A man and a woman have a daughter and a son. Their daug:0e tre+yqg zhd+jx4k (d5w i+o6k;mlhter has normal vision, but their son is colourblind. Which one of these genotypes could be correct for th4klidrhq0ed++jo(mey;5z t+x 6 k :gwe biological mother?

  Which diagram shows the sex chromosomes of a somatic cely5,) n milg;zfv h*n4el in a human male?

  There are two alleles for flower 7f gu-:ceycrf5 yk74hcolour in snapdragons. 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 l:fc feu4ryk7 yh 7-gc5ikely explanation for this observation?

  Which keyword is matched to the correct definitionaxghmy ptf16 m- fe; 9+om)mt;?

  Which of these statements is a correct de //5q1rx;s uezazk ia-finition for a gene?

  The diagram shows a pair of homol karce i -qal0,+yvn )+l4ia;nogous chromosomes.

How many loci are shown?

  Two individuals, heterozygoujv3xof3g2o/8 /yi eits for a specific trait, were crossed in an experiment. Which row shows the expe8/ei o/xiy vto32j g3fcted phenotypic ratios of the offspring resulting from this cross?

  In some animals, the agouti allele cause7jc d zqv5v33es individual hairs to have a banded pattern. The non-agouti allele causes hairs to be a single colour. Individualsjvq5vd z73e c3 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 i2t+tc jjcd)-bjfn2 u3 n individual pea plants was either round or wrinkled. The results of an experimental cross yijt+ 3-2djtcf2ujc)n b elded 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 chromoctjs05z e1mj20ztigi8 4g.ptksjz2* somes. How many chromosomes are in a fertilisz4i 0s8pz1tjz0jkg 5 mcigj2e*2 .ttsed oocyte of a fruit fly?

  When does the random orientation cx64ga 40fmk9 h-b,i-plu vhwof homologous chromosome pairs occur?

The majority of the genegffj/.,n3i o qj xpzj0p89n o(s in the human genome have already been mapped, meaning the exact locations of the genes on chromosomes are known. The diagram below shows one representation of xp3opg9 /0i,jzn8 nqojf .fj (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 l a)so4cu;pm-pl 2va:linked genes?

  The diagram shows a eu:-bwaap ix;s hq))buyw,)+karyogram of a brown male rat (Rattus norvegicus). Which arrow yi;u-eau+ )s : w)b,hpb)wqxa is pointing to a pair of autosomes?

  Mendel observed that there are two possible variatirg5g iy8/dm6 rons of flower colour in pea plants, purple and white. After a genetic cross, the ratio of plants with purple flower grdi6m5 rg/8ys to white flowers is 1:1. What were the genotypes of the parents?

  The graph shows the frequency of bir4so-f r3e.gy60ccpr 93cb gva:sc 3cfth weight of children born in London in 1991. c43c0 e3gy :rs r-cca9o 3ffscpbg6.v

  Which of these traits is an o49gumdkbze0:m 4doje, es2b/e;n/a example of continuous variation?

  Which row correctly describes diploid and haploid ce fl3qrt.r,;o)sa syx5lls in humans?

  The following table shows the diploid ckzm q *u25c29yorny ;khromosome number of a range of species.

Which of these statements is correct?

  Sickle cell anaemia is cause;t .gnjx c*ax(i90d qh ka+2sdd 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 tyg xxsm-+gf/s3t(r h txjpxfc,7 x5,c99*qivupe A had a child with blood type O. What are the possible gu t*xq+c9pjr-t /5(xfgshx ,xf97vicxsm3, genotypes of the biological father?

  Which row shows the correct annotation of the alleles for blocg. lp)r5k1y8p01 k chll e6kcod groups?

  Which of these statements are trm ln/71 y6a9i 9t tgstobw29tfue 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 incidencej,4kh2g4e y u29lcdms l3 fde: of sickle cell anaemia and the spread of malaria across the continent of Afr ge4hfudle3l: 4ykj2sm dc29,ica.


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 by a number of+5atz 8-i:ohqnq j3z a genes. Brown colo:z zqtq+n8i h-a3a5jour (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 linked and unlinked gmj)af m)m: ;nnfc66acenes.

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

Sickle cell anaemia is caused by thlj cmc::wd.e6sa 3 7eie 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 homo8voedgazi)g9jq:i5 (t,7 qn xzygous for brown, g:v5 87nei oitdzg9xa,)q (qjlong hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

  In dandelions (Taraxacum officinale), the alleleg5b-c3y n1e3b l9pzrduo/z y7 for diamond-shaped seeds (D) is dominant over oval-shaped seeds (d) and the allele for long seeds (L) is dominant over short sezpzg ycy 7/u 9db ebor-31nl53eds (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 stnn9l2cev(3e-+ fmlhp g:sh/ hort hair (l), and curly hair (C) is dominant to straight hair (c). A test cross was carried out between male heterozygous long, curly-h-p(cv+:9htn s/ge3fnm2 h l leaired 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 conditiop6g,e t5/w y04z sjnv6tya*vln shown in the pedigree chart b065vt4v , / wn6zylpeat*sygjelow?

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

  Which of these statements about genetic disorders is/are correct?j7ivg; bdb.jyl9,j 0:qvbr:t

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 emb2jr307e hr53.v: m vfvfkmnormal distribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  What suggests that the in.v 464dsl6 xyk89dl6 h wjen;j7snqkdheritance of the disorder shown in the pedigree chart is X-linked recessive and not autosomalwl6 6vydkk ; q9j7xs.8edn h64nslj d4 recessive?

  Different species of living organisms have different numbers of genes charactec ;y2mj;qoqhm1/w /3w7pe dmuu6kgl ,/*kik rristim kr,6kw/lmw;m; p//kjyqg3 hi eu 2o1cd *q7uc to 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, includinett7xdl 37ys;mfe3rw8 s ,+ar 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 yw3+f7 r d38tsreals,tx m;e7these statements was correct?

  A biological male wixyt8w r y6()j ljej 87dpc34pgth hemophilia and a biological female without hemophilia have a daughter wi d6t7p4ylj)8rx g8jw3yc(je pthout hemophilia. What are the possible genotypes of the daughter?

  A dihybrid cross was carried out between twyixuk498+ ic do 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 the 0.05 significance level was 7.82. The calculated value for the chi-squared te+i4iuxk 9yd 8cst was 10.05; what does this indicate?

1.Explain how parents with blood type A ann l8mo 3ggc72lac5* old blood type B can have a child with blood type O*a 3o2 molgcl7 g5ncl8.

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

3.Explain the role of inheritance in genetic diseases.