A man and a woman have a fz g468j7 ijue,gf v9cdaughter and a son. Their daughter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for the bz9vfeg jgiuc 7648jf,iological mother?

  Which diagram shows the sex chromosomes of a somah)x4p*rdn j c9-q5lrl tic cell in a human male?

  There are two alleles for flower colour in snapdragsa)fqmo5b2 8h b(ig r3ons. However, the result of a cross between two heterozygous plants yielded ai 8qfb5s o)bmhgr32(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 the correctuz/ :ut//02eg4 lnilw3ewtm w definition?

  Which of these statements is a correc r8 ;d2q7t2 dlweaq1sz2ywt.ot definition for a gene?

  The diagram shows a pair of homologous chromo gfwv s-)ew5s5somes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossedzz/u q4( a1a kb3zx(hpvu ,tz7 in an experiment. Which row sh u tz(uq(/z7k4p,zz vx3a1h baows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hat:2+lg .eleihb2f n2p01eko1l ba o,airs to have a banded pattern. The non-agouti allele causes ha1l: 2nlf2gko01l th .iba+e2oab ,peeirs 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 plants was eith3-wfhjl ru*r2wkj,4v9w bs02 iq (yuoer round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offsqrsb i2hjv9u4,3 w0u2w(-kyl wj*ro fpring with wrinkled seeds.

Which row in the table below states the most likely genotypes of the parents?

  Neurons of the fruit fly (Drosophila me sg;x/kt yl)z5zurgzy02kr (+lanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fruit fly?l kkz;yt/( gzug0y)s rzx r2+5

  When does the random orientation of homologj+vmr + emf70hous chromosome pairs occur?

The majority of the genes in the human genome havt p ggitq7frqb/0k49 *e already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one*g0gkpr/7 itb q 94qft 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 definition o o4qxn8r ;txi30.zg hpf linked genes?

  The diagram shows a karyogram /,snu r/cx8,5wkfgye ua9 r9t of a brown male rat (Rattus norvegicus). Which arrow is poic,59g t /8r uyxfrwausk,9 n/enting to a pair of autosomes?

  Mendel observed that there kg-,dvid ; j(,14g sz)w pbbjfare two possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple fl 1gg,) w dsbfj jvb(zi-4dk,;powers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight of children born isn: gkccu/ycgo y ..)*n London in 1991.c gc)u:..co/sk n y*gy

  Which of these traits is an example of continuous variati z0m1twxfq,7 gon?

  Which row correctly describes diploid and haploid celw soxi,+o /+v tcdq9p+0/nevh ls in humans?

  The following table shows the diploid chromosome number of a rang 0-pkgs2i pt7b;vz6gde of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allele (cd i7myyf t*6.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 type O. What arev)kr *ii4my pg6+w(pi the possible genotypes of the biological fathe pkm+w (v4yg rip6)i*ir?

  Which row shows the cor mr/k xt)u5ur5gfi2 -orect annotation of the alleles for blood groups?

  Which of these statements are tylp-nm:/rz/ qrue 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 qx /puhua xx rku85,,)oil e35sickle cell anaemia and the spread of malaria across the continent of Afr5,kl8e5 3)xa qurxhp uuoxi/,ica.


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)ms/p8 i i5f7ai, 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 dominant to one tone (f /8ismpi75iap).


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 *x,3n3ovyubym2 gb:y*1qze b linked and unlinked genes.

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

Sickle cell anaemia is caused 1bd)dk 2tw6sr 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 fk+ dr c9*jgkz0or brown, long hair and a female cat that has bzrkg*d09+ j cklack, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum ofizc7rk p9ju xx (l1xdzu00v) 9ficinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped r 091kixzu)l7dc px0 9uxj(vzseeds (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 dominant to shorqa ) q 5q:up5)vzyhxplz1f0- ct hair (l), and curly0q)pyuzqzfq: x- 5pv5la h)c1 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 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 inh-psd:dq0p1k7yoj18g w v o8ygeritance of the condition shown in the pedigree chart p1 pvd kg:qdw-o8jsyo0g7y1 8 below?

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

  Which of these statements about genetic die0/sthkov k3vs 7b1 4ssorders 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 traitsgxg7 )m,yrwyge g7zrr (a+4ifs/0h2c 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 pedigrev5dyff6/m 8.gk l;ng ,gjd wa8e chart is X-linked recessigf8/lmk8 w6y., d naf gdgj;5vve and not autosomal recessive?

  Different species of living organisms have different numbers of gef ov7k(jtwc+;nes characteristic to them. The table shows the estimated number+(;v cw7ojtf k 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 colouham )4 ,; gst5fgbzz+3 at1kujcet0h2r. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statements wj+t3cf14 at h;hggembzs,5zu)ta0 k2as correct?

  A biological male with hemophilia and a )qy4288,ol3 *cxc av 2ymjgqka zca8q biological female without hemophilia have a daughte2yq8macgc2zac38v ,xlq *kyj4 8 qa)or without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Heliafe c5s, fl1/iknthus 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; whesc5kf /i1f,l at does this indicate?

1.Explain how parents with blood( syusou4mr tv*2bo ;h s0;ma:s,o7zo type A and blood type B can have a child with blood typez;uo*so osu:vm0ary4oms s,t(7 b 2;h O.

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

3.Explain the role of inheritance in genetic diseases.