A man and a woman have a daughter and a son. mwmtjuaou 360gskv4 :(y(ol/Their daughter has normal vision, but their son 06ay(wku(jum3oos:vglmt /4 is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the 2ma (-v axm0mv5aujrb3.m: lcsex chromosomes of a somatic cell in a human male?

  There are two alleles for flower colou*;v+7 jrqu ljv.wbucl,6z/rhr in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explaubjvwlc*v./zqru; j,7l+hr 6 nation for this observation?

  Which keyword is matched to the correct b r ,qiu4+yux/definition?

  Which of these statements is a 8tk5snc6x,ztz7jsr3h r1(yucorrect definition for a gene?

  The diagram shows a pair of homologous chromosomescfazlxb w 58o9c w-50xdxh y02.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed i 4 4yicwokuudyn7j4 :9n an experiment. Which row shows the expected phenotypic ratios of the of4o djk4uyw: y9u 47cnifspring resulting from this cross?

  In some animals, the agouti allele cauee/i 6hdwa k fbf2:6a jzx/3u;ses individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have fadxa/3hwfe6u j2ze/6b: ;ki 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 plantsktkoew; 17 q2f71a 04sj eepur was either round or wrinkled. The results of an experimental cross afk;0 ee 171e74j2pw u troqksyielded 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 fruit trb .no 00c3 ih1dwv8sfly (Drosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertit0hd0w3bo .ic n1s8vrlised oocyte of a fruit fly?

  When does the random orientatio w) wulbql9 r(u:j-en2n of homologous chromosome pairs occur?

The majority of the genes in the human genome have al 4abz6cm l*4whready been mapped, meaning the exact locatioc mzwl4ahb* 46ns 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 defz2ao(riqc/ c bs 2c2v-aoq7gc1) nt(j inition of linked genes?

  The diagram shows a karyogram of a brown male rat5v 0sa 4z)bjwd,pmxc/qp(jf5 9 n;hco (Rattus norvegicus). Which arrow is pointing to a pair of autosoczxo4)w950 ;cph,pa(b/jj mf sd5n vqmes?

  Mendel observed that there are two possible variations of flower colour igl5 *or,1gxvcq; jj l8n pea plants, purple and white. After a genetic cross, the ratio of plants with purple f5* x r jjqlcv1g;g8l,olowers 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 ajmwe849 c438 cxgljy1991j lyxw9j e348a4 gc8cm.

  Which of these traits is an example of continuous variatio2q7hmf:tba2c n?

  Which row correctly describes diploid pm 2-g7jna9cy and haploid cells in humans?

  The following table shows the diploidq (m*cgcs an3dk- je*2;7h5et ru bn+q chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia isu+ 1zr,+e0ki )h cgweq 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 had9l9s4est 366mun lbxd a child with blood type O. What are the possible genotypes of the biolog4b n9els 6 3sd6xtml9uical father?

  Which row shows the correct annotation of the allel0u9 t igkcm*7 .p3jeaqes for blood groups?

  Which of these statements are truexts d5 ,v4lzma1eq1 .e 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;x/u r0vh hepmvu3nj+3nq6rq6 m ou3aoi 5x-+ of malaria acrov3 a mhxepun60h3q+ 5x/ v r-oqnr+;6ujouim3ss the 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 przewalsgn pw q5.3auz+/+vmzfkii), 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 dominqu mv5zap z/f .+g+n3want 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 0nf,9bs rf9g cl.,m nwlinked and unlinked genes.

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

Sickle cell anaemia is caused by the+wf zh: :3/a0, g,fs cll)lsz/wh o(hsdf mnd. 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 between a male cat that is homozygous for l48 q 5p5fw9h 6qpxhydbrown, long hair and hxl5df 9qpq4y58hw6p a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the alafn::7ccsy 9( 2 p.bamiby *du*.i lpnzak/n 9lele for diamond-shaped seeds (D) is dominant ov9k p.: /dyalnib(scic92an. zpf7bn* m:yau*er oval-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 porcellus), long hair (L) is dominany zt n,mp:wki-9,/- rorsdko;t 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-squared test (χ2) was y n zd/o,r 9p-wmro :,ikk;-tscarried 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/f unhz r0q7:qe(wgjb u8 9k7bnheritance of the condition shown in the pedigree chart bf 0:/juwk7r7qg qz 8hub(ne 9below?

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

  Which of these statements about genetic disorders is/are cobf8zohzg9u d2qv13d5z v(1 fcrrect?

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 norma9bmfbdm:q/i)44p.zn ln2zall distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  What suggests that the inherk6 cwf+p23 ajzitance of the disorder shown in the pedigree chart is X-linked recessive and not autosomal re+6p ac2kzw3fjcessive?

  Different species of living organisms hkib+d8+.kwjw ave different numbers of genes characteristic to them. The table shows the estimated number of genes for five species. .wi+w+d kkjb 8
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 characteriv ,jjeq.-9 pcsn+ jh/nstics of pea plants, including flower colour. If tn-+e.jp c,vn jq jh9s/he pea plants Mendel was studying 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 alj/x ugipz-o;8 x3zf+ biological female without hemophilia have a daughter without hemophilia. What are the possible genotypes of the daj8f z i-zluxx p3go/;+ughter?

  A dihybrid cross was carried out between two sunflower plants (H.h12 jpmxtle +r-ks l4lx3l6belianthus annuus) to see if the genes for seed number and seed shape are link s 1 +hm4t3-rbellj6l2x.kxp led. 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 typ7q8fpdcpl1 g02pm p3 pe B can have a child with blood tq7pp p 0l fd1gm8pc32pype O.

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

3.Explain the role of inheritance in genetic diseases.