bio chapter 20
true or false: like bacteria, a single type of virus can infect many different types of organisms
false
true or false; once inoculated with an influenza vaccine, an individual is immune to that strain of virus for life
false
bacteria use _____ to attach to surfaces or other cells
fimbriae
which bacterial structure is used for locomotion?
flagellum
what does a virus direct a host cell to duplicate?
genetic material
characteristics of a virus
-consists of either DNA or RNA -surrounded by a protein coat -do not have a metabolism -do not respond to stimuli -can replicate only by using metabolic machinery of a host cell
an organism that is unable to grow in the absence of oxygen is a(n):
obligate anaerobe
infectious particle consisting of protein only and no nucleic acid (usually associated with mad cow disease)
prion
organisms that lack a membrane-bounded nucleus and membranous organelles typical of eukaryotes
prokaryotes
an infectious strand of RNA devoid of capsid and much smaller than a virus:
viroid
list the following from smallest to largest. Begin with the smallest at the top of the list. virus, viroid, eukaryote, prokaryote
viroid, virus, prokaryote, eukaryote
an obligate intracellular parasite that can only replicate using a host cell: ______
virus
what portion of an animal virus binds to the host cell membrane?
virus spikes
who was the first person to suggest the existence of a virus , suspecting that it was the cause of rabies?
Louis Pasteur
virus
Noncellular parasitic agent consisting of an outer capsid and an inner core of nucleic acid
during the biosynthesis stage of a retrovirus replication cycle, viral ___ is used to produce viral _____
RNA; DNA
bird flu, zika and west nile encephalitis are all examples of _____ viral diseases
emerging
how can animal viruses enter a host cell?
endocytosis
what is plasmid?
extra rings of DNA that usually carry accessory genes
viruses are ____ specific because each can only infect one type of living cell
host
the viral enzyme found in retroviruses that is capable of converting their RNA genome into a DNA copy is called _____
reverse transcriptase
a bacterium that functions as a decomposer to break down organic matter of dead organisms is called a(n) _______
saprotroph
mutualism, commensalism, and parasitism are all examples of _____ relationships
symbiotic
the disease that results from bacterial infection that involves sustained muscle contraction without relaxation is called ______
tetanus
true or false; viruses are not considered to be a living organism
true
mad cow disease and kuru are examples of _______diseases because they destroy nerve tissue in the brain
neurodegenerative
a cytoplasmic region of prokaryotic cells where chromosomal DNA is located
nucleoid
viruses are known as ______
obligate intracellular parasites
how are viruses classified?
only lower taxonomic levels are used for virus classification including genus and species
on average, the size of a virus is about _____
10-400 nm
the retrovirus responsible for causing AIDS is
HIV
a lichen results from a symbiotic relationship between cyanobacteria and what?
a fungus
halophiles, methanogens, and thermoacidophiles are the three main groups of _______
archaea
order the steps of viral reproduction beginning with the first step at the top; attachment, biosynthesis, maturation, release, penetration, integration
attachment, penetration, integration, biosynthesis, maturation, release
a virus that infects only bacterial cells is called a(n)
bacteriophage
the reproductive mechanism which is utilized by most prokaryotes:
binary fission
a dramatic increase in cyanobacterial numbers in a lake as a result of human pollution is called a cyanobacterial ______
bloom
the protective protein coat surrounding the genetic material of a virus:
capsid
which of the following are found in all viruses? envelope, capsid, nucleic acid core, proteins
capsid, proteins, nucleic acid core
which structure of a prokaryotic cell prevents the cell from bursting or collapsing due to fluid pressure changes?
cell wall
bacteria that obtain their carbon and energy by consuming organic nutrients produced by other living organisms are called _______
chemoheterotrophs
a virus is similar in size to a(n)
large protein
the viral reproductive cycle in which viral DNA is incorporated into the host's genome is called the _____ cycle
lysogenic
the viral reproductive cycle that terminates with the destruction of the host cell through cell lysis is called the ______ cycle
lytic