A man and a woman have a daughter and a son. Their dh h1f0/x3 qpusaughter has normal vision, but their son is colourblind. Whi phqu30x/hs f1ch one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somatic cell in a human male?;selyq,vli6 )

  There are two alleles for flo, g2k6snuy.itox /vfedb c1.k- qp j+:wer colour in snapdragons. However, the result of a cross between two heterozygous plants yielded offspring with three different observed phenotypes, red, white and pink flown bguvxpq6/- ijsf k+kc, ..2:ye1od ters. Which is the most likely explanation for this observation?

  Which keyword is matc 81jz exfqr:, wls;se7xm(;hzhed to the correct definition?

  Which of these statements is ap / )dmhn*jma;p0p qv7 correct definition for a gene?

  The diagram shows a pair of homologous chrd(muwi yl*3 8eomosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, wer nh8(xrvb-ad8 dr 19kme crossed in an experiment. Which row shows the expected phen (vbnmdxdrk r8a8 91h-otypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a ba7g l,+ imtcja9d: :xj+ )hcqzinded pattern. The non-agouti allele causes)j,7+q axld9:jh:cmz+gi cit 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 e m vy)41 )0hwgrpcfmnzbgg9+)ither round or wrinkled. The result9bg0))hy gz f)4pcnrwgmm+ 1vs 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 (Drosop.eve smtlt3 w(23 e*jshila melanogaster) have 8 chromosomes. How many chromos32.ls 3j(wte etms* veomes are in a fertilised oocyte of a fruit fly?

  When does the random orie c7ziu;, sn:clu ja)9jntation of homologous chromosome pairs occur?

The majority of the genes in totq*m5: rxc7 dhe human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram botdm:5rq x7c*elow 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 definitidy7k hq yk;( s5or-i)y(:blyg on of linked genes?

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus). 3 2cn n-,gvxofWhich arrow is poino 2g fn-vxc3,nting to a pair of autosomes?

  Mendel observed that there are twdnd2,9f c)ms no possible variations of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to white flowers is c)n,d9d s2fn m1:1. What were the genotypes of the parents?

  The graph shows the frequency5f)f 0eds u,pe of birth weight of children born in London in 1991. edps , f50efu)

  Which of these traits dbp5* (p.c dtgis an example of continuous variation?

  Which row correctly describes diploid and haploid cells in huma k6khwn, tz+gh z2 cx5lpk)( 8zj-xua)ns?

  The following table sh m2zy p0/xpz9tows the diploid chromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is caused by a recessive ajyhi h ,r:2 8cej6qcm+ kfgnlq6e/d(/w.k oh7llele (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 bl:b53 ;5v1r ldmxlbfnuood type A had a child with blood type O. What are the possible genotypes of the biologicaf:3m bur ;ldxnlb51v5 l father?

  Which row shows the correct annotation of the alleles for blood :7wsyym7( h gzg/e5owgroups?

  Which of these statements ,l ;w-+fe8a vaqfd: 6z1x, p hl awr98zly.wefare 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 cexgm 66h3wy d.tll anaemia and the spread of malaria across the contingwx6y6t.hdm 3 ent 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 +jw te* 05xiwt:iel:pnewc *7by a number of genes. Brown coloutw5lp:j *+0nwi *cex:7 ew eitr (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 link j rcoq/;0 is5corh.r3ed and unlinked genes.

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

Sickle cell anaemia is caused by the amg0oe fu2f4d5rs8 pt-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 crosw r3,z4ubywm.s between a male cat that is homozygous for brown, long hair and a female catw3. buy,4 wrmz that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamos c,xdi9-m1 ibuzk,:ot 78re wnd-shaped seeds (D) is dominant over oval-shaped seeds (d) ,iwm,u7 z- dir c:1otsx8e9k band the allele for long 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), ,wdgkg,y/n +m(f t*ualong 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+*akg fgy/t,nw ,d um(-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; 7cahua4:(f v6.jhkefhs ku7 the pedigree chart belovu4:f ujk 6h;e (hk7sha .c7faw?

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

  Which of these statements about genetic disbz3zh9m6) ww/wy8tga/d kdt+ orders 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 d/fdl.7 pyyjatl .kb/ n)0zi f9istribution.

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 thj :wrqf 2tmv/qd* go8:e disorder shown in the pedigree chart is8qgjt :v2rq*m/od fw: X-linked recessive and not autosomal recessive?

  Different species of lz e.tm9hs srevw*ym- 3*dfuq)ir +. 3eiving organisms have different numbers of genes characteristic ti3e3f.e-rr .vwqzs +mud*syme)th *9o them. 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, including flower colour.fiympadn)p..z 7b(1t If the pea plants Mz. n1yd7it pf). pbam(endel 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 wv3s+j;a *ykqx/* 41zr4z j gy xgcd lf4lxy;r-ithout hemophilia have a daughter without hemophxs-4 qyylfjz a 4dcx/z+3y1xlv* ;; k*4jrggrilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianyek vs)x(778 g;kxhu pthus annuus) to see if the genes for seed number and seed shape are linked. e()gusvkkp;x7yh87 xThe 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 type A and blood typeqq)9oh./ )isxu 8r i3bah)drm B can have a child with blood typq m9r )hro /d.sabiq)8 hi3)xue O.

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

3.Explain the role of inheritance in genetic diseases.