Mutations and Their Effects

These flashcards cover key concepts about mutations, their types, and their effects on proteins and gene expression.

What are mutations?

Changes from the original form of a DNA strand that can result in different proteins.

What is a point mutation?

A mutation that affects a single nucleotide base in the DNA sequence.

What is a transition mutation?

A point mutation where a purine is substituted for a purine or a pyrimidine for a pyrimidine.

What is a transversion mutation?

A point mutation where a purine is substituted for a pyrimidine or vice versa.

How do point mutations affect proteins?

They can change the amino acid sequence, potentially altering the protein's structure and function.

What is a silent mutation?

A mutation that does not affect the amino acid sequence of the protein.

What is a missense mutation?

A mutation that changes one amino acid in the protein, potentially altering its function.

What is a nonsense mutation?

A mutation that creates a stop codon, leading to premature termination of protein synthesis.

What are insertions and deletions in mutations?

Mutations that add or remove nucleotides, which can cause frame shifts.

What is a frameshift mutation?

A mutation caused by insertions or deletions that alters the reading frame of the genetic code.

What is the effect of a frameshift mutation?

It can change the entire amino acid sequence downstream of the mutation, potentially leading to nonfunctional proteins.

Where do spontaneous mutations commonly occur?

During DNA replication.

What is depurination?

The loss of a purine base (adenine or guanine) from the DNA.

What is deamination?

The loss of an amine group from a nucleotide, often turning cytosine into thymine.

What types of mutations can affect gene function?

Amorphic mutations (loss of function) and neomorphic mutations (gain of function).

What distinguishes somatic mutations from germline mutations?

Somatic mutations occur in non-reproductive cells and are not passed to offspring, while germline mutations occur in gametes and can be inherited.

What happens to the protein if there is a nonsense mutation early in the coding sequence?

It is likely to abrogate the entire protein's function.

What is the importance of understanding transitions and transversions?

They can help in differentiating species and understanding evolutionary relationships.

What is the typical outcome on protein functionality after a missense mutation?

It varies based on the specific amino acid change, which can alter protein function significantly.