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📘 Mutation MCQ Challenge

Question 1
Mutation is defined as

Explanation: Mutation is a sudden, stable and heritable change in genetic material.

Question 2
The ultimate source of genetic variation is

Explanation: Mutations create new alleles.

Question 6
Which amino acid is replaced in sickle cell anaemia?

Explanation: Normal haemoglobin contains glutamic acid.

Question 7
Insertion or deletion of a base pair leads to

Explanation: Reading frame changes.

Question 8
Which mutation does NOT change amino acid sequence?

Explanation: Silent mutations code for the same amino acid.

Question 9
Which mutation results in premature stop codon?

Explanation: Nonsense mutations introduce a stop codon, ending protein synthesis early.

Question 10
Chromosomal mutations involve

Explanation: Chromosomal mutations involve structural changes in chromosomes.

Question 11
Loss of a chromosomal segment is called

Explanation: Deletion removes a part of the chromosome.

Question 12
Reversal of a chromosomal segment is

Explanation: Inversion reverses the orientation of a chromosomal segment.

Question 13
Exchange of segments between non-homologous chromosomes is

Explanation: Translocation involves exchange of segments between different chromosomes.

Question 14
Increase in gene dosage occurs due to

Explanation: Duplication produces an extra copy of a gene, increasing gene dosage.

Question 15
Genome mutations involve change in

Explanation: Genome mutations alter the number of chromosomes.

Question 16
Trisomy 21 is an example of

Explanation: Trisomy is a type of aneuploidy involving an extra chromosome.

Question 17
Down syndrome is caused by

Explanation: Down syndrome results from an extra copy of chromosome 21.

Question 18
Turner syndrome has the karyotype

Explanation: Turner syndrome is caused by monosomy of the X chromosome.

Question 19
Klinefelter syndrome shows

Explanation: Klinefelter syndrome occurs due to an extra X chromosome in males.

Question 20
Polyploidy is common in

Explanation: Plants tolerate polyploidy well and it is common among them.

Question 21
Mutations occurring naturally are called

Explanation: Spontaneous mutations occur without external agents.

Question 22
Mutations caused by mutagens are

Explanation: External mutagens induce mutations.

Question 23
UV radiation causes

Explanation: UV radiation induces thymine–thymine dimers in DNA.

Question 24
Which is a chemical mutagen?

Explanation: Nitrous acid alters base pairing by deamination.

Question 25
Viruses can cause mutation by

Explanation: Some viruses act as biological mutagens via transposition.

Question 26
Somatic mutations

Explanation: Somatic mutations affect body cells only.

Question 27
Germinal mutations

Explanation: Germ cell mutations are inherited and drive evolution.

Question 28
Cancer is often caused by

Explanation: Cancer results from accumulation of somatic mutations.

Question 29
Which mutation is most harmful?

Explanation: Frameshift mutations alter the entire reading frame.

Question 30
Which mutation does not affect phenotype?

Explanation: Neutral mutations produce no observable effect.

Question 31
Mutations help organisms by

Explanation: Mutations generate genetic variation essential for adaptation.

Question 32
Which mutation changes one amino acid?

Explanation: Missense mutation replaces one amino acid with another.

Question 33
Deamination affects which base?

Explanation: Cytosine deaminates to uracil.

Question 34
Which is NOT a chromosomal mutation?

Explanation: Point mutation occurs at gene level, not chromosome structure.

Question 35
Polyploid wheat is an example of

Explanation: Polyploidy involves change in chromosome sets.

Question 36
Frameshift mutation occurs due to

Explanation: Addition or loss of nucleotides shifts the reading frame.

Question 37
Mutation producing stop codon early is

Explanation: Nonsense mutation introduces a premature stop codon.

Question 38
Aneuploidy arises due to

Explanation: Failure of chromosome separation leads to aneuploidy.

Question 39
Which is a beneficial mutation?

Explanation: Some mutations enhance survival, such as antibiotic resistance.

Question 40
Which mutation affects chromosome number?

Explanation: Aneuploidy involves gain or loss of chromosomes.

Question 41
Mutation rate can be increased by

Explanation: Mutagens increase the frequency of mutations.

Question 42
Which mutation leads to Cri du chat syndrome?

Explanation: Cri du chat syndrome is caused by deletion of the short arm of chromosome 5.

Question 43
Which mutation is least harmful?

Explanation: Silent mutations do not change the amino acid sequence.

Question 44
Transposons cause mutation by

Explanation: Transposons move within the genome, disrupting genes.

Question 45
Mutation is essential for

Explanation: Mutations create variation driving evolution.

Question 46
Mutagens act on

Explanation: Mutagens alter DNA structure or sequence.

Question 47
Which mutation alters phenotype severely?

Explanation: Frameshift mutations disrupt the entire protein sequence.

Question 48
Which disorder is due to point mutation?

Explanation: Sickle cell anaemia results from a single base substitution.

Question 49
Structural chromosome mutations do NOT include

Explanation: Aneuploidy involves chromosome number, not structure.

Question 50
Mutation causing change in codon but same amino acid is

Explanation: Silent mutations do not alter the amino acid sequence.

📊 Result Summary

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