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
___________ speciation occurs when a population is divided into geographically isolated separate subpopulations and undergoes speciation
A. allopatric
B. sympatric
C. zonal
D. hybrid
A. allopatric
what are prions
A. misfolded versions of normal brain proteins
B. tiny molecules of RNA that infect plants
C. viruses that invade bacteria
D. a mobile segment of DNA
A. misfolded versions of normal proteins
which of the statements about natural selection is most true
A. adaptations beneficial in one habitat should generally be beneficial in all other habitats as well
B. natural selection is the sole means by which a population can evolve
C. adaptations beneficial at one time should generally be beneficial during all other times as well
D. well adapted individuals leave more offspring, and thus contribute more to the next generations gene pool, than others
D. well adapted individuals leave more offspring, and thus contribute more to the next generations gene pool, than others
a trend towards the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of _________________
A. genetic drift
B. a bottleneck
C. a cline
D. relative fitness
C. a cline
which describes brightly colored peacocks mating more frequently than drab peacocks?
A. artificial selection
B. directional selection
C. sexual selection
D. disruptive selection
C. sexual selection
one species of frog live only in tree holes, another species only in streams. what kind of reproductive barrier is that?
A. behavioral
B. gametic
C. habitat
D. temporal
C. habitat
a severe drop in population size due to a sudden Environmental change can cause a change in allelic frequencies know as the ______________
A. founder effect
B. bottleneck effect
C. migration effect
D. equilibrium effect
B. bottleneck effect
a selection process that removes extreme variants and favors immediate types is called ___________________ selection
A. directional
B. disruptive
C. stabilizing
D. sexual
C. stabilizing
_______________ is the process by which one species splits into two or more species
A. mitosis
B. transport
C. catastrophism
D. speciation
D. speciation
