A man and a woman have a daughter and a son. Them0/ uhuhzs 8k*yj4,wa ir daughter has normal vision, but their son is colourblind. Which onem/ 0z ,h48ukya sjwh*u of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic c*oe0-5 u pzhbz* bb d*y+.jmrxell in a human male?

  There are two alleles for flower colour in snapd x 8 k*d2hnknwb1 c;(wkzwx(9mragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for wxzk1(; 9 *xk(d ncnwbkh8m2wthis observation?

  Which keyword is matchedr/a s7j6wbw xuwt l1:0 to the correct definition?

  Which of these statements is a cormdiov734*x ofrect definition for a gene?

  The diagram shows a pair of homologous c,ml+g rg+qw-iz p t)5bhromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specuf;e+ ne 2jrbs1w;ko :ific trait, were crossed in an experiment. Which row shows the expectw2nbe jkuo+e :r;f1s;ed phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causef6 vd9yt pg0)ys individual hairs to have a banded pattern. tvd69p)fg 0yy The 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 in9h9f)8 imj 7x3i 9tifkm s;ow:e5xha hdividual pea plants was either round or wrinkled. The results of an eemh93at f89wh x xji h7k5;oi9i s:m)fxperimental 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 (Drosophila melanogaster) / +zhlia)yi98.fsq uf9wi- oj have 8 chromosomes. How many c99i)yfi woa ji hq.+-ul/z8sfhromosomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologous chr2.cr0 hmw,0assqz sr:l3rds ,omosome pairs occur?

The majority of the genes in thecabm1u ,ihw f;* 6ysui28xkk1 human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one k*6 fw,icmi; ysa1x b2h8 k1uurepresentation 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 defi zhj;g:k9 56op6x+q8agqw wvpnition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus n1o er4bwnss5t y35vg ( wf*he3orvegicus). Which arrow iotne34 egwf s(ys5v*35rhw 1bs pointing to a pair of autosomes?

  Mendel observed that there are two possible variations +(62lgrq aszv4jb2v8 kci jp kyu7-q)of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purpsvai842-qp+u j7 )qygkr z2(6jkcb lvle flowers to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the faw7 ;45x+iy9cnufsxfqphw5) 4r mcb/ .q9 xbarequency of birth weight of children born in London in 1991. b7 x )/c4p9rxhafy fsu qni54+5;a.w9wbmcxq

  Which of these traits is an example of continuous vaw98o gxrf4t; sriation?

  Which row correctly describes diploid and hapl/obbo:y,k 4xalezv 88qkx.3l oid cells in humans?

  The following table showso2fgdt/ r ez71 the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia wk : tykoqtgnjx( x0 ))7).piyis 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 had a child with blood type O. Whbo(bgi 1 q*oz/at are the possible genotypez*/(iqbgob 1o s of the biological father?

  Which row shows the correct annotation of the alleles f00k akrk7 *vx o:o) jtjwfj,wxio.1i+or blood groups?

  Which of these statements are tr-l5e +cloc m-bd i66kkwzz78que 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 sprea zs9, 7ps(fgpze +sx4 2ofqwh9yym.9 nd of malaria across the continent of Ap(o2qgn y yfmsf. +9hx 97wzs9ez sp,4frica.


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), f3wm-:l /z6pa xshw l;9/qdinlur colour is determined by a number of genes. Brown colour (B) is dmwq:p x9 snwali-ldl/6h3; /z ominant 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 linked and unl(r2ktsq +fnh3inked genes.

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

Sickle cell anaemia is caused by thfho3g1 c:hviy6 9h*ei e 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 cros: otx7vjv7b9su0p,wc s between a male cat that is homozygous for brown, long hair and a female cat that has black, shtp0c7,:s j7wuvov bx9ort hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacu ++u.nv.,fe 6qlcoa8k7 bbzt8vet :ty m officinale), the allele for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over shor+o:qn86cft7 .vau v.t,eb kzt 8e yb+lt 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 (L9.gdcm)pg h+l onr /(d) is dominant to short hair (l), and curly hair (C) is dominanp rl )hn+cgd9ogd/. (mt to straight hair (c). A test cross was carried out between 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 condition shown in the peeuqdhfjq :2g 54q +sf,digree chart bel,qfgds + 2e4jhqu:qf5ow?

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

  Which of these statements about genetic disorders /g m8vl 7bni2x(,e( k npte*ghis/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 distribuyet4m v)zm+60 adq5lstion.

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 sho.verbf*a cw-sq;92i ywn in the pedigree chart is X-linked recessive and not autoso*ybfa 2-.qi;wsr9cev mal recessive?

  Different species of living organisms2tkxze a/hg*h8t q1 81yen4bt have different numbers of genes characteristic to them. The table shows the estimated n 8 eq8t2hk1/ a*4zgytbtxhe1number 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 2o ay9o ;;yh0j.wic09ly(n okvdxv )l pea plants, including flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rov2l009h.owi v(dlx) cayj ;9ky;noy ules of Mendelian genetics, which of these statements was correct?

  A biological male with hemophilia and a biolo+u iii- foo 6saa139cngical female without hemophilia have a daughter without hemoci+f9 ooia31sn i- ua6philia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower pla i 3-ra3basz i.75yevxnts (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 was 7y zbava3rxi7.i5 se3- .82. The calculated value for the chi-squared test was 10.05; what does this indicate?

1.Explain how parents with blood type A andplv4/nqp fx39g-b n; 1 sml(da blood type B can have a child with blood typqnl3dbp n (1-4 pms;f vagx9l/e O.

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

3.Explain the role of inheritance in genetic diseases.