A man and a woman have a d kb8qdc-u1-g qy*vnw :aughter and a son. Their daughter has normal vision, but their son is colourblind. Which y-wg81cbv k-n :*quq done of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of ali payf 4e;*3 ib8k*bqs*xf4d somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. Howetub cx,r./ljfd/z 3;a ver, the result of a cross between two het. u/zjr ,f3a/ldtx c;berozygous 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 matched to)66 e;km sr q*s0pl3np+set5m 4vwlry the correct definition?

  Which of these statements is a correct definits : -x0zpib,fr6 veq b-4-zmdpion for a gene?

  The diagram shows a pair of homologo/mcik8 * 13meoneq1pzus chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed 4kspnz;(rca 6 p52tkein an experimen(kpnr2;k 456 tzcaeps t. Which row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes vcav teg0(;u 1rztf0( individual hairs to have a banded pattern. The non-agouti allele 0g e t; tra1uf0z(c(vvcauses 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 plant4t*6ahdoekr -4:l g uis was either round or wrinkled. The r d:e* u-44ogi6htlkar esults 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 fruit fly (Drosophila melanogaster) have b7tc+8rz-r(r* z2z d vvnp2rn8 chromosomes. How many chromosom(zcrntv zn rpr7 +2-2b*d r8zves are in a fertilised oocyte of a fruit fly?

  When does the random orie o)sd3.otj: rentation of homologous chromosome pairs occur?

The majority of the genes inxc mw(8a8 zdu1 the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one represenzc(md8w 18xuatation 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 genesbq6qal/.nb0*i yn zq 8?

  The diagram shows a karyogram of a brown male rat (Rattus norvecey,a/(eyhf e-4zyux98 d 3rsgicus). Which arrow is pointing9hy dexee 8 azfy4r(c yu3/s,- to a pair of autosomes?

  Mendel observed that there are two pj 4xurel37h ni*:1pe wv u*q*sossible variations of flower colour in pea plants, purple and whitlnpe uexh* 1jwqi 3s:*7*4ruve. 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 1) 3 ;z*ifxma3enu th3qsg1ccof birth weight of children born in London in 1991. g;m3)3xc3t sea1 zcui1nqf* h

  Which of these traits is an exa)halw77dstbxtb, 6nhk6.:tx nge )+omple of continuous variation?

  Which row correctly describes diploid and haploid celqg v5kosa7r rfl j:f0 150+uwrls in humans?

  The following table shows the diploid chromosome number of a range of specie -y6pf/6sft f-xde18 *yytqsgs.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive alleleev 48*o jor(jpk u(gv7pmrp n3k+p1u) (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 withk 1s6duku: yhhl, 6w:y blood type O. What are the possible genotypes of the biologic: wdksku6y ,h:lu1h 6yal father?

  Which row shows the correct annotation of the alleles foo+q fc 8a1cl-vr blood groups?

  Which of these statements are true for allele-0,uu f 09;xpmfiyhgbs?
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 oft, a-;,a zs8:tu naknn malaria across the cazkana ust-;:,, n8tnontinent 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 a og 1x7st5mj+is determined by a number of gext1mg o7js a5+nes. 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 li,lqnr 6wy -4muet 4j0 b,wttiho mf*6+nked and unlinked genes.

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

Sickle cell anaemia is caused by the allele Hi-y1ul pt ,iyxzteasc(j u t753hw-30vax:)rb$^S$ . 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 1qalhi2f:jt o+mk- r (t3-d uinm6 3tdcat that is homozygous for brown, long hair and a female cat that has black, short h(3f-hj n:q32malt t-1+d 6id ukit mroair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum offici9jzpsfi7*zn5 nale), the allele for diamond-shaped seeds (D) is z5f9j7nzsip* dominant over 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 dominan;cz41 6h xcvt p02qxjn3+kpo ct to short hair (l), and curly c;pc 21+z0xqvh3 kop6xc n4jthair (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 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 inheri+i rj.ztz (e*4reqe q4 kt+e(utance of the condition shown in the pedigree chart b rzjtu iere t+qzk4(*.qe+e (4elow?

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

  Which of these statements about genetic disorders is/are correizhc ,0*bxk1 lct?

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 distrh2ks (fe + xfpv2.kv8tibution.

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 inkzz/6jlll0qaf2d(m5 the pedigree chart is X-linked recessive and nm56qdjf 02a k(lzllz /ot autosomal recessive?

  Different species of living organisms have di7)swx*r npgrac06 hxlz;ez45 fferent numbers of genes characteristic to them. The table 6ra 74c) hxw zz ;0pn*gsrxel5shows 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 colige4e n 2adb.n fq*y dqy4,:6ewz46odour. If the pea plants Mendel was studying can only be white or purple and follow idq2qz e gn,a64e64wnyefb *dd.o4:ythe rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemop;q,kaaq o1g +yhilia and a biological female without hemophilia have a daughter wia1yqo gk,+;a qthout hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annuuswznhe7*;- ieq ) 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-squared test was 10i7;*ewqn-h ez.05; what does this indicate?

1.Explain how parents with blood type/q ua .xg eyco),x)um2 A and blood type B can have a child with blood typexeocu.ag))xm y2q u ,/ O.

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

3.Explain the role of inheritance in genetic diseases.