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Genetic Code quiz #4 Flashcards

Genetic Code quiz #4
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  • Describe the three main steps involved in using the genetic code to translate a DNA sequence into a protein.
    The three steps are: (1) Transcribe the DNA coding strand into mRNA by replacing thymine (T) with uracil (U); (2) Identify the codons in the mRNA by grouping nucleotides into sets of three, starting with the start codon and ending with a stop codon; (3) Use the genetic code to translate each codon into its corresponding amino acid until a stop codon is reached.
  • What is the significance of start and stop codons in the genetic code?
    The start codon (usually AUG) signals the beginning of protein synthesis and codes for methionine, while stop codons (such as UAA, UAG, and UGA) signal the end of translation and do not code for any amino acid, thus terminating protein synthesis.
  • What is a codon and where is it found during protein synthesis?
    A codon is a three-nucleotide sequence found in messenger RNA (mRNA) that specifies a particular amino acid during protein synthesis.
  • What is the first step in using the genetic code to translate a DNA sequence into a protein?
    The first step is to transcribe the DNA coding strand into mRNA by replacing all thymines (T) with uracils (U).
  • How do you identify codons in an mRNA sequence?
    Codons are identified by grouping the mRNA sequence into sets of three nucleotides, starting with the start codon and ending with a stop codon.
  • What is the function of the start codon in the genetic code?
    The start codon, usually AUG, signals the beginning of protein synthesis and codes for the amino acid methionine.
  • What role do stop codons play in protein synthesis?
    Stop codons (such as UAA, UAG, and UGA) signal the end of translation and do not code for any amino acid, thus terminating protein synthesis.
  • How is the genetic code table used to determine which amino acid corresponds to a codon?
    The first letter of the codon determines the row, the second letter determines the column, and the third letter specifies the position within the box to find the corresponding amino acid.
  • Why is the genetic code considered nearly universal among organisms?
    The genetic code is nearly universal because it is consistent across almost all organisms, with only rare exceptions.
  • What is the sequence of amino acids produced from the mRNA codons AUG, CAU, ACC, UGU, and UAA?
    The sequence is methionine, histidine, threonine, and cysteine, with UAA serving as a stop codon that ends translation.