A man and a woman have a daughter and a son. Their daughter has normal vi-0zjfu dpl l:6sion, but their son is colourblind. Which one ol-d: zjl06 ufpf these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes ofuy4 jkb4 7 h h4p6r1u6,ji kwuheit3l6fv (l4w a somatic cell in a human male?

  There are two alleles for flower cov 9wn2nr8- :j,ao yngblour in snapdragons. However, the result of a cross between two heterozygous plants yieldbay28 o,:nnrwg jn -9ved offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched elg :4; v0iogrto the correct definition?

  Which of these statements is a*f0.u(ccagl6 2rbb t pan8-l t correct definition for a gene?

  The diagram shows a pair of homologous chromosom; w3,azrn y;tces.

How many loci are shown?

  Two individuals, heterozygous fce a taqst(-s:..4fgfor a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratfa4.e:c t-fa s.t(gqsios of the offspring resulting from this cross?

  In some animals, the agouti tt -*;acr: funallele causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individualsac*r:;ftut- n 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 either rou za+v.mh ji)b;nd or wrinkled. The results of an experimental cross yielded 315 offspring with round seeds and 105 offsp)m;vz + .habijring 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 aeffh5(g s9cj+c03tc chromosomes. How many chromosomes are it5c ac0g+3(cf jehf9sn a fertilised oocyte of a fruit fly?

  When does the random orientation of homologokgqi8dhsl 1u95uu * r0.j 1vrous chromosome pairs occur?

The majority of the genes in the human gert-o7u , 4zpcjnome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram be4-7 ,cjtor zuplow shows one 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 lics*b7 kx1c ls*3c/wbwnked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). Which am y7iyn lq7.:wy/.6ud / ipcvjrrow is pointing to a pair o/my67iw y:yuqcnj pi/dl.7 v.f autosomes?

  Mendel observed that there are two possiblekegr y: nt0x(2 vf2zf0 variations of flower colour in pea plants, purple and wy0r(e nzvk t2 0xf:f2ghite. 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 f os4 .eesh)r :w:wnkm7requency of birth weight of children born in London in 1991.mwr owk4 s e)::se7hn.

  Which of these traits is u1 :znqq tz*m;piw*b xy,(m 3wan example of continuous variation?

  Which row correctly describes diploid and haploid cells in humans m) iv8cahz8f1; .6mrqzv1u.-ln lhou?

  The following table shows the diploid chromosome number li7qk,otx;q; 9pd+ eeof a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive akdv:m5d 7yk 6sllele (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 typr;-bo rx kry(/e A had a child with blood type O. What are the possibrb/(yorr ;- kxle genotypes of the biological father?

  Which row shows the correct annotation owt 4gtnmaowy 0/k57e)f the alleles for blood groups?

  Which of these statements are true fo6r3j zma7efviq 47znuy bu ()1r 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 sickle cell anapx5pv*.hd 4 i6ccet3 lemia and the spread of malaria across the con*pvd cc 3 6thix.e45lptinent 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 dete/bkadb+ 7)kbwn et+ k02np4jz rmined by a number of genes. Brown colour (B) is dominant to sandy colour (b0 wbba te42/kzb+ nj7kpnk+)d) 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 linked and unlinked gen9l wl*z 5cg , z9q4nq*w1nompjes.

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

Sickle cell anaemia is causedvvi)2 ungm32 t3s7 m+,azjyar 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 ak- tcmi8 8p erl+,s:uc male cat that is homozygous for brown, long hair and a female cat that has black, shor+8:peicct r,kls8 -mu t hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamos 9xv3(a v3cc9lueu/2d 1avzind-shaped seeds (D) is domi2u(evcz9/l u3sd3va v9a1cx inant 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 porcell d3e;r ,p 3uxu:t/dmzlus), 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 between male heterd ux33d l:,rm/e u;tpzozygous 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 condition shown *da3 o5 ,ovd4/ q3d2yc mzyfsoin the pedigree chart belo, qv* oo3/ofs 5m2dzydyd a3c4w?

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

  Which of these statements about genetic disorderp 46fbsfz0hxcbr4fv* u /8z s-s 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 traits can show a normal distrib cdb;k9 hgoa9ti)4 u9bution.

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 shown3k-t*jeiwr+ ;jl cw/bhi5d +t in the pedigree chart is ld+th;jet/w5c-j+i*bwk 3ri X-linked recessive and not autosomal recessive?

  Different species of l hq:us8*ek) (5d)zcbji t h*rgiving organisms have different numbers of genes characteristic to them. The table shows the estimated numbe)hrtzdj**cb) hk:(5 guqi e8 sr 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, includi6 nw,ek *e s0-bdu7jg zyhv 0gz+fv:v;ng flower colour. If the pea plants Mendel was studying can only be white or purple and follov 7;+f00sevw*- uegnzv j kbdghz,: 6yw the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biolowgid,kh e+iz+0 tu- 0qew5+fwgical female without hemophilia have a daughter without hfg+- w duee0kzthiw+ 0 iq+,w5emophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annu/yo l493it/x 9ugmp uius) 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 signifi9p4i/ 9ytxmui ul/og3cance level was 7.82. The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blo3x 8-ikn-5* ekwr8okf) 2v dr3suv eskk +*bxdod type A and blood type B can have a child with bloo fi3k8nr5 k8 eds rex-u3xvs2- ko*k+kdbw)v* d type O.

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

3.Explain the role of inheritance in genetic diseases.