorders is8x u omt+8,h3vdy1hjlgp 4-df /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 polygenw,u7e okonn;tc3lym ph;j;-8o4 .t ehic traits 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 inheritance of the disorder shown in the pedigree ch8ebe-*oj* i orart is X-linked recessive and not autosomal re*eo-b i*or8ejcessive?

  Different species of living organisms have different numbers of genes charkk*;qj9 e ye ,l4z9,c)ghqq * ktbn+auacteristic to them. The table shows the es,*b *,+9 e4hkznlqkqg jeq y9) uakc;ttimated 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 plant7ydcpqj3y.wbk, 2 4xsz1 ,(txxlfm- gs, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow t7 ,3.4yt-l2myjf(sbzp1 d w c, xxqgxkhe rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophvsbh-sq zp4 +/ ogl*ofqc:)s2ilia and a biological female without hemophilia have ac2h/svs b -q*o)l 4 p:zfos+qg daughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out betweeni iu(6*. uphyj,qe(ju 4/oue b p(i.ru 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 wa6u(yp i,.jp (ib eo.u(r u/u qheiju*4s 7.82. The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood6i+ v3tls xu7r8rfuuu7x,sj8 type A and blood type B can have a child with blood type O. s3u 7v,i6fxtr8s7+rlux uu8j

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

3.Explain the role of inheritance in genetic diseases.