Gene Mutation Types Quiz

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Questions and Answers

What is the effect of base substitution in a gene mutation?

Has no effect on the encoded protein (correct)

Adds nucleotide pairs in a gene

Results in loss of nucleotide pairs in a gene

Changes one amino acid to another

Which type of gene mutation involves the addition of nucleotide pairs in a gene?

Base substitution

Base insertion (correct)

Chromosomal mutation

Base deletion

In gene mutation, what is the effect of missense mutation?

Changes one amino acid to another (correct)

Results in loss of nucleotide pairs in a gene

Adds nucleotide pairs in a gene

Has no effect on the encoded protein

Which type of mutation involves the loss of nucleotide pairs in a gene?

Base deletion Signup and view all the answers

What is the term for a mutation that occurs spontaneously without exposure to external factors?

Spontaneous mutation Signup and view all the answers

Which type of mutation involves changes in a single nucleotide pair?

Point mutation Signup and view all the answers

What types of physical agents are mentioned in the text as causes of DNA damage and gene alteration?

UV and gamma rays Signup and view all the answers

How does ethidium bromide cause alterations in DNA?

By creating extra space between DNA bases Signup and view all the answers

What is the effect of base deletion in a gene mutation?

Frameshift mutation Signup and view all the answers

Which mutation results from changes in a single nucleotide pair of a gene?

Point mutation Signup and view all the answers

What is the main characteristic of induced mutations?

They are caused by environmental factors or chemicals Signup and view all the answers

What effect does colchicine have on spindle fiber development?

Prevents homologous chromosome separation Signup and view all the answers

What is the definition of mutation?

A permanent change in the nucleotide sequence of an organism’s DNA Signup and view all the answers

Which type of mutation is characterized by error during DNA replication or recombination?

Point mutation Signup and view all the answers

What is a mutagen?

A chemical or physical agent that interacts with DNA and leads to mutation Signup and view all the answers

Which class of mutation is caused by external factors such as chemical agents?

Induced mutation Signup and view all the answers

What is the outcome of non-disjunction during meiosis?

Production of gametes with abnormal chromosome numbers Signup and view all the answers

Which term refers to a gene that has undergone mutation or an organism carrying a mutated gene?

Mutant Signup and view all the answers

Study Notes

Mutation

Mutation: a permanent change in the nucleotide sequence of an organism's DNA, important as a source of genetic diversity
Types of mutation:
- Spontaneous mutation: occurs due to error during DNA replication or recombination
- Induced mutation: caused by mutagens (chemical or physical agents that interact with DNA)

Classification of Mutations

Two main types of mutations:
- Gene/point mutation: changes in a single nucleotide pair of a gene
- Chromosomal mutation: changes in the number or structure of chromosomes

Gene Mutations

Definition: changes in a single nucleotide pair of a gene
Three types of gene mutations:
- Base substitution: one nucleotide pair is replaced with another (e.g. sickle cell anaemia)
- Base insertion: addition of nucleotide pairs in a gene
- Base deletion: loss of nucleotide pairs in a gene (e.g. thalassaemia)

Effects of Base Substitution

Silent mutation: base substitution has no effect on the encoded protein
Missense mutation: base substitution changes one amino acid to another
Nonsense mutation: base substitution leads to the premature termination of protein synthesis
Frameshift mutation: base insertion or deletion leads to a change in the reading frame of the genetic code