A man and a woman have a daughter and a son. Their daugh zm9 skgel(fx3x g3:v2ter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for th2(9f kglez: x3 g3svxme biological mother?

  Which diagram shows the sex chromosomes of a som8x h56l kd;7fsndmse/atic cell in a human male?

  There are two alleles for flower 94 usb8dwl4fwy5j 8r9( zloek colour in snapdragons. However, the result of a cross between two heterozygo959z dlywe8 r sfo8 4kbjl4uw(us 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 4fov(p e mcps,qk,-/n definition?

  Which of these statements is a correct definipkmxku.- j3i ;tion for a gene?

  The diagram shows a pair of homologous 42us,pqq m- f n:l+pbpchromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, were crossed in an experi lvx. d(9n,wmce.p: ye,4q xjcmentjy: ecqmxle4x c.w,9p v(d.,n. Which row shows the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele l6a ug5 8lrhb6causes individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs with ar5l8b 6lh6 uga 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 smhrnf ,nh4 tn*;a a;2uhape in individual pea plants was either round or wrinkled. The results of an experimental cross yra fhuhnm 24t *na;,n;ielded 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) have 8 chd ;vqxn:kbkn.hq+r/ sk)qa9 .romosomes. How many chromosomes are : x.9kb+k;) qqr as.kh/dvnnqin a fertilised oocyte of a fruit fly?

  When does the random orientatio6ifdb2:1: l2lm; ivf1z ll m;wjdus q,n of homologous chromosome pairs occur?

The majority of the genes in the human genom))/x 8jvzm sjwbx02zce have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below zjxs jc zb)v0m)w8/2xshows 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 kmfpo223(dt/m k3 ssohss8il b)n (4l definition of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norv( 31l kvnwp0svegicus). Which arrow is pointing to a p nvk (v310lwpsair of autosomes?

  Mendel observed that there are two possible varia1nv nw e 7ee:xwi 156cnbs8io-tions of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is 1:1. What were the genotys n-en6 i5e1w1xv 78nbcow:eipes of the parents?

  The graph shows the frequency of bir .i25mbke*vu+b -jljzth weight of children born in London in 1991j u e*ibkmbz-2. jl5+v.

  Which of these traits is an exampld; sa 1-* csw3xfampnp0,n- t9n k/zmle of continuous variation?

  Which row correctly .;dij:w3 o snfdescribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome numb seqc)9sr3ygkjj; ),0kau h 3ger of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive allel74klwxgzk5cx t:h10qin m;ls 76w/ fue (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 tr(t*m bjtln.8i (bzdd19goh - ype O. What are the possible ge(h (z .9i 1gltmrtbdd*-n8 jobnotypes of the biological father?

  Which row shows the correct annotation of the allesioqnen8q- bow , l 9kd+n.pg0*+6 froles for blood groups?

  Which of these statements are true o1htygggm6iem.8 4 l/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 v e2xf- 8m)vyvof sickle cell anaemia and the spread of malaria across the conti my28 -vxv)fvenent 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 dx jan*2yqr bxh84 lc.,etermined by a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is dchbljyq ,8r2x4na .x* ominant 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 lr7cmmdc.(3dw v7 d*rand unlinked genes.

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

Sickle cell anaemia ilh- ( g)h/+yjwup-o bts caused 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 between4aanz7jrv f;6b8wa1 v ,mwkl3 a male cat that is homozygous for brown, long hair and a female cat 4zj,;av7 m wr3a6alfn1 bvkw8that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamon rrkb o7, 5,3lzjia-hgd-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short s5 agz-kj ibl,,hror37 eeds (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 sho8)k zlzu6/gu ert hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous long, curly-hg)uz uez6/lk8aired 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 pe*e6 uqg) n9vc3nclx/xdigree chart below?9uvl )n*xe gcq/n63cx

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

  Which of these statements about .r.f x2n yftc:ko py67genetic 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 distributims5h, lh8 /t ypw*r7tlon.

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 pedigree chart x-tbq c(lo8+3y9rz+zn l*rvcis X-linkedytqcr(o v x8*-br ++ zczl39nl recessive and not autosomal recessive?

  Different species of living organisms have different numbers of gene ih,*z*wx eems6(j hh0s characteristic to them.*iwxe h j6hh0(e mz*,s The table shows 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, includinuyecer.8kmhx8b: t2 (g flower colour. If the pea plants Mendel was studying can only be white or purple and follow the rules of Mendelian genetics, which of these statements h2x.(t : ycke er8mb8uwas correct?

  A biological male with hemophilia and a biological female witho/mh vi) lq+7gkz)vzc:ut hemophilia have a daughter without hemophilia. W ch+ zz/:v7q)lgik)vm hat are the possible genotypes of the daughter?

  A dihybrid cross was carried out betweenx38- :* tcmwnpr:4 ;ry bvnkke two 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 therbk;cm vtywpenx-:r 4 n8 k3:* 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 type A and blood type B can have a child with jueqgbt+ k9m u a8117nbln ub18 mu jq1g+7ate9kood type O.

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

3.Explain the role of inheritance in genetic diseases.