Biological Sciences - Mutation and DNA Repair

What is a mutation?

A mutation is a permanent alteration in the DNA sequence that makes up a gene, which can lead to changes in the function or expression of that gene.

What is a point mutation?

A point mutation is a change in a single nucleotide base pair in the DNA sequence, which can result in a different amino acid being incorporated into a protein, potentially altering its function.

What is a base mutation?

That involves the substitution, insertion, or deletion of one or more nucleotide bases in the DNA sequence, affecting gene expression or protein function.

What is an insertion?

An insertion is a type of mutation where one or more nucleotide bases are added into the DNA sequence, potentially altering the reading frame and affecting protein synthesis.

What is a deletion?

A deletion is a type of mutation where one or more nucleotide bases are removed from the DNA sequence, which can disrupt the reading frame and lead to significant changes in protein synthesis.

What is a frameshift mutation?

A type of mutation caused by insertions or deletions of nucleotide bases that shift the reading frame of the genetic code, often resulting in altered or nonfunctional proteins.

What is a silent mutation?

A type of mutation that does not affect the amino acid sequence of a protein, often due to redundancy in the genetic code. Silent mutations typically occur when a change in the DNA sequence does not alter the resulting protein's function.

What is a missense mutation?

A type of mutation where a single nucleotide change results in the substitution of one amino acid for another in the protein sequence, potentially altering the protein's function.

What is a nonsense mutation?

A type of mutation that introduces a premature stop codon in the protein sequence, leading to truncated proteins that are usually nonfunctional.

Can mutations also occur in regions that do not code for a protein?

Yes, mutations can occur in non-coding regions of DNA, which may affect regulatory elements and gene expression without altering protein sequences.

What happens if a mutation occurs in the promoter region?

It can disrupt the binding of RNA polymerase, leading to decrease or an increase in the rate of transcription of the associated gene and potentially affecting gene expression.

Can mutations also occur in regulatory segments of DNA?

Yes, mutations in regulatory segments can affect gene expression and the binding of transcription factors. These mutations can lead to enhanced or reduced transcription of target genes.

Can mutations in germ cells be passed to offspring?

Yes, mutations in germ cells can be inherited by offspring, potentially leading to genetic disorders or variations in traits.

What is a germ cell?

A reproductive cell that gives rise to gametes, such as sperm and eggs, and carries genetic information to the next generation.

What is a somatic cell?

A non-reproductive cell that forms the body of an organism and does not contribute to the genetic material passed to offspring.

Can somatic cells be passed onto offspring?

No, somatic cells cannot be passed onto offspring as they do not contribute to gametes.

What is a base excision repair?

A DNA repair mechanism that removes and replaces damaged or mismatched bases in the DNA sequence, maintaining genomic integrity.

What is a nucleotide excision repair?

A DNA repair process that removes bulky DNA lesions, such as those caused by UV light, by excising a short single-stranded DNA segment containing the damage.