Biology, Eighth Edition (Raven)

Chapter 15: Genes and How They Work

Post Test

1
Why are nutritional mutations particularly helpful in studying the molecular basis of heredity? (p. 279)
A)There are many more genes involved in nutritional enzymes than for any other genetically-encoded feature of a cell.
B)Such mutations aren't lethal because you can grow the organism on media supplemented with compounds that can't be made.
C)Genes for enzymes involved with metabolic deficiencies are more unstable than other genes and can mutate more easily.
D)Organisms which grow on minimal media have fewer genes than those which grow on more complex media.
E)Genes which encode enzymes for metabolic reactions absorb X-rays better than other nucleotide sequences.
2
How was the genetic code deciphered? (p. 281)
A)Synthetic mRNAs were created with known sequences, and the amino acid order created from them was determined.
B)Bacteria were "fed" mRNA from other types of cells and created enzymes they ordinarily would not have made.
C)The codon table was hypothesized by Francis Crick and experiments confirmed his ideas about how tRNA interacted with mRNA to order the amino acids.
D)Polypeptides were exposed to cell-free systems and the mRNAs which would have made them in a living cell gradually accumulated by reversing the synthesis reactions.
E)Each codon was hypothesized to encode for a particular amino acid, and subsequent experiments ruled out the incorrect hypotheses.
3
Which form of RNA is involved with processing transcripts to make mRNA? (p. 284)
A)miRNA
B)siRNA
C)snRNA
D)SRP RNA
E)rRNA and tRNA together
4
Which part of the prokaryote RNA polymerase holoenzyme is involved with recognizing promoters specific to certain types of genes? (p. 284)
A)Alpha
B)Beta
C)Beta prime
D)Sigma
E)Delta
5
In prokaryotes, RNA polymerase can bind "naked" sequences upstream of promoters. Eukaryotes need protein "decorations" to facilitate RNA polymerase binding. What is the name of these proteins which assist RNA polymerase with binding? (p. 287)
A)TATA box proteins
B)Introns
C)Exons
D)Transcription factors
E)Methyl-G cap
6
When the human genome was first sequenced, scientists expected to find around 100 000 genes (which corresponded to the estimated number of different proteins in a human). Upon its completion and analysis of reading frames, they discovered the number was more likely 25 000. What is the most likely explanation for this? (p. 290)
A)Gene editing
B)Alternative splicing
C)Exon shuffling
D)Intron excision
E)Mutation
7
Which is responsible for the production of a peptide bond between adjacent amino acids during translation? (p. 292)
A)Peptidyl transferase activity of the large subunit.
B)Proteins in the large and small subunit of the ribosome.
C)Ribozyme activity of tRNA.
D)The charging effect of aminoacyl tRNA synthetase.
E)Condensase activity of the small subunit.
8
What is the order of events involved in translation of a prokaryotic mRNA? (p. 293)
  1. attachment of the initiator tRNA onto the start codon
  2. binding of the small ribosome subunit to the RBS
  3. attachment of the large ribosome subunit to the mRNA
  4. translocation of the ribosome to move a new codon to be in the A site
  5. entry of a charged tRNA into the A site
A)I, II, V, III, IV
B)II, I, III, V, IV
C)I, II, III, V, IV
D)II, I, IV, III, V
E)III, I, II, IV, V
9
Imagine that a molecular biologist cuts out the amino acid sequence for a eukaryotic gene and places it in a prokaryotic chromosome, just downstream of a promoter. What would be the most likely result, assuming RNA polymerase can still identify and bind the promoter? (p. 298)
A)The cell would die because eukaryotic proteins are not compatible with prokaryotic cell metabolism.
B)The prokaryote would start to demonstrate eukaryotic gene expression activities, such as transporting the mRNA to different locations.
C)An mRNA would form, but would it would be much longer than that formed directly from the template in the original eukaryote.
D)A protein would form, but one that's based on an entirely different genetic code than the original (i.e. the prokaryotic code rather than the eukaryotic code).
E)If the ribosome could bind the mRNA, a polypeptide that is longer than the one from the original eukaryote would be created.
10
Rank the following types of mutation in the likely order of their severity in genotype (that is, from least disruptive to phenotype to most disruptive). (p. 299)
  1. missense
  2. nonsense
  3. frameshift
  4. silent
A)I, III, IV, II
B)IV, III, I, II
C)IV, I, III, II
D)IV, I, II, III
E)I, II, IV, III
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