Class 12 Biology · Chapter 7 · Test 5
Mutations and Genetic Disorders
37 MCQs
37 questions · 30 min · 37 marks
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Sample questions
The first 5 of 37. Try each one, then tap to see the answer.
Question 1
Ultraviolet radiation can cause mutations by:
- AMaking double covalent bonds between adjacent pyrimidine bases
- BBreaking phosphodiester bonds in DNA strands
- CAdding nucleotides in DNA
- DSubstituting nucleotides in DNA
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Answer: A
UV causes bonding between adjacent C and T which can block replication.
Question 2
Phenylketonuria is a genetic disorder with a defect in the metabolism of:
- AVitamin
- BGlucose
- CAmino acid
- DLipid
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Answer: C
The enzyme PAH that converts phenylalanine to tyrosine is defective.
Question 3
The condition sickle cell anaemia is due to:
- ADeletion type point mutation
- BSubstitution type point mutation
- CInsertion type point mutation
- DChromosomal rearrangement
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Answer: B
T is substituted by A in the β-globin gene.
Question 4
A change in the content of the genetic message is called a:
- AMutation
- BReplication
- CTranslation
- DTransformation
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Answer: A
Mutations may be small or large.
Question 5
Mutations caused by external factors such as radiation are called:
- ANatural mutations
- BInduced mutations
- CSilent mutations
- DSpontaneous mutations
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Answer: B
Natural mutations occur spontaneously.
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