A reading frame is the way in which the nucleotide sequence of DNA or RNA is read during transcription and translation. The genetic code consists of triplet codons, and each codon codes for a specific amino acid. The nucleotide sequence is read in groups of three (codons), and the reading frame determines the order in which codons are read.
When the reading frame is changed, the order in which codons are read is altered, which can have significant effects on protein synthesis. A frameshift mutation occurs when nucleotides are inserted or deleted, resulting in a shift in the reading frame. This can cause codons to be read incorrectly, leading to changes in the amino acid sequence of the protein.
Frameshift mutations can also affect the regulation of protein expression. For example, in bacteria, the Shine-Dalgarno sequence is a ribosome-binding site that is located upstream of the start codon. If a frameshift mutation occurs in this region, the ribosome may not be able to bind properly, leading to reduced protein expression. In eukaryotes, changes in the reading frame can result in premature termination codons, which can lead to the degradation of mRNA molecules and reduced protein expression.
In summary, the reading frame is essential for accurate protein synthesis, and any changes to the reading frame can have significant effects on protein expression and function.
Explain what a reading frame is and what effects it has when the reading frame is changed
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