A man and a woman have a daughter and a son. Their daughter has norm ch n6 li3d(i 9vj5vxs85c)vclal vision, but their son is colourblind. Which one of these genotypes could be correct for the biological mots5dlxv (h 5 ) l6iccn8v93jvciher?

  Which diagram shows the sex chromosomes of a sokp(yug)d ic,r jx:/e4matic cell in a human male?

  There are two alleles for flower colour in snapdragons. However, the result of ns+kdgj 8m5x(a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which imsnk8d+x(g 5j s the most likely explanation for this observation?

  Which keyword is matched to the correct definitiucc69zm pz:h;r4z) gu on?

  Which of these statements is a correct definition j0epzmv5x 0f btxc,(5o;54dw qp jjf;for a gene?

  The diagram shows a pa 9fxi4brbn/ /cir of homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygo wfy6w8,whc:nus for a specific trait, were crossed in an experiment. Which :6, fh8yw wwcnrow shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a ba7np: .qv4ts5xix;v nsnded pattern. The non-agouti allele causes h.qn i 57n:p4;svxv tsxairs 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 individ4da: 5yt:s- +k mfzhnjdc*+ho ual pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled sk++-a:c*jsn 4ft5hd yz:modheeds.

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

  Neurons of the fruit fly (Drosophila melan457wji:5 r:bd k g6kcq,do-la ii*io logaster) have 8 chromosomes. How many chromosomes are in bk7qdio* cik- :ajrl5w,gi45ld6o :ia fertilised oocyte of a fruit fly?

  When does the random orientation of homologous e1 xp3ethwpkasb,xb:4 1p0; wchromosome pairs occur?

The majority of the genes in the human genomu tpc, wu,sd;-e have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representau-ps, du;t,wction 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 correctiu) w x-m-zxf4 definition of linked genes?

  The diagram shows a karyogram of a brown muq- jw5;14bg2 /jcrlm0 nhsdyale rat (Rattus norvegicus). Which arrow is pointing to a pairy 1u;j 54mbdh2swc/r n- jqlg0 of autosomes?

  Mendel observed that there are two possible variatioor)ifd16 9z i m 0*2oo,xnihhins of flower colour in pea plants, purple and white.i0hoii92o, hifnx6*o)1 zmdr 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 of birth weight of children born in London in 1nma1+4vah 0pt j 1ms8v991. mj 1vta m4vpn 01s+a8h

  Which of these traits is an example of continu;et99sco 9rjgh 2x eu-ous variation?

  Which row correctly describes dipee; 9s3br6z muloid and haploid cells in humans?

  The following table shows i4c1ptkq c-gwx994nm the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allelec1)6 u 1t;xzj yfzbf5+jww h(i (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 are tl5/.:tfdbm lv, mzp 6ahe possible genotypes of vdza,fm./ blm :l56tpthe biological father?

  Which row shows the correct j6n*ap7 wx 6*a5ydzme annotation of the alleles for blood groups?

  Which of these statements are true for allele dek,lc, epm(z9ap5d -s?
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 incidenc:,oty r0l, lnfe of sickle cell anaemia and the spread of malaria acros,y,0: n rofllts 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 przewalskii), fur colour is determined by a nh e61km1biztxpnt8; vm 4kk9 ;)+ sthjumber of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to one tvtnjhb61zm +tp9xms48e itkh; );1kkone (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 and unlink52*rzoub/fvrib )/k2 bh1x gxed genes.

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

Sickle cell anaemia is caused by the allep rl(xpfa6*f9g: i f4bl-q,fjle 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 betb; oswi2:oiro+ ;ykw +ween a male cat that is homozygous for brown, long hair and a fe+;oy s ;2i +boki:wowrmale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxauu.y 5(lkm bg :pysurc/nmc17l7b+bl4eq g)* cum officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) ab)glb*ub:sy qu y(4 cpcul71ng/rm lm k7 5.+end 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)tm(c0l+0tj xt ws0 9jy, long hair (L) is dominant to short hair (l), and curly 0+wtsxjjy(9 0mtc0lt 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 inheritanwq ,yl cy (j1uuiqe+, sj 8j a(2;pio3fwjaf;,ce of the condition shown in the pedigree chart ,ws,yqju u8 3oe,a q(yil1 f pjc(ij2fw;a j+;below?

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

  Which of these statements about genetic disorders is/are correct? zcy/b ed:)cp *

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 c2-wcu, vsay d.unp-x4an 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 pedigrp 2dd :lrngn)l*x) c--g ymst0ee chart is X-linked recessive and not autosomal recessnrc*x2nylt:-sm)lp -dg d) 0give?

  Different species of living organisfbyl9wp - ;61qr4dac wms have different numbers of genes characteristic to them. The table shows the estimaw1; day9p cr l64bwf-qted 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 colo4y(h5jzg kc7f ur. If the pea plants Mendel was studyingfkj (g7y czh54 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 biological female /v 3) kodnoxt2f zsw64q2wai2 without hemophilia have vo a i/4 )z2dkn62qftwxso w32a daughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plalxnk /.x idb-(nts (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 valx -ln db(/kix.ue for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A and blood type B can have a 3vl6tjf (,a .h)tmrskchild with blf(3 .r, as6t h)ltvjmkood type O.

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

3.Explain the role of inheritance in genetic diseases.