A man and a woman have a daughter and a son. Their daughteq z;wu/r22j hkr has normal vision, but their son is colourblind. Which one of these genotypes could be coruz2q ;kwj2 /hrrect for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human u-:;o iw2;*6tvovngzm*g pgb male?

  There are two alleles for flower colour in snapdragons. However5bic; o .s :jcsp;qx-s, the result of a cross bet5bxp- .qs :ocjs;sic; ween two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matched to the correct defh/h x5b bttbsy)5.izxm j e;wvbd2,q d26+q*einition?

  Which of these statements is a correct definition for a gen -x dz07:r6kcwbwdv9a e?

  The diagram shows a pair of homologous c(sop74 i u8cq yho; c)xp:)w .qwukz-phromosomes.

How many loci are shown?

  Two individuals, heterozygoulbj2 rm(ek(*9sld1lrs for a specific trait, were crossed in an experiment. Which row shows the expected phenotypic ratios of the offspring d (j 9*lrrmlb21lesk(resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a6:-xsf mf)hd3/m popt banded pattern. The non-agouti allele causes hairs to3 xmhffpm-dpo)6: st / 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 v (+g)msqr s6tpea plants was either round or wrinkled. The rev r)6t+s(gmq ssults 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 fruit fly (D*6s 1ep xdyc4grosophila melanogaster) have 8 chromosomes. How many chromosomes are in a fertilised oocyte of a fru sgpycxd4e *61it fly?

  When does the random orientation of82 s hzqof wbs pa,h9h43x.pt3 homologous chromosome pairs occur?

The majority of the genes in the human 8mh,i+htb.-s g-dlhq genome have already been mapped, meaning the exact locations of the genes on chromosomesih+.ght,h8bml- sq- d 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 definition of lin :k:0di i(m+y sbdawu2ked genes?

  The diagram shows a kary9r0w:ndfh rsm+(xq-: 9//vfjct t zj oogram of a brown male rat (Rattus norvegicus). Which arrow is pointing td mjv/ c: -of0(q9nzjhsw/rt f+9rtx :o a pair of autosomes?

  Mendel observed that there are two possible variations of flower colouh s*zm ;tbp h+ ghqq3b,gzfrtt*3*u59r in pea plants, pur3;br9gh*3pqg zqht*hfbz* tsm,ut+5ple and 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/r,dds;m6l:0ylc f eq birth weight of children born in London in 1991.cr/le6d d fs,l:;myq0

  Which of these traits is an example of continuous vw5eqf 6s9kvssv;cvt5f f4 ,;xariation?

  Which row correctly describes diploid and haploidqo pxwwgwh/-9, fq;f6 cells in humans?

  The following table shows the diploid chromosome number of a rangxr )q 8*9 2hoxkwafiae ;,lf7oe of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allez . wkfc8k9zc6*vwj 7;djud-cle (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 t*ue4, s* a7eo/ 8oerp5t*rkmcbph;zk ype O. What are the possible genot zet, o5e*47*mp 8ph/*bs;uarekoc rkypes of the biological father?

  Which row shows the correct annotation of the alleles for bloodn4t 5( .idznzbkl5 gt0+osz/l groups?

  Which of these statements are truuwzhqrd4i18 0dye0* be 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 6gm t w0pmsv 58 fj5dp4zdppd kv/9;i-and the spread of malaria acrtd-vkp ppi6/mj4 w;f 9dzm55pgs8vd0 oss 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 isy.zs1 zie *ac7niov.- determined by a number of genes. Brown colouryv o.7.z-is* nze1aic (B) is dominant to sandy colour (b) 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 linkefg6 a6-plamq 3z e-pv;d and unlinked genes.

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

Sickle cell anaemia is caused by the a1r p,o0xacrb9 llele 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 n*g*me mhb2pr0 +mg9flnkwd*v*.wx3 cat that is homozygous for brown, l d k3mlnv*f*+wm.0bn2 x*wgh*rp9m egong hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officina7gr /mb5-g rscle), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominantc mgrb7/5sg r- 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 55y8ass5fco dn:nw.g (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-haired guinea pigs and female short, straight-haired gu.sw oag : fndn5sy55c8inea 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 in the pe)f:eb s,yux 85nhjsc-digree chart bels,)bhnx5eu-f cjys :8ow?

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

  Which of these statemen8k;inxah, lft i op/q 99r8c2xts about 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 sho8js)5q ;- b1zwxlszxlw 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 inh( ckm/q k3puc1eritance of the disorder shown in the pedigree chart is X-linked recessive and not autosomal recesc/uk3(p1m kqc sive?

  Different species of living organlffy0 :(;nbd mhv u1r9isms have different numbers of genes characteristic to them. The table shows the es1:l9mh udf y0rn vb;(ftimated 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 fl6+d ahi*9asug*jk +z s6wmn ;xower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statementsnax+u66 9g +h s i*jw*zma;dks was correct?

  A biological male with hemophilia and a biological female withou o02 ldx:x-i gmxe:j6;8h zmtut hemophilia havex8 dgio;:l0 :6mjmtxzue2h -x a daughter without hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was c.k 6vdoo4dlzpn 4ahl mpu/jpmd9 397l6 km; +carried out between two sunflower plants (Helianthus annuus) to see if a4kpdm 4u6dnlvmo cmok.j9lh76 dp z9 +l/;3pthe 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 value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood tk t,udj v80ta*+m ,eh1ae2/anmg4sj hype A and blood type B can have a child with blood tae+ 8 g4hde1t*u0jn, j/mav ,s hma2ktype O.

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

3.Explain the role of inheritance in genetic diseases.