A man and a woman have a daughter and a son. Their daughter haw few5 0 alc*q+1a+d/)pjfryd*o5 lj( imns; ts normal vision, but their son is colourblind. Which one of these genotypes could be correct for the biorlt;( qjd*n w0l5 /jfad+i5aom*+p)y1sc fewlogical mother?

  Which diagram shows the sex chromosomes oj,cb qjmmv.asdxwq ku,.* d x+25**n zv2ql (ef a somatic cell in a human male?

  There are two alleles for flower colour in snapdragons. /.bvl+3vk wy wHowever, the result of a cross between two heterozygous plants yielded l/3+.b wvyw kvoffspring 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 definit ugyf2b43g.hi ion?

  Which of these statements is a correct definition forkcyn(5j7pyx :(u 9ccr a gene?

  The diagram shows a pair of homologous chromosomes. fz kjq2v0gyn43q01e4r.xl,a x yqh;w

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were j984lg n-e ykunk )-1mk2zy 0rp7crrjcrossed in an experiment. Which row shows the expected phemy)j -9jrlgcpk-y7z1 rr8n0 2nk4ku enotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes ieslmh+2llqth n ;*h;eh84l 4t ndividual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colou; l*lt4 sqh;m +h h48lelenh2tr. 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 individuok exe g**z6(zal pea plants was either round or wrinkled. The results of an experimentgz*ex *ek o6z(al 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 8 chro qds- c6l2+qdomosomes. How many chromosomes are in a fertilised oocyt d2qc6sloq-+de of a fruit fly?

  When does the random orientation of horug-f dg9o e2o;bt95ghl9 ;wfmologous chromosome pairs occur?

The majority of the genes in the human genome have already been mq d-89fji omg. n:,sopapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of9j.-nsq,do o8i gpf :m 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 li-qd.ot f *z9rb9kj 2ernked genes?

  The diagram shows a karyogram of a brown male rat (Ratt9a)l xfmg.yv)nt*. iv us norvegicus). Which arrow . vl)tfny agx*) v9m.iis pointing to a pair of autosomes?

  Mendel observed that there are two possible variations + ffn 0pe5fdy/of flower colour in pea plants, purple and white. After a g/yefnf05+d pfenetic 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 chi0 c ck/xaole22z; rr4kldren born in London in 1991.z2 k42ela0c/ ok c;rrx

  Which of these traits is an eo9xi4e k+ 4k/mguk5/gn k8d waxample of continuous variation?

  Which row correctly describes d98d4lzaap ij-v vdy2 9o4 x4nqiploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of speciesvjo z*sz*bm+ 4.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessi wloew3g(;1 zj pgc22cve 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 blood typo s(x:w9 xn vrrtqocu+58dj/1 e O. What are the possible genotypes of the9 xs n5vw1/tcj8u qd+r(o rx:o biological father?

  Which row shows the correct annotatinl 7okal y);becju**9 on of the alleles for blood groups?

  Which of these statements are true for aljqywo(1xda 35ea y*5aleles?
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 anacb is:zl;t* u;405g jcfubt6-igr y/v emia and the spread of malaria across the continent of Africi6vyciubs4gz -5;r tulgjt0:c f* / ;ba.


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 dv88o qbv;5bhe etermined by a number ofv8 b;q8bh5ove genes. 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 linke u52e 9thn.iqzih*fd 9d and unlinked genes.

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

Sickle cell anaemia 00f-yos7ec. sy ul aa2is caused 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 between a male cat that is homozygous fordb vr:*x f69f2vvpvt. brown, long hair and a female cat that9 :vvx6f 2b.*tdvpf rv has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum offr ipf/x1 )*xu:bzgkn td61 na3icinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short seeds pzxd3 : gufn6) r/an1k1b txi*(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 shortbg h6;je1,f4vd j6gru hair (l), and curly hair (C) is dominant to straight hai djrj g6;uv,6bg fh14er (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 inheri3y8 ai.e8 n 7veravkw23ai2f rtance of the condition shown in the pedigree chart belon3 8 32aa y7ra2ei w8.rkievfvw?

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

  Which of these statements about genetic disorders is/h sy n*g8w4qltfk+. ;mare 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 j; n-6az/z qxq ;-m,xf og9xv* map*wghvd,a,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 inhergdad(- dcu k-q;p3/wu94oe mnitance of the disorder shown in the pedigree chart is X-linked recess3(w-ekd4;adp9 u/m -uc ogqndive and not autosomal recessive?

  Different species of living organisms have differe l79r5fp;z r 9 d0zz;bnqmg/u5thpi2ant numbers of genes characteristic to tuz a57prhnzb 5 gp9dmqrl;/ z;t if290hem. The table shows 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 colour. I/mk4ts)lw gt-h;6e l ef the pea plants Mendel was study;m6l- htekg) lsetw4/ing 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 a biol5qhn n1s+0mv9cdbax/t8tw) xogical female without hemophilia have a daughter without hemophilia. What are the possib5 +80vcs)n w1dtxm /tn xhqb9ale genotypes of the daughter?

  A dihybrid cross was carried out betweenbgmq5 0m)moti5j d)o) 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 was 7.82. The calculated value for the chi-squared test was 10.05; what does tm0jto )bmi 5og)q)dm5his indicate?

1.Explain how parents with blood type A and blood type B can have a child wit7lwu*,aosaiz,mr 3l ioe-f 4jgg 7-: ih bzgaoi4wi-:,7 3o ,llu ame j gifr7-s*lood type O.

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

3.Explain the role of inheritance in genetic diseases.