unit 2 (5-8)

________ molecules deliver amino acids to ribosomes during translation.

•   Messenger RNA (mRNA)

•   Transfer RNA (tRNA)

•   Ribosomal RNA (rRNA)

•   Heterogeneous nuclear RNA (hnRNA)

During ______ proteins are moved from the cytoplasm to the membrane or periplasmic space, while during ________ proteins are moved from the cytoplasm to the external environment.

•   translocation; secretion

•   secretion; translocation

•   transcription; translation

•   translocation; translation

•   secretion; translation

Key sequences exist within promoters, which vary somewhat among various promoters but are sufficiently constant that they can be represented by a sequence of bases most often found at each position. These representations are called __________ sequences. 

•   convergence

•   idealized

• consensus

•   common

In some circumstances, when two different carbon sources are available, growth will occur first using one carbon source, then after a short lag period, growth will resume using the second carbon source. This process is called __________ growth. 

•   alternating

•   bimorphic

•   diauxic

• dimorphic

In which situation might methylation of membrane proteins in Escherichia coli initiate a phosphorelay system that evokes clockwise rotation of flagella?

•   Response to an extracellular toxin.

•   Change in environmental osmotic pressure

•   Presence of a chemorepellent in the extracellular environment

•   Cellular population reaches a quorum

If the att site of Escherichia coli was dissimilar to that of lambda phage due to a mutation, how would transduction be affected?

•   Lambda phage would be unable to package host DNA.

•   Phage DNA would be unable to integrate into host DNA.

•   Specialized transduction would become generalized.vv

•   Transduction would not be affected since mutation is only in the host cell.

An Hfr cell and an F− cell result from conjugation between a donor cell and a recipient cell. Which statement is false regarding this event? 

•   The donor could have been either F− or F+.

•   The donor could have been Hfr.

•   The recipient could have been F−.

•   The donor could not have been F−.

A reciprocal exchange in which two DNA molecules with the same nucleotide sequence break and rejoin in a crossover is called __________ recombination. 

•   linear

•   site-specific

•   replicative

•   homologous

Repair of an apurinic or apyrimidinic site in DNA by AP endonuclease must be completed by the action of _________. 

•   UvrABC endonuclease

•   RecA protein

•   DNA polymerase I

•   DNA polymerase II

A mutagen that inserts between the stacked bases of a DNA double helix, distorting the DNA to induce single-pair insertions or deletions is called a(n) __________ agent. 

•   insertional

•   interspersing

• intercalating

•   distortional