Practical 3 - BRCA1 Gene Flashcards
(20 cards)
What is BRCA1?
A human tumor suppressor gene that plays a role in DNA repair and regulation of the cell cycle.
BRCA1 stands for breast cancer associated gene 1.
What role does BRCA1 play in the cell cycle?
It plays a role in DNA repair and regulation of the cell cycle, affecting cell cycle checkpoints.
Key checkpoints include G1/S, G2/M, and M.
What is the consequence of mutations in the BRCA1 gene?
Increased risk of breast and ovarian cancer in females and breast and prostate cancer in males.
Mutations can affect cell cycle checkpoints.
What percentage of breast cancers are familial?
About 10%.
Familial breast cancers indicate a predisposition due to inherited mutations.
What is the probability of developing breast cancer for individuals who inherit one mutated allele of BRCA1?
Approximately 50-80%.
The risk increases if a mutation occurs in the other BRCA1 allele.
What is the process of transcription?
DNA → mRNA
Transcription involves the substitution of T’s by U’s and RNA nucleotides linked by RNA polymerase.
What is the process of translation?
mRNA → protein
Translation converts the sequence of mRNA into a sequence of amino acids, forming a protein.
What is the start codon?
AUG
The start codon signals the beginning of translation.
What are stop codons?
UAA, UAG, UGA
Stop codons signal the termination of translation.
What is a nonsense mutation?
One base pair change re-codes a stop codon and shortens the polypeptide
This type of mutation can lead to premature termination of protein synthesis.
What is a silent mutation?
One base pair change that does not alter the amino acid sequence
Silent mutations occur without affecting the protein produced.
What is a missense mutation?
Base pair change that leads to a change in amino acid
This type of mutation can result in a different protein structure and function.
Frameshift mutation
Base pair is added or deleted = it changes the “reading frame” codon
What are Frameshift Mutations?
Frameshift Mutations involve the addition or deletion of one or more base pairs, changing the reading frame of codons.
What does ‘Indels’ refer to?
Indels refer to insertions or deletions of base pairs in DNA.
What is the consequence of a frameshift mutation?
It alters the reading frame, which can change all subsequent codons.
What happens in a deletion frameshift mutation?
In a deletion frameshift mutation, one base pair is deleted, shifting the reading frame.
What happens in an insertion frameshift mutation?
In an insertion frameshift mutation, one base pair is added, shifting the reading frame.
What is the result of a frameshift caused by deleting the first base pair in AUG GCC TGC?
AUG GC- TGC
