Biology Chapter 17 Flashcards

Transcription in Eukaryotic Cells

• Initiation of transcription requires binding of several transcription factors to the promoter region.
• DNA strands must separate completely to expose the promoter, allowing for transcription to commence.

Codons

• A codon is a sequence of three nucleotides that codes for a specific amino acid.
• Each codon can only code for one amino acid, but multiple codons can specify the same amino acid.
• It is not true that a codon extends from one end of a tRNA molecule.

Anticodon Functionality

• The anticodon in tRNA is complementary to the corresponding codon in mRNA.
• This complementary pairing is crucial for accurate translation of mRNA into proteins.

RNA Processing

• RNA processing involves adding nucleotides to both ends of the RNA molecule and splicing by spliceosomes.
• Exons remain in the final mRNA, while introns are removed, contradicting the notion that exons are cut out.
• Ribozymes can play a role in the splicing of RNA.

Translation Components

• Translation involves mRNA, tRNA, ribosomes, and GTP, but not DNA, which is not directly involved in the translation process.

Mutations and Their Effects

• The most harmful mutation is a single nucleotide insertion close to the start of the coding sequence, as it can cause a shift in the reading frame, altering all subsequent amino acids.
• Other mutations, like a deletion of three nucleotides, may not have as catastrophic an impact due to potential reversion to the original reading frame.