A man and a woman have a daughter and a son. Their daughter has ny*4o 3/f+qo+s kjk7* cu zufhdormal vision, but theirf7h kfc*ko*/ osud qyu+4+3jz son is colourblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a heru 1sfh.mg)8x+kov 5-uhuq/uman male?

  There are two allele;;vy w1/ o8b0-n pxymvi 7szvns for flower colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, y;pw8y /vno;i-m nv szx7vb01white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the corrlqpo u1u(l8yr a74n dt5hs 9-dect definition?

  Which of these statements is a + 10w*lyzhznexhys: .correct definition for a gene?

  The diagram shows a pair of homologous chromosomd u+-np32tys wes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an exp0.h/ /whi: g umd8cpaceriment. Which row shows the/chd. i8gm0a: u/ phcw expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agout0hmmlr lx8(kih+ ao. 2i allele causes individual hairs to have a banded pattern. olah.mxi0+( 8r2mkh lThe non-agouti allele causes hairs 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 either roz-3h)m ;uavq vund or wrinkled. The results of an experimental cross yielded 315 offspring with roun)m au vh3qzv-;d 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 p39ctxi2;r qamosomes. How many chromx i9tq2 rca3;posomes are in a fertilised oocyte of a fruit fly?

  When does the random orientahr9,n9) b ;ea 9vkvkaation of homologous chromosome pairs occur?

The majority of the genes in the human genome ha 7w dxtblo5420uni x)l9fsys( lf62rhve already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of a homologous pair of chb (227huf6wso50ixl tlfx )dl4 nsyr9romosomes.

1.Define locus.

2.Identify the number of loci shown in the diagram.

3.Distinguish between gene, allele, and locus.

  Which is the correct f (nv-6s5rcp.4pa oao v./puqdefinition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus nos2v3y (v: q5djg0bx vbrvegicus). Which arrow is pointing to a pair of3djvygq bv s502:bxv( autosomes?

  Mendel observed that there are two possible variations of flower colour in uwso7x+a: c 4z+yn.sdjf6b e3pea plants, purple and white. After a genetic cross, the ratio of plants wit7 b3 :usjofdy sxaw.e6 zc4n++h purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the f 69qd/xr+9fuwa uu7rceus: 4mrequency of birth weight of children born in London in 1991. sum 7r+ d6quuf/ 9:4wucexa r9

  Which of these traits is an exaojiy *v*zxl9)mple of continuous variation?

  Which row correctly describes didvc b6 p-xsaj;luq51x 1c:baq-jt 6)qploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a rang.uo+a9wdnw j 9*f9s 7pcsu :yxe of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive aluv4t m .fh+vijbb092m lele (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 aslw )3/2 thbrpmq21vq4 jp0sk68bduv re the possible genotypes of the biological fa km)l0t/8s 3 p v p4v1hqrbj2qswd2bu6ther?

  Which row shows the correct annotation .xbdp24ch95 r,r43cefcs x vb of the alleles for blood groups?

  Which of these statemenlh4efbw50 oi de 7x+.ats are true 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 sickle cell anaemia and the spread k h;brqv;q6+bxanfhd) m0 -iay. 63kyof malaria across the continent o f.xm +ayn;3hkd6kh0b yq-a6vr bi;) qf 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 przewajy d6 8nv2/ l4vini5mylskii), 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) isy/nvv n 5j8i6y4mil2d 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 and4 toarljl0b5)qyxw:n+ 5gwq 0 unlinked genes.

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

Sickle cell anaemia is caux;q/4x wb0mf ised 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-84xj ahq-qe o cat that is homozygous for brown, long hair and 4ej oahq8 q-x-a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Tarax. lh.o:wdb. hlacum officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for lodlbow.:.lh .h ng 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 short hair (l)q rvui945 zg+k, and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous long, curly-havk 4iq5uzg+r9ired 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 inheritance6e n6 amq*tq44bzy+lu of the condition shown in the pedigree chartm au q46+el*4 yz6qnbt below?

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

  Which of these statements about genetic disord xj :*ckqo.ee9ers 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 dist:-wqeo4-a 3r:xqbsb8+ *)gqesj i xacribution.

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 pegi5*7v v *ipfhdigree chart is X-linked recessive and not autosomal recess7phfv5ii g*v *ive?

  Different species of living organisms have different numbers of genes c3oqa c ijy0q,/haracteristic to them. The table shq/0i y3 jqoca,ows 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, including0yh5/ faopt y) flower colour. If the pea plants Mendel was studying can only be white or purple ata y )p/0o5yfhnd follow the rules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biological female without hem 8)x:i; ybjtcysqu1*v ophilia have a daughter without hemophili;1c iy syu*bqvx) j:8ta. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between l ud m h68azw4):zrm:l4;uzattwo 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 ;za6r):m4z tdm 4luwz8uhal:was 7.82. The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents wi(:vcx8: y2egbp fh.hy th blood type A and blood type B can have a child with blood fbe(28p.xy :h :vyg chtype O.

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

3.Explain the role of inheritance in genetic diseases.