12 Biology Genetics exam Practise With Answers

8/13/2019 12 Biology Genetics exam Practise With Answers

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12 BIOLOGY Genetics Exam Practice

Part A:

1. Below are four pedigrees of families in which there are members who have inherited thecondition known as achondroplasia, a type of dwarfism. Which of the pedigrees is inconsistentwith inheritance as an autosomal dominant? (Shaded individuals ehibit the trait!.

(a! (b! (c! (d!

". #olour blindness in humans is a se linked recessive trait. $f a woman with normal vision, whosefather was colour blind, marries a man with normal vision, then%a. no sons will be colour blind.b. all of their sons must be colour blind.c. their daughters cannot be colour blind.d. their daughters will be colour blind.

&. 'he t)*+ molecule which specialises for transfer of the amino acid methionine has theanticodon +#. What codon on the m)*+ codes for methionine?a. +'-b. +-c. '+#d. #+

. 'he genotypic ratio of the /"offspring from a monohybrid cross between a homo0ygousdominant and a homo0ygous recessive parent is%a. &%1b. 1%"%1c. %&%&%1d. %2

3. + certain protein is composed of 1322 amino acids. 'he number of bases in the generesponsible for its synthesis is%a. 1322b. 322

c. &d. 322

4. 5aemophilia is a selinked recessive gene in humans. + father and son are bothhaemophiliacs, but the mother is normal. 'he mothers genotype is%a. 6h7b. 6565

c. 656h

d. 6h6h

8. + man has blood type B. 9ne of his parents had blood type 9. 'he man marries a woman withblood type +B. 'he theoretical percentage of their children with type B blood is%

a. 2:b. "3:c. 32:d. 83:

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;. +n anticodon is a triplet code on%a. m)*+ that codes for a particular amino acid.b. t)*+ that codes for a particular amino acid.c. t)*+ that binds to a complement on m)*+.d. r)*+ that assists in binding amino acids together.

. Which of the following does not constitute a part of


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13. )espond 'rue or /alse to the following statements.a. 'ranslation occurs within the nucleus.b. + change, deleterious or beneficial, in the genetic make up of an individual is called a

mutagen.c. =eiosis only occurs in somatic cells and is responsible for the growth of the individual.d. 'he replication of


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"1. $n humans, each chromosome carries many genes. Some of the genes on chromosome number1 (an autosome! are%

Gene Function Alleles

Shape of red blood cells @ @lliptically shaped cellse *ormally shaped cells

)hesus blood group < )hesus positived )hesus negative

>roduction of amylase + +mylase produced

a *o amylase produced

'he number 1 chromosome make up of the parents who had a large family was

@ e e e

< < d d

+ a a a

=other /ather

)espond Trueor Falseto each of the following statements. se the information presentedabove.$t would be reasonable to claim that%a. some of the children would have elliptically shaped red blood cells.b. some of the children would be )hesus negative.c. some of the children would produce amylase.d. the mother is hetero0ygous at two of the gene loci shown.e. the mother produces amylase half of the time.f. the father is )hesus positive.


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"". $n rabbits, one gene controlling fur colour has the allelic forms, dark (


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"&. $n mice, there is a mutation which gives hair a yellow colour. When a mutant (yellow! mouse wascrossed with a normal mouse, about half the offspring were yellow, and half normal. *one ofthese normal mice produced any yellow offspring when interbred. 'he yellow offspring producednormal and yellow offspring in roughly eual numbers when mated with normal mice, but whenintercrossed (yellow mated with yellow! about one third of the offspring were normal and twothirds yellow.7ellow females mated to yellow males tend to have somewhat smaller litters than yellow females

mated to normal males.

Suggest an hypothesis to account for these observations, and eplain your reasoning.

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Year 12 Biology Genetics Exam Practise ANSWERSF1. < F4. #F". # F8. #F&. B F;. #F. B F. BF3. < F12. #

F11. genotype + "

allele B 4homo0ygous # &gene < 1phenotype @ 3gamete / ;

F1". 'ranscription and 'ranslation

F1&. a! +- -#+ +-b! &

F1. G 9ne triplet (codon! euals one amino acidG Some amino acids are coded for by by several triplets (codons! (more than one correspondingcodon!. Stop codons also eist that do not code for an amino acid.

F13. a! /alseb! /alsec! /alsed! 'rue

F14. a!

) W

) )) )W

W W) WW

b!1H ("3:! chance of a red calf

F18. a! 7es G a male child has an 6 and 7 chromosomeG for a male to be born, the male =S' give the 7 chromosomeG 'herefore, you can also identify a chromosome from mum (6!

b! *9 G a female child has an 6 and an 6 chromosomeG no way of telling who the 6 came from, from a simple karyotype, since one 6 came fromeach parent

F 1;. a! 6b6b (female! G 6B7 (male!

b!

6B 7

6b 6B6b 76b

6b 6B6b 76b

c! 122:, 1, all

F1. Somatic cell not inherited

affect person during their lifetime-erm Iine cell inherited (passed on to future generations!

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F"2. 77 C genotype for yellow pure breeding Since all /1 were yellow therefore7 isyy C genotype for green pure breeding dominant.

7 y

7 77 7y

y 7y yy

*o green seeds means that 7y 7y is not acceptable.

'herefore only other crosses include 77 7y or 7y 77 or 77 77 J J J

F"1.a. 'rue d. 'rueb. /alse e. /alsec. 'rue f. /alse

F"". a. dd

b.

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12 Biology Genetics exam Practise With Answers