Lecture 11: Mutations and Cancer Flashcards
Describe how DNA mutations can alter gene products.
DNA mutations can lead to changes in the sequence of nucleotides, which may affect the structure and function of proteins produced by genes. These mutations can be classified as germline, affecting future generations, or somatic, impacting only the individual. Depending on the type of mutation—substitutions, insertions, or deletions—the effects can range from no change (silent mutations) to significant alterations in protein function, potentially leading to diseases such as cancer.
What are DNA mutations?
DNA mutations are changes in the sequence of nucleotides that may affect the structure and function of proteins produced by genes.
What are the two main types of DNA mutations?
DNA mutations can be classified as germline (affecting future generations) or somatic (impacting only the individual).
What are the three types of DNA mutations based on nucleotide changes?
Substitutions, insertions, and deletions.
What are the possible effects of DNA mutations?
Effects can range from no change (silent mutations) to significant alterations in protein function, potentially leading to diseases such as cancer.
Why do mutations “can” affect protein function and not “always”?
Altered DNA sequences can have major, minor, no, or even positive effects on resulting protein function
What are germline mutations?
Germline mutations are genetic alterations that are passed on to future progeny.
What are somatic mutations?
Somatic mutations occur during cell division and affect only the individual, leading to local effects such as tumors.
What are large-scale alterations in DNA?
Large-scale alterations refer to chromosomal rearrangements that form incorrect tetrads can affect multiple genes, called translocations.
What are small-scale alterations in DNA?
Small-scale alterations involve changes to one or a few nucleotides in the DNA sequence.
What are substitutions in DNA mutations?
Substitutions are mutations where one base is replaced by another, which can have minimal or major effects on protein function.
What are insertions and deletions (indels) in DNA mutations?
Insertions and deletions can have major effects if they occur within a coding sequence, potentially causing a frameshift.
What is a silent mutation?
A silent mutation is a substitution where the codon changes (e.g., GGC to GGU) but still codes for the same amino acid (Glycine), resulting in no effect on the protein.
What is a missense mutation?
A missense mutation is a substitution that changes one amino acid to another (e.g., GGC to AGC, changing Gly to Ser), and the effect depends on the role of the residue.
Which of the following alterations to the coding region of an mRNA transcript is MOST LIKELY to have an impact on the function of the resulting protein?
A single base indel near the middle of the mRNA.
