Mutations Flashcards
(13 cards)
What are the two main causes of mutations?
Errors in machinery (spontaneous) and environmental factors (induced)
Environmental factors can include radiation, viruses, and chemicals.
What are mutagenic agents?
Agents that cause mutations, including:
* Radiation (UV or X-rays)
* Viruses
* Chemicals
Mutagenic agents can lead to changes in DNA sequences.
What are point mutations?
Mutations at one specific base pair in the genome
Point mutations can significantly affect gene expression and protein function.
Define substitutions in the context of mutations.
Replacement of one base pair in a DNA sequence by another base
Substitutions can be silent, missense, or nonsense.
What is a silent substitution?
A substitution that does not result in a change in the amino acid coded and does not cause phenotypic change
May occur in an intron that is removed or be a redundant switch in base pair.
What is a missense substitution?
A substitution that changes one base pair sequence in a codon, resulting in a substitution of one amino acid in a polypeptide sequence
Example: sickle cell anemia.
What is a nonsense substitution?
A change in the base pair sequencing of a codon that results in a stop codon being inserted where one amino acid should be
This usually results in only part of the protein being produced, which is likely digested by enzymes.
What are frameshift mutations?
Mutations that cause the reading frame of codons to change
Usually results in different amino acids being incorporated into the polypeptide, caused by deletions or insertions.
True or False: Frameshift mutations can be caused by deletions or insertions.
True
Frameshift mutations alter the reading frame, potentially leading to significant changes in the resulting protein.
What is translocation in the context of chromosomal mutations?
Involves two chromosomes that aren’t homologous, where part of one chromosome is transferred to another chromosome
Translocation can lead to genetic disorders or cancers if it disrupts important genes.
What is deletion in chromosomal mutations?
A piece of the chromosome is lost
Deletion can result in loss of function for genes located in the deleted region.
What happens during inversion in chromosomal mutations?
A chromosome segment breaks off, flips around backwards, and reattaches
Inversions can disrupt gene function and lead to various genetic disorders.
What is duplication in chromosomal mutations?
Occurs when a gene sequence is replaced
Duplications can lead to gene dosage effects and contribute to evolutionary processes.
