A minimal genetic code requires only 21 codons—one for each amino acid, and one for a stop signal. Given this, what advantage might be offered by having a code with 64 codons?

Using the genetic code (Table 10.1), list the order of amino acids encoded by the following mRNA nucleotides: CAACGCAUUUUG.

Which of the following describes the experimental strategy that was used to decipher the genetic code?a. comparing the amino acid sequences of proteins with the base sequence of their genesb. analyzing the sequence of RNAs produced from known DNA sequencesc. analyzing mutants that changed the coded. examining the polypeptides produced when RNAs with particular sequences were translated

Which of the following describes the experimental strategy that was used to decipher the genetic code?a. comparing the amino acid sequences of proteins with the base sequence of their genesb. analyzing the sequence of RNAs produced from known DNA sequencesc. analyzing mutants that changed the coded. examining the polypeptides produced when RNAs with particular sequences were translated

For each of these statements about the genetic code, select True or False.a. T/F Wobble pairing accounts for the redundancy of the genetic code.b. T/F There are 64 different tRNAs that read the 64 possible codons.c. T/F All possible codons are used, but not all codons specify an amino acid.d. T/F Some codons are recognized by proteins, not by tRNAs.

For each of these statements about the genetic code, select True or False.a. T/F Wobble pairing accounts for the redundancy of the genetic code.b. T/F There are 64 different tRNAs that read the 64 possible codons.c. T/F All possible codons are used, but not all codons specify an amino acid.d. T/F Some codons are recognized by proteins, not by tRNAs.

A minimal genetic code requires only 21 codons—one for each amino acid, and one for a stop signal. Given this, what advantage might be offered by having a code with 64 codons?

Using Figure 17.6, identify a 5′→3′ sequence of nucleotides in the DNA template strand for an mRNA coding for the polypeptide sequence Phe-Pro-Lys. a. 5′-UUUCCCAAA-3′b. 5′-GAACCCCTT-3′c. 5′-CTTCGGGAA-3′d. 5′-AAACCCUUU-3′

Draw a hypothetical metabolic pathway in Neurospora crassa composed of five substrates, five enzymes, and a product called nirvana. Number the substrates 1–5, and label the enzymes A–E, in order. (For instance, enzyme A catalyzes the reaction between substrates 1 and 2.) (b) Suppose a mutant strain can survive if substrate 5 is added to the growth medium, but it cannot grow if substrates 1, 2, 3, or 4 are added. Which enzyme in the pathway is affected in this mutant?