The BRCA1 gene encodes a protein that contains 1,863 amino acids. This protein is involved in DNA repair and regulation of the cell cycle. 1. Define the term “opening reading frame” (ORF). 2. If BRCA1 protein is made up of 1,863 amino acids, how many nucl

1. An open reading frame (ORF) is a sequence of DNA or RNA that encodes a protein and is uninterrupted by stop codons. 2. Since each amino acid is encoded by a sequence of three nucleotides (a codon), the open reading frame for BRCA1 would be 1,863 x 3 = 5,589 nucleotides long. 3. The mature mRNA for BRCA1 may be longer than the ORF because it contains untranslated regions (UTRs) at the beginning and end. These UTRs contain regulatory sequences that are important for controlling gene expression and may also contain functional elements such as binding sites for mRNA stability factors. Additionally, the mRNA may undergo processing such as splicing, which can result in removal of introns and further modification of the sequence. 4. A gene is a sequence of DNA that encodes a functional RNA or protein product. Genes are the basic unit of heredity and are responsible for the traits and characteristics of an organism. They are regulated by various mechanisms that control their expression and can be subject to mutations that alter their function or cause disease.