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BIOS 105 Chapter 16
- Why might a point mutation in DNA make a difference in the level of a protein's
activity?:
Answer It might substitute a different amino acid in the active site.
- The genetic code is essentially the same for all organisms. From this, one can logically
assume which of the following?:
Answer A gene from an organism can theoretically be expressed by any other organism.
3. Which of the following contradicts the one-gene, one-enzyme hypothesis?:
Answer A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally.
4. Codons are part of the molecular structure of .:
Answer mRNA
- All three domains (Bacteria, Archaea, and Eukarya) follow the same genetic code.
Therefore, which of the following statements would most likely be cor- rect?:
Answer The genetic code evolved before the different domains diverged.
- The most commonly occurring mutation in people with cystic fibrosis is a deletion of a
single codon. This results in .:
Answer a polypeptide missing an amino acid
- Which of the following mutations is likely to cause the most dramatic phenotypic
change?:
Answer a single nucleotide deletion in an exon coding for an active site
8. Which of the following is directly related to a single amino acid?:
Answer the three-base sequence of mRNA
9. Genotype is to as phenotype is to .:
Answer DNA base sequence; physical traits that are products of the proteins produced 1 / 2
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- Which of the following is NOT synthesized from a DNA template?
- ribosomal RNA
- messenger RNA
- transfer RNA
D) amino acids:
Answer D) amino acids
11. A mutation that results in premature termination of translation .-:
Answer is a nonsense mutation
12. A nonsense mutation in a gene .:
Answer introduces a premature stop codon into the mRNA
- The "universal" genetic code is now known to have exceptions. Evidence for this can be
found if which of the following is TRUE?:
Answer if UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only) in a different organism
- Which of the following is an exception to the central dogma?
- the discovery of ribozymes
- the discovery of RNA viruses that synthesize DNA using reverse transcrip- tase
- the discovery that the Archaea and Bacteria are more distantly related than are Archaea and
Eukarya
D) the discovery of DNA as the unit of genetic inheritance:
Answer B) the discovery of RNA viruses that synthesize DNA using reverse transcriptase
15. The statement "DNA -> RNA -> Proteins" :
Answer is known as central dogma
16. A frameshift mutation could result from:
Answer either an insertion or a deletion of a base
17. In the process of transcription, .:
Answer RNA is synthesized
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