the genetic material of HIV consists of
single stranded RNA
what is the function of reverse transcriptase
it catalyzes the formation of DNA from an RNA template
what is the source of a viral envelope
host cell membrane
what do we call a virus that attacks a bacterium
phage
how does HIV cause disease
hiv kills cells that defend the body against disease
the most effective way to stop viral infections
vaccines
H1N1 2009 outbreak is considered to have been which of the following
pandemic
how do prions, which are misfolded proteins, infect organisms
prions enter brain cells and cause normal forms of the protein to refold into the prion form
which characteristic, structure, or processes is common to both bacteria and viruses
genetic material composed of nucleic acid
to cause a human pandemic, the H5N1 avian flu virus would have to
become capable of human-to-human transmission
why is it ineffective to treat viral disease with antibiotics
antibiotics inhibit enzymes specific to bacteria and have no effect on virally encoded enzymes
how do prions differ from viruses
unlike viruses, prions do not include any nucleic acids, is a single molecule, and are infectious proteins
the host range of a virus is determined by
the proteins on its surface and that of the host
which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life
copies of the herpesvirus genome permanently maintained in host nuclei
which is a characteristic of the lytic cycle
large number of phages released at a time
which virus have single-stranded RNA that acts as a template for DNA
retroviruses
which can be effective in preventing the onset of viral infection in humans
getting vaccinated
describes plant virus infections
they are spread through plasmodesmata
what are prions
misfolded versions of normal brain protein
prokaryotic cells that built stromatolites and were the first to add significant quantities of oxygen to Earth’s atmosphere are classified as
cyanobacteria
streptococcus pyogenes is classified with
gram positive bacteria
spiral shaped bacteria are likely to be placed with
spirochetes
what is the function of fimbriae
they are used to attach the cell to its substrate or to other prokaryotes
bacteria that live around deep-sea, hot-water vents obtain energy by oxidizing inorganic hydrogen sulfide belched out by the vents. They use this energy to build organic molecules from carbon obtained from the carbon dioxide in seawater. These bacteria are
chemoautotrophs
which is true about obligate anaerobes
they are poisoned by O2
prokaryotic organism most likely to be found living in salt ponds are
halophiles
relationship between organisms of different species that are in direct contact can best be described as
symbiotic
true for bacteria
certain bacteria live within rocks kilometers below the earths surface
which is false about bacterial cell walls
cell walls prevent cells from dying in hypertonic conditions
The predatory bacterium, Bdellovibrio bacteriophorus, drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey’s cytoplasm?
capsule, membrane composed mostly of lipopolysaccharide, peptidoglycan, and membrane composed mostly of phospholipids
Jams, jellies, preserves, honey, and other foodstuffs with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment
undergo death by plasmolysis
Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces?
capsules and fimbriae
which statement about the genomes of prokaryotics is correct
prokaryotic genomes are composed of circular DNA
If a bacterium regenerates from an endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably also
lack antibiotic resistant genes
a prokaryote that obtains both energy and carbon as it decomposes dead organisms
heterotroph and chemotroph
an organism that obtains both carbon and energy by ingesting prey (,)
heterotroph, chemotroph
Which of the following obtain energy by oxidizing inorganic substancesenergy that is used, in part, to fix CO2?
chemoautotrophs
) If archaeans are more closely related to eukaryotes than to bacteria, then which of the following is a reasonable prediction?
archaean ribosomes should be larger than typical prokaryotic ribosomes
) Which of the following traits do archaeans and bacteria share?
presence of plasma membrane, lack a nuclear envelope
Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?
extreme halophiles
A fish that has been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile, Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would support your suspicion?
1
1
cell walls that lack peptidoglycan, cells that are isotonic to conditions on the surface of the fish, cells containing bacteriorhodopsin, the presence of very large numbers of ion pumps in its plasma membrane
If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?
The recycling of nutrients would be greatly reduced, at least initially.
Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth?
Closing previously opened containers: prevents more bacteria from entering, and excludes O2
How do humans combat infection by the Plasmodium parasite?
Cytotoxic T cells destroy infected liver cells by recognizing a Plasmodium protein bound to an HLA protein on the surface of those cells.
What advantage do organisms that reproduce sexually have over organisms that reproduce asexually?
Their offspring may be more adaptable to changes in the environment.
term that describes the fusion of two gametes to form a diploid zygote
syngamy
term that describes the multicellular haploid form of a protist that shows alternation of generations
gametophyte
structure that mediaties the attachment of spores to a surface on which to grow is
holdfast
organisms that exhibit alternation of generations reproduce sexually in the diploid stage
false
golden algae, brown algae, red algae, chlorophytes, and charophyceans are some ex of protists that are
photosynthetic
three groups that contain large algae known as seaweeds are
brown, red and green algae
characterized by glasslike walls containing silica?
diatoms
plasmodium, the parasite organism that causes malaria, is a
apicomplexan
paramecium is a
ciliate
largest seaweeds are
brown algae
group characterized by cells with fine harilike projections on their flagella
stramenopila
which algae group possess a photosynthetic pigment that allows them to live in deep water
red
Which of these groups includes both aquatic decomposers and the parasites responsible for downy mildew of grapes and late potato blight?
oomycetes
A sign on the beach states, “Beach Closed. Red Tide.” The organisms interfering with your use of this beach are probably _____.
Dinoflagellates
Archaeplastids, which include red and green algae and land plants, are thought to have descended from a heterotrophic protist that engulfed a(n) _____.
cyanobacterium
correct statement about slime molds?
Cellular slime molds form masses when food is scarce, but their cells remain separated
_____ are eukaryotic autotrophs that float near the surface of water and are the basis of the food chain.
phytoplankton
Coral bleaching, which causes high coral mortality, has been occurring widely in coral reefs. Coral bleaching actually refers to the death of symbiotic dinoflagellates living within the corals. Why does coral bleaching cause the corals to die?
Dinoflagellates provide nutrients from the products of photosynthesis to the corals in exchange for a safe place to live.
Why has the kingdom Protista been abandoned?
The kingdom Protista is polyphyletic.
protists are
eukaryotic
According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate
from engulfed, originally free-living proteobacteria
Which of the following was derived from an ancestral cyanobacterium?
chloroplast
Which two genera have members that can evade the human immune system by frequently changing their surface proteins?
plasmodium, trypanosoma
about dinoflagellates is true?
They possess two flagella.
Which process results in genetic recombination, but is separate from the process by which the population size of Paramecium increases?
conjugation
Diatoms are mostly asexual members of the phytoplankton. Diatoms lack any organelles that might have the 9 + 2 pattern. They obtain their nutrition from functional chloroplasts, and each diatom is encased within two porous, glasslike valves. Which question would be most important for one interested in the day-to-day survival of individual diatoms?
How do diatoms with their glasslike valves keep from sinking into poorly lit waters?
A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack
holdfasts
characteristic of the water molds (oomycetes)?
the presence of filamentous feeding structures
The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?
cyanobacteria → green algae → land plants
The chloroplasts of all of the following are thought to be derived from ancestral red algae, except those of
green algae
A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga probably belongs to which group?
red
Green algae differ from land plants in that many green algae
are unicellular
correctly described as a primary producer?
diatom
A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic alternation of generations is most probably what type of alga
brown
as a group, fungi are
decomposers
fungi release digestive enzymes into their
surroundings
basidia produce spores by a process known as
meiosis
fungi produce
haploid spores
karyogamy produces
diploid spores
zygosporangia are
heterokaryotic
describes the fusion of cytoplasm from two individuals
plasmogamy
in fungi, fertilization is complete after the cells fuse together
false
meiosis in a mushroom
occurs in the basidia
allows the growing mushroom to nourish itself
mycelium
most cells in a mushroom contain haploid nuclei
true
diff. between plants and fungi
fungi are heterotrophic, plants are autotrophic
