A man and a woman have a daughter and a sonawyk3reu);k 8 . Their daughter has normal vision, but their son is colourblind. Which one ofk w8ae uy;3kr) these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell inlc,z: r/2t qhg a human male?

  There are two alleles for flower colour in snapdragons. However, the result otqn84thcsh5i f96 2f yf a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanatf46sn29cy ti t8f5q hhion for this observation?

  Which keyword is matched to the correc82ek;u hdqayx cuieiz/;ss 5) 4zd4e:t definition?

  Which of these statements is a correkic:a4u7) vg c.j w-tfct definition for a gene?

  The diagram shows a pair of hoqq,4. np r;ep1h )jidqmologous chromosomes.

How many loci are shown?

  Two individuals, heterozygousrb 6 svpp2ow2x 4pxgu-d0 zyxh3-v/i 9 for a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring resulting from this crh2x 0spb zxv/ 9dyxvi p2og-u3-w64pross?

  In some animals, the agouti allele causes individual hairs tog7 e*t )oa9rnw have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individun e 9*7w)rotgaals 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 l/6eivvj 1/ mrthe seed shape in individual pea plants was either round or wrinkled. The resulejrm / v1iv6l/ts of an experimental cross yielded 315 offspring with round seeds and 105 offspring with wrinkled seeds.

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

  Neurons of the fruitvxd4rvl n c+9 hh.4nm9ntc;i4 fly (Drosophila melanogaster) have 8 chromosomes. How many chromosomesm4;+v lnd4nhxn94tcc9 .rh i v are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chromosome +x57e5ctw rmd pairs occur?

The majority of the genes in the human genome have already been mapped, meanp:/ :mzjmt. dj t)ig1ling the exact locations of the genes l igdzmp./jmt 1:): jton chromosomes are known. The diagram below 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 defnr2rfo a 0/i/tinition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus noeyo;mpm63 b-m rvegicus). Which arrow is pointing to a pair3oe pby6mm-; m of autosomes?

  Mendel observed that there are two possible g/nt ze/*:r 5gslr im7ogu0e6variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of planlo0 ggu6i7zst/en grm er5/:*ts with purple flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequnp7ehic8m*ml7c:vy j)2px icf7 sb6 vq,2e9kency of birth weight of children born in London in 1991. hf28* vic:e7 7mc6jb9x,)iy mp2c7pv enq ks l

  Which of these traits is an example of continufuo4f ndktx. xs 97:8cous variation?

  Which row correctly describes diploid and haploid cells in humans8re3m1+j/ebmv zhb1 v+ xwa r/?

  The following table shows the diploid chromosome number of a range of9.04 vzamfreomo pi,4 species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allelvi5 cw:e.vsde39 xn1 s vet6/pe (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 i1)mdxard-xq f g;k)tix8*l 3blood type A had a child with blood type O. What are the pfaq xx -3im ;dlti)1r *)gxdk8ossible genotypes of the biological father?

  Which row shows the correct annotat vth3yx1 dmrpa 6wsqwo:hn1+f2+ 2cl(ion of the alleles for blood groups?

  Which of these statements are tr bm xwcb(w76xixo; 0i((i 40-ztlvvhiue 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 sp k+avrwv(b+ p:read of malaria across the +barp k(:wv+ vcontinent 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 numbeqro/ud,2bz8 qysk6h2 r of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour , rsuqyo8b6k2d 2q/h z(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 linw;dy; r:09z4mfbt69jqkmvec 8 b ayo.ked and unlinked genes.

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

Sickle cell anaemia is causedi qna/ur)nv- ur(q04n 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 h,gy7z e.t h3px*vl8dgomozygous for brown, y8 *dv,hx73g tg.ezpl long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Tarax /bdix-nb1*3p v6scvmacum officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is/bn 3*v1m6xpi- sbc dv 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)yx5m 5 sf;jg/: jshf;b, 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 heterozygous long, curly-hairs;g;jf55 jhf:s xmb /yed 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.75ammf c++iqui;w1oe adb1e h8xnf - in the pedigree charthfwx fea8 1aecdqi nu+mo-;.+i 7m5b1 below?

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

  Which of these statements aboujgu 9isy(9oh +atv 7go1e;s2mj oxo09t genetic disorders 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 disl cw+d+mrm4 b0mxuz6q 77r z+stribution.

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 pedigreeq 1pz qi l,ni8xia.::x chart is X-linked receqa: xipzx 1iq,:n .i8lssive and not autosomal recessive?

  Different species of living organisms have differe t6c.arhrxp+x nyl32;m2h1f bnt numbers of genes characteristic to them. The table shows the estimated number of genes for five spepxr.;3rybhh a62+xc 1ftm2ln cies.
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 plantsd5ahw28 2 3cgj1jbiwe1fe o-y 7dq ck-, including flower colour. If the 3b2k- oy5fj 827qi-ew1dehcdacj1wg 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 hemophil x43ysk-4ia/yg,l6fb5 cjtp m ia have a daughter without hemophili36kmf-/ia ly4c t5b4yjxp, sg a. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annubh jn u5e +p (lu*2befd9q05ipus) 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 cabbed+5 ( 5hu2*pu qinj9pefl0lculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with bloodl l q:os +6v r7jf7i2dvj/8gag type A and blood type B can have a child with blood typesq6 a iogg8/jvflv:7 2 7rj+ld O.

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

3.Explain the role of inheritance in genetic diseases.