A man and a woman have a daughter and a son. Their daughter has normal vision, b (9jyb oay x- djd,b1(y2dvyv:ut their son is colod-bbov(j9y ,2ajvyd y(1dy :xurblind. Which one of these genotypes could be correct for the biological mother?

  Which diagram shows the sex chromosomes of a somat7q sm2o4jf+id0 na(lf ic cell in a human male?

  There are two alleles for flolpswx5kk f8m 7t1k9 l, ,cegg,wer colour in snapdragons. However, the result of a cross between two heterozygous plants yie,kg klf,m 8pwx5l 9 1gte7s,cklded offspring with three different observed phenotypes, red, white and pink flowers. Which is the most likely explanation for this observation?

  Which keyword is matp* 71v4gxevji2i6/ mksgpd+uched to the correct definition?

  Which of these statements isxz+ld jvn7dew 2+ vx6yuw. 8-a a correct definition for a gene?

  The diagram shows a pair of homologo a qsw9,ep;*kbus chromosomes.

How many loci are shown?

  Two individuals, heterozygous for a specific trait, ce1+f nums zo-++dat9 were crossed in an experiment. Which row shode-+tc mfuo n+z+s91aws the expected phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele causes individual hairs to have a banded qxa+j8hk0zgcysuyo 4 y2 c jplcz/xz62,*;f-pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs with a banded pattern.ac/ jfglzcq ,;zy -*x84op0x yjyczk h226+su

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 eithfd ,x-b b w x+tc32s-9nvcecxp-.dqi9er round or wrinkled. The re f + ecwb,xd- qtx2bpv3c9 isn-9c.d-xsults 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 flp+a.2 fsn7 * lb yvq*tpy v7yi2kx,f.by (Drosophila melanogaster) have 8 chromosomes. How many chromtsl x2bny p7 fbvkv *ayi,72p+q.yf.*osomes are in a fertilised oocyte of a fruit fly?

  When does the random orientation of homologod2cj+*z xw1hxbten 3 /us chromosome pairs occur?

The majority of the genes in the human genome have a* g62 ua6j20 vadqkcutlready been mapped, meaning the d *u0ucqg6j6tvka2a2exact locations of the genes on 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 definition of linked genes?vjg5s vy6m667 wbqof,

  The diagram shows a karyogram of a brown male rat (Rattus norvegicus)brt pqy7.*sll odx2 :,. Which arrowp 2s .,t :*yqoxl7rdlb is pointing to a pair of autosomes?

  Mendel observed that there are two possible variations of flower col.ak yixz*y2 uk(p-ay+our in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flowers to whitexa a*uikp z +-ky2y(y. flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of birth weight 5jxes h7odr8ev q hm)2pz3.2wof children born in London in 1991.m8.3 qphe r5w jz2x)sdhv27oe

  Which of these traits is an example of continuous variationty2uj;( tguu9 ?

  Which row correctly describes diploid and haploid cells in humans? qy4es5:vvdda q;k6n:fffl; 7

  The following table shows the diploid chromosome number of a rankz(p1a2 vdx m hab32*age of species.

Which of these statements is correct?

  Sickle cell anaemia is 9jxc+f 9:4evw3n caorcaused 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. Wham ,ej4*xzx)gvt are the possible genotypes of the biological fathv e)x zmgxj,*4er?

  Which row shows the correct annotatioh)a v6exm)s8xn of the alleles for blood groups?

  Which of these statements are true for al3pamn*)s m/ s-gj1 .s0sorxx lleles?
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 sprek4;elgl vm f4wc p1*3yad of malaria across thel3v *4wkp cyl ;f4gm1e 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 is determined d7*t i.j4so 8ue ejb(rby a number of genes. Brown colour (B) is dominant to sandy colour (b) and an ombre (two tone) colour (P) is domintr 8jo(eb7is*.4j edu ant 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 linkedtj3a*vx0pt k6 and unlinked genes.

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

Sickle cell anaemia is caused by - zh8tm/. k 05pxpwmvuthe 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 homozygous forcnyyu*ex59 f+0op u 3s brown, long hair and a female cat90+ co ux5y*u3eypnfs that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the allele for diamond-shaped seedsoo+d k9m qe-m( (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant ove-9 q+k(emo domr 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.15imh.2mb7eux1 wja e s.kzu (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 hamz e i.wx.1 skeu5hu1j2bm7.eterozygous 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 sh79 j2gjfbyrau.v4 zf9own in the pedigree chart below2ay9 74f 9.zubrfg vjj?

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

  Which of these statements about genetic disorders is/are coeu cl5afpum0n3d8 l3 b n+lo7*rrect?

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 sho2kp6bxz z9l0 ,+f ctoiw 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 inheritancnre+irr qal(1.* v2k pe of the disorder shown in the pedigree chart is X-linked rece 1er.rkiav+ (2 ql*prnssive and not autosomal recessive?

  Different species of living organisms have different numbeaba 2y*opq7f4rvu.g(dw;r:a rs of genes characteristic to them. The table shows the estimated number4 qfaa:yrd (ov* 7;bp.r ug2wa 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 eightgv:9pd b2n klykv4 x4+ characteristics of pea plants, including flower colour. If the pgvpyx4dk4:v 2lk9n+b ea 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 h8sai 9d. :snflks dw rp5o+1;pemophilia have a daughter without hemophilia.n d k5 p i+o189;sssw.lrafp:d What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between two sunflower plants (Helianthus annuuk (c( vd blt2i01v(siaqz4o;js) to see if the genes for seed number akj1ol0v((q s c(;dv2b z4tii 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 type A and blood type B cankdmm8u;a;5/9ej lelqr r2; k 2 x pgo7u)vgw0m have a child with blood type O. wpjm /m oe x;70v9rdg)k5q;r; lgua 8um2lk2e

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

3.Explain the role of inheritance in genetic diseases.