test 4 multiple choice Flashcards
why are viruses referred to as obligate parasites?
A. they cannot reproduce outside a host cell
B. viral DNA always inserts itself into host DNA
C. they invariably kill any cell they infect
D. they can incorporate nucleic acid from other viruses
A. they cannot reproduce
which of the following is characteristic of the lytic cycle
A. many bacterial cells containing viral DNA are produced
B. viral DNA is incorporated into host genome
C. the viral genome replicates without destroying the host
D. a large number of phage is released at a time
D. a large number of phage is released at a time
which of the following terms describes bacteriophage DNA that has become integrated into the host cell
A. transposons
B. prophages
C. t-even phages
D. plasmids
B. prophages
catastrophism, meaning the regular occurrence of geological or meteorological disturbances, was cuviers attempt to explain the existence of
A. evolution
B. the fossil record
C. uniformitarianism
D. natural selection
B. the fossil record
natural selection is based on all of the following except
A. genetic variation exists in populations
B. the best-adapted individuals tend to leave the most offspring
C. populations tend to produce more individuals than the environment can support
D. populations do not have genetic variation
D. populations do not have genetic variation
which of the following is a true statement concerning genetic variation
A. it is created by the direct action of natural selection
B. it arises in response to changes to the environment
C. it must be present in a population before natural selection can act upon the population
D. none of the above
C. it must be present in a population before natural selection can act upon the population
when we say that an individual organism has greater fitness than another individual, we specifically mean that the organism
A. lives longer
B. can run faster
C. leaves more viable offspring
D. Utilizes resources more efficiently
D. utilizes resources mor efficiently
a certain species of land snail exists as either cream color or solid brown color. intermediate individuals are extremely rare. which of the following terms best describes this?
A. artificial selection
B. directional selection
C. stabilizing selection
D. disruptive selection
C. stabilizing selection
for a population to be at hardy Weinburg equilibrium the following conditions must exist except
A. population must be small
B. mating is random
C. no genetic drift
D. no mutations
A. population must be small
if a population is at hardy Weinburg equilibrium, its allelic frequencies are
A. increasing
B. decreacing
C. remaining constant
D. changing
C. remaining constant
stretches of DNA that can move from one location to another within the genome are called __________ elements
A. movable
B. jumping
C. transposable
D.psudo
C. transposable
when does exon shuffling occur?
A. as the result of faulty DNA repair
B. during DNA replication
C. as an alternative splicing pattern in post-transcriptional processing
D. during transcription
C. as an alternative splicing pattern in post-transcription processing
__________ of the human genome actually encodes for proteins, rRNAs or tRNAs
A. 85%
B. 25%
C. 50%
D.1.5%
D. 1.5%
multigene family’s are
A. found in telomeres
B. groups of enhancers that control transcription
C. identical or similar genes that have evolved by gene duplicating
D. made up of repetitive DNA sequences
C. identical or similar genes that have evolved by gene duplicating
_________ are offspring that result from an interspecific mating
A. mutants
B. hybrids
C. clones
D. polyploids
B. hybrids
