Indicate whether each of the following statements about the genetic code is true
ID: 49355 • Letter: I
Question
Indicate whether each of the following statements about the genetic code is true or false. 1. The genetic code is read in groups of 4 bases. 2. The genetic code includes specific start and stop codons. 3. The genetic code is the same in almost all living organisms. 4. Deleting a single base from an mRNA molecule usually alters one codon only. 5. The codons do not overlap each other 6. There is only one start codon. 7. Stop codons have a dual function because each one also codes for an amino acid. 8. There are 66 possible codons. 9. Special spacer proteins are used to mark the end of one codon and the start of the next codon.Explanation / Answer
False, George Gamow proposed that the set of 3 bases must be employed to encode 20 standard amino acids for making proteins by the living cells True, A codon is defined by the initial nucleotide from which the translation starts, Translation starts with initiation codon or Start Codon and Stop codon is given as UAA ochre, UGA opal or UAG amber True, The genetic code for all living organisms, is same. It is the arrangement of these codons which bears the changes. False, Deleting a single base from mRNA molecule does not alter only one codon, but the insertion or deletion will affect every codon. True, Codons donot overlap each other, if they did the change due to mutation would alter one or more amino acids. True, There is only one start codon where as three stop codons as discussed earlier. False, Stop codons also known as nonsense codon, stop codons do not code for amino acids False, There are 64 possible codons, i.e. 43 =64. Out of which 54 sequences were determined by Leder and Nirenberg. False, Spacer are the sequence between each of the protein coding regeions, where as stop codon is used as terminal codon