Chapter 17

In eukaryotic cells, transcription cannot begin until (A) the two DNA strands have completely separated and exposed the promoter. (B) several transcription factors have bound to the promoter. (C) the 5 ' caps are removed from the mRNA. (D) the DNA introns are removed from the template.

Which of the following is true of a codon? (A) It never codes for the same amino acid as another codon. (B) It can code for more than one amino acid. (C) It can be either in DNA or in RNA (D) It is the basic unit of protein structure.

The anticodon of a particular tRNA molecule is (A) complementary to the corresponding mRNA codon. (B) complementary to the corresponding triplet in rRNA. (C) the part of tRNA that bonds to a specific amino acid. (D) catalytic, making the tRNA a ribozyme.

Which of the following is true of RNA processing? (A) Exons are cut out before mRNA leaves the nucleus. (B) Nucleotides are added at both ends of the RNA. (C) Ribozymes may function in the addition of a 5 ' cap. (D) RNA splicing adds a poly-A tail to the mRNA.

Which component is directly involved in translation? (A) RNA polymerase (C) spliceosome (B) ribosome (D) DNA

Which of the following mutations would be most likely to have a harmful effect on an organism? (A) a deletion of three nucleotides near the middle of a gene (B) a single nucleotide deletion in the middle of an intron (C) a single nucleotide deletion near the end of the coding sequence (D) a single nucleotide insertion downstream of, and close to, the start of the coding sequence

Evolution accounts for the unity and diversity of life, and the continulty of life is based on heritable information in the form of DNA. In a short essay (100-150 words), discuss how the fidelity with which DNA is inherited is related to the processes of evolution.