A man and a woman have a daughter and a son. Their daughter has novt2ci7i ru9 poa,2o(do: 6) crbsc(qormal vision, but their son is colourblind. Which one of these genotypes could be correct for the biologicalpuiacq s2d,v( oo)o(tcob 67r rc2i:9 mother?

  Which diagram shows the sex chrom+aslbr9k p 4cdn5.* r,zhe ez:osomes of a somatic cell in a human male?

  There are two alleles for flower colour in snapdrago.rh6xz;))9aqm gr j*dcpbo 34/n ar tyns. However, the result of a cross between two heterozygous plants yielded offspring with three different obserg d.)6nqr) yp/ta9;c x hma3*ojz4r brved phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct ded p0beea x97i;finition?

  Which of these statements is a correct defin9re *0itcn( 3pbkr,d4qxp ri 1ition for a gene?

  The diagram shows a pair ofwwp6uhw / bhsa:r;)kl,*o hn5mvf70 a homologous chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, wer6u b.2z4fxabm 7e7au paded.yq,; 6mre crossed in an experiment. Which row shows the expected phenote.a 6baqdr um 7;6z7xmf p.4abdu2y, eypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a banded.gj 3ua4i0-vl2 cfxpi 3+uz.tu bd)ve pattern. The non-agouti allele causes hairs to be a single colour. Individuals 2-3a iv)0 tg.fpi lxbujz+uv4 ed.c3uwho 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 zz;; dc8pqor1 pea plants was either round or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkrz ;pqoc1d;8zled seeds.

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

  Neurons of the fruit fly (futb d kd01nfz4 7*g2aDrosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a frugff*2d7un k1 dzt4b0ait fly?

  When does the random orientation of homologous chromosome pairs8,;brhwti k7pnni)x6 occur?

The majority of the genes in the human genjy+9um1 d+n y ena +bfc-s1;qkome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows ;km d+yc- n+b1j1ynf9qe+us aone 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 of linkedi/*4qiww2 y go genes?

  The diagram shows a karyogram of a brown male n5rsxet-l qu669b l1srat (Rattus norvegicus). Which arrow is pointing 5ul6ssqr enxtb 6l-9 1to a pair of autosomes?

  Mendel observed that there are two possible variations of flower colo.:uk:c lx fqr jicf:8 h:yyq0w7lb11cur in pea plants, purple x::kq.8yf 0j:cr7 l:ybchfc iq1wl1uand white. 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 Londo1(ur. bg6e kman in 1991. bg1 6(merak.u

  Which of these traits is an example of continuous variatio mw-+4xrtiq( o y *q82uxc1fibn?

  Which row correctly descrikyag-w5 ty4-x,u pqa .bes diploid and haploid cells in humans?

  The following table shows the diploid chre(lf7b6av ueu3d1j g+z(m 7sjomosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia cb,ivrjzo,(be u*ofj9 1 ,r (ris 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 ha;;6o*ymuji m cboi0r 6d a child with blood type O. What are the possible genotypes of the biologicim6y o6j0b;cu ;io*mr al father?

  Which row shows the correct annotation of the alleles for bloo90v4zuf m 8 xdks*(cxqd groups?

  Which of these statements are true for /t5*rm8)i505nzeuid xbzb u halleles?
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 spreay :j nh0l5r;rid of malaria across the contii0rj ; rnh:l5ynent 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 d b 5g)f)3qff;hpdz9 3lwqlyv*etermined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dominant to on35;9))d 3vqplfzfg y wlbhq *fe 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 linked and unlinked *q6c vdi9seej1 z+ j.ab avvswwc)ryy 46 :76ggenes.

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

Sickle cell anaemia is caused (yc2 v(8qc.ev1yhqcm mukh -8by 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 showzng/vnp4n 4qqpi 4*5 ts a cross between a male cat that is homozygous for brown, long hair and a female cat thattpzng /q5v4qni44*n p has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum oz/bf2 tz7;dec25e8 rlsnsq *rfficinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the a*;ql t ern/z8dsc z2r7bef2 s5llele 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 porkwv q9+ bga-zs446fvj cellus), long hair (L) is dominant to short hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out qwbz j96s4v- a+v4gfkbetween 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 inheritance of the con/s/2) )bveunjtoocvjs ,s:+ spr u)d.dition shown in the pedigree chart belowvj/+s )2ope.u ) /s:s)u rscvj otbd,n?

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

  Which of these statements about genetic disorders is/are cx15utp w - 496lszg8r(wdwb aiorrect?

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 1.mug7s /ldb 7bo:odv 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 pedigree chartj d729 fwk5qrs is X-linked rec rk2j7d 9qs5wfessive and not autosomal recessive?

  Different species of living organisms have different numbers of genes zf0g2p8r 1 fnocharacteristic to them. The table shows the estimated number of genes for five specieponz81rfg2 0fs.
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 characte+zl8 *gzvz9vcristics of pea plants, including flower colour. If v 9v*8c zlzg+zthe 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 a biological female without h .e cr)giai.:gemophilia have a daughter without hemophilia. What eggi:.ri.c a )are the possible genotypes of the daughter?

  A dihybrid cross wasw./ vlwd9o/ 6j1vzrdh carried out between two sunflower plants (Helianthus annuus) to see if the genes for seed number and seed shape are linked. The critical valuhj lz6do.9v d//rvww1e 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 type B can have a child ,ihhdh ij /;h0with blood typeh0hi jhh,di/; O.

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

3.Explain the role of inheritance in genetic diseases.