biology test 12- viruses and bacteria
NOTE
*be able to label all parts of a bacteria*
NOTE
*be able to label all parts of a virus*
virulent phage
A phage that reproduces only by a lytic cycle is called a ________ ______
small, nuclei, cell walls
Archaebacteria and Eubacteria are equally _____, lack ______, and have ____ _____
decomposers
Bacteria are ____________ that help to recycle the essential chemical elements in living things
bacterium, viruses
Martinus Beijerinck used filtration experiments to prove that an agent smaller than a _________ was causing tobacco mosaic disease. He was the first to name these very small particles "________".
pili
____ are shorter and thinner than flagella
cocci, bacilli, spirilla
_____ are spherical _______ are rod-shaped ________ are spiral shaped or curved
oxygen, anaerobic
_______ is poisonous to methanogens; they must live in __________ environments such as deep fresh water, marine mud, swamp mud, and sewage
symbiosis
a close and permanent association between organisms of different species
pathogen
a disease-causing agent
autotrophs
a few bacteria are __________, meaning they have the ability to make their own food
true nucleus, membrane-bound organelles
a prokaryotic cell does not have a ____ ________ or ________-_____ __________.
dormant, death
a retrovirus may remain _______ for some length of time, but will eventually become active, causing the host cell to make new viruses and causing the _____ of the host cell
plasmid DNA
a small circular piece of DNA that is separate from the chromosome; generally one gene
binary fission
a type of asexual reproduction where one cell undergoes cell division to form two identical cells
conjugation
a type of bacterial reproduction where a hollow bridge forms between two bacterial cells
genetic material
a viral infection begins when the _______ _______ (DNA or RNA) makes its way into a host cell
living cell, ceases
a virus is only active when it's inside a ______ ____; when removed, it _______ all activities but retains its ability to infect the cell
vaccine
a weakened or killed form of the pathogen that stimulates the body's immune system to produce antibodies
binary fission, increase
after conjugation, cells go back to _______ ______ and ________ in number
carbon, nitrogen, essenial elements
all living things depend upon a constant supply of ______, ________, and other ________ ________; these ^^ must be recycled when an organism dies.
parasites, host
all viruses are _________ and require a ____
inside, thick wall
an endospore is formed _______ of a cell; the contents of the cytoplasm draw up together and a ______ ____ is formed around it
virus
an infectious particle that is nonliving
animal proteins
animals eat the plants, and convert the plant proteins into ______ _______
bacteria
are antibiotics affective against bacteria or viruses?
rapid cell division, metabolic diversity
bacteria are successful because of their _____ ____ ________ (reproduction) and their great _________ ________
foods, beverages
bacteria are used to produce a variety of _____ and _________
large
bacteria are very ______ in comparison to a virus
living world
bacteria are vital to maintaining the ______ ______
20 minutes, forms of life
bacteria can double their numbers every __ _______ and live in environments that support no other ____ __ ____
cellular respiration, fermentation
bacteria release energy through the processes of __________ __________ or ___________ or both
separate domains
biologists now recognize that there are such great differences between two distinct groups of prokaryotes that they should be placed into __________ ________
adhere, substrate
capsules enable prokaryotes to _____ to their ___________ or to other individuals in the colony
antibiotics
compounds that kill bacteria
viroids
consist of small, circular molecules of RNA, but they have no protein coat; tiny molecules of naked circular RNA
prions
disease-causing particles that do not contain DNA or RNA
dryness, heat, cold, dormant
endospores can survive extreme ________, ____, or ____; they can remain _______ for months or years while waiting for favorable growth conditions to return
"true" bacteria
eubacteria are the "____" _______
environmental conditions
eventually, certain _____________ __________ (chemicals, radiation) may trigger the switchover from the lysogenic cycle to the lytic cycle
salt-loving
halophiles are ____-_______ bacteria; they live in environments that have very high ^^ concentrations, such as the Great Salt Lake and the Dead Sea
The leading hypothesis is that a prion is a misfolded form of a protein normally present in brain cells. When a prion enters a cell that contains the normal form of the protein, the prion converts the normal protein to the prion version.
how can a protein, which cannot replicate itself, be a pathogen?
he was able to isolate crystals in a virus sample; living organisms don't crystallize, so therefore viruses aren't alive
how did Stanley infer that viruses aren't alive?
they convert hydrogen gas and carbon dioxide into methane gas
how do methanogens get energy?
by getting the cell to produce viral parts instead of cell parts
how do viruses reproduce in living cells?
incredible rates
if conditions are favorable for growth, bacteria can grow and divide at ___________ ______
enters, copies, burst
in a lytic infection, a virus ______ a cell, makes _______ of itself, and causes the cell to _____
nitrogen fixation
in a process called ________ _________, bacteria are able to convert nitrogen gas into nitrates, a form that plants can use
capsule, polysaccharide
in bacteria, a ______ may be present outside of the cell wall; it is composed of a gluey ____________
double, DNA
in binary fission, the bacterium grows to nearly _______ its size, then replicates its ___ and divides in half
genes
in conjugation, ______ move from one cell to the other through the tube
numbers, genetic diversity
in conjugation, there is no increase in gene ________, but they have redistributed the genetic information; the transfer of genetic information increases _______ _________ in future populations
-the eventual exhausting of food supply -being poisoned by their own metabolic waste -competition from other microbes -being consumed by other organisms
in reality, prokaryotic reproduction is limited by :
indefinitely
in the lysogenic cycle of viral reproduction, the host cell makes copies of the viral genetic material __________
host cell
in the lysogenic cycle, the virus incorporates its DNA into the DNA of the ____ ____; the viral DNA is then replicated along with the host cell's own DNA
parasites
live in or on other organisms and cause them harm
-they can reproduce but only inside a living cell -they can mutate or change -they have DNA or RNA; their genome may consist of only 4 genes, or up to 100 genes
living characteristics of viruses:
20 minutes, 3 days
many bacteria can divide every __ _______ (under ideal conditions); if reproduction continued unchecked at this rate, a single prokaryotic cell could give rise to a colony outweighing Earth in __ ____
cows, termites
methanogens also thrive in the digestive tracts of _____ and _______; ^^ can release 200 to 400 liters of methane gas per day.
heterotrophs
most bacteria are ___________, meaning they do not have the ability to make their own food
reproduction, slow
new drugs have been developed that interfere with _____________ of viruses, but only ____ the effect of the virus; they do not provide a cure
80, directly
nitrogen gas makes up about ___ percent of Earth's atmosphere, but plants and animals are not capable of using it ________
-they are non-cellular -they have no metabolism; they have no food or energy requirements -they can be crystallized and dehydrate and stored indefinitely; they come to "life" only when injected inside a living cell
non-living characteristics of viruses:
assembles
once a host cell makes copies of viral DNA and protein capsids, the host _______ the parts into viruses
viral genome
once a virus hijacks and reprograms a cell, the _____ _______ takes over the host cell and makes the host cell start producing viral parts
hijacks, reprograms
once a virus is inside a cell, it _______ and _________ it
protein capsids
once the viral genome takes over the host cell, the host cell will begin to make copies of the viral DNA and producing the ________ ________
facultative anaerobes
organisms that can survive with or without oxygen; do not require oxygen, but neither are they killed by its presence; allows these organisms to live just about anywhere
obligate aerobes
organisms that require a constant supply of oxygen in order to live
recognize
our immune system launches a response to the harmless form (vaccine), thereby learning to __________ it the next time that we are exposed to it
photoautotrophs
photosynthetic organisms that use light energy from the sun to convert carbon dioxide and water into the organic molecule glucose and oxygen
-a food source -the surface of a liquid -another bacteria during reproduction
pili serve to attach bacteria to :
nitrogen, proteins
plants and animals must have ________ to build amino acids; amino acids are needed to build ________
plant proteins
plants take up nitrates created by nitrogen fixation through their roots and use them to build _____ _______
protein
prions are tiny bits of _______
mad cow disease
prions cause degenerative brain diseases such as:
-shape -the materials composing of the cell wall -the way they move -the way they obtain energy
prokaryotes are identified by several characteristics :
biosphere, eukaryotes
prokaryotes dominate the _________; their collective biomass outweighs all __________ combined by at least 10 fold
immunity
rapid response of the immune system because of vaccines
cancer
retroviruses are responsible for types of ______
RNA, DNA
retroviruses have ___ as their genetic information rather than ___
reverse transcriptase, chromosome
retroviruses have an enzyme called _______ ___________, which transcribes their RNA template into DNA; the newly made DNA then enters the cell's nucleus and integrates into the DNA of a __________
dead organic matter, decomposers
saprophytes live on _____ ______ ______; they are very important as __________
highly specific
since viruses must bind precisely to proteins on the cell surface, they are _____ _______ to the cells they infect
motile
some bacteria are ______ and other do not move at all
harmful, benign
some bacteria are ________ and cause diseases, but most bacteria are _______ or beneficial; a relatively small number of species cause disease
pathogenic
some bacteria are __________ (cause diseases)
oil
some bacteria can digest ___ and are helpful in cleaning up oil spills
obligate anaerobes
some bacteria don't require oxygen and are killed in its presence; these organisms must live in the absence of oxygen
flagella, slime
some bacteria move by means of _________, which are whip-like structures used for movement; some lash or whip forward; others slide over a layer of _____ they secrete
dehydration, attacks
some capsules protect against ___________; some capsules shield pathogenic bacteria from _________ by their host's immune system
mutualism
symbiosis that is beneficial to both species
parasitism
symbiosis where one species benefits and the other is harmed
commensalism
symbiosis where one species benefits from the association while the other is neither harmed nor helped
peptidoglycans, membrane lipids
the Archaebacteria lack the _____________ found in the eubacteria; they also have different _______ ______
eukaryotes, eubacteria
the DNA sequences of key archaeological genes in Archaebacteria are more like those of _________ than those of ________
cytoplasm
the ________ of bacteria does not contain any membrane bound organelles
harsh environments
the archaebacteria live in extremely _____ _____________, such as : swamps, salt lakes, and hot springs
prokaryotes
the bacteria are ___________
vaccines
the battle against viral diseases lies in the use of _________
-suitable temperature : 80-100°F -moisture -suitable food source -darkness -space to grow
the best environment for growth of bacteria has :
receptors
the capsid has a particular shape that must match __________ on the surface of a host cell; when the virus attaches to these ^^, the cell is "tricked" into letting the virus inside
proteins
the capsid is made of _______ that enable the virus to enter the host cell
one single, circular, continuous
the chromosome of bacteria consists of ___ ______, ________, _________ molecule of DNA
ribosomes
the cytoplasm is filled with many ___________
peptidoglycan
the eubacteria have a cell wall that contains a polysaccharide called _____________
saprophytes, parasites
the heterotrophic bacteria are further divided into ____________ and _________
infectious agent, disease
the important lesson we have learned from viroids is that a molecule can be an __________ _____ and cause _______
host
the living organism a parasite lives on
generations
the prophage in a lysogenic infection may remain part of the host for many __________ before becoming active
capsid
the protein coat that surrounds the DNA or RNA on a virus
virology
the study of viruses
prophage
the viral DNA embedded into the host cell's DNA
hundreds of thousands
the viral reproductive cycle ends with the exit of ________ __ _________ of viruses from the infected host cell
archaic, ancient, millions
the word "archaea" means "_______ or _______" since many of the known species of archaea live in extreme environments thought to resemble the harsh environments present ________ of years ago
poison
the word virus comes from the Latin word meaning "_______"
environment
there is great variety in the organisms that belong to Eubacteria; these bacteria are found in every ____________ on Earth
hydrothermal vents
thermoacidophiles are often found around ____________ _____ (black smokers) that leak very hot, dark-colored, acidic water
acidic, high
thermoacidophiles live in very ______ environments that have very ___ temperatures, such as the hot springs in Yellowstone National Park (these organisms can thrive in temperatures of 110°C and at a pH of less than 2)
false; does not kill right away because it remains inactive for a long period time
true/false: lysogenic viruses kill the cell right away because they may remain active for some period of time
false; plant viruses only infect plant cells, and animal viruses only infect animal cells
true/false: plant viruses infect animal cells, and animal viruses infect plant cells
true
true/false: prokaryotes can easily survive without eukaryotes, but eukaryotes are totally dependent on prokaryotes
true
true/false: there is little that can be done to cure a viral infection
true
true/false: viral reproduction often destroys the host cell
false; they aren't
true/false: viruses are affected by antibiotics
true
true/false: viruses can reproduce, but only inside a living cell
Eubacteria
under a microscope, Archaebacteria look very similar to the __________
Monera
until recently, all prokaryotes were placed in a single kingdom called the ______ kingdom
chemoautotrophs
use the energy from inorganic reactions as a source of energy to build molecules of glucose
simplicity, size
viroids are known for their extreme _________ and small ____; they are much smaller than a virus
plants, animals
viroids have only been identified in ______, but they are suspected of causing some diseases in _______ for which no pathogen has ever been isolated
non-cellular
viruses are ___-________, meaning they are not made of cells and have no cell parts
small, electron microscope
viruses are extremely _______; most can only be seen with an ________ __________
crystallized
viruses may be ____________ and stored indefinitely, but even after long periods of time, they retain their ability to infect a living cell
tissue specific
viruses of eukaryotes are usually ______ ________
size, structure
viruses vary widely in terms of ____ and _________
Staphylococcus Streptococcus
what are 2 types of pathogenic diseases?
sour cream, yogurt, and cheese
what are examples of bacteria in foods and beverages?
-colds -hepatitis -flu -west nile virus -chicken pox -AIDS
what are some common viral diseases?
DNA or RNA surrounded by a protein
what are the 2 parts viruses consist of?
-other bacteria release toxins or poisons in the body of the host -some bacteria damage the cells and tissues by breaking down the cells for food
what are the 2 ways bacteria produce diseases?
-methanogens -halogens -thermoacidophiles
what are the 3 archaea groups?
AIDS
what is an example of a retrovirus?
d = Archaea k = Archaebacteria
what is the domain and kingdom of Archaea?
d = Bacteria k = Eubacteria
what is the domain and kingdom of Bacteria?
Release: -the cell swells, bursts, and releases 100's of new viruses
what is the fifth step of the lytic cycle? explain it.
Attachment: -tail fibers are used to attach to receptor sites on the surface of the host cell
what is the first step of the lytic cycle? explain it.
Assembly: -the viral DNA or RNA is assembled inside the protein coat
what is the fourth step of the lytic cycle? explain it.
lytic- viral DNA completely takes over host cell DNA lysogenic- viral DNA shares cell with host DNA, so that each new reproduced cell will be part viral DNA and part host cell DNA (stress event will eventually trigger viral DNA)
what is the main difference between the lytic cycle and the lysogenic cycle?
Entry: -phage DNA is injected; empty capsid remains outside; host cell DNA is destroyed
what is the second step of the lytic cycle? explain it.
Synthesis: -the host cell is directed to produce viral genomes and protein capsids
what is the third step of the lytic cycle? explain it.
they enter living cells and use the machinery of the cell to produce more viruses
what thing do all viruses have in common?
decompose, nitrogen
when an organism dies, bacteria ___________ the organism, returning ________ to the ecosystem to be used again
simpler materials
when an organism dies, it is attacked by bacteria and broken down into _______ __________
endospores
when conditions for growth become unfavorable, many bacteria form structures called ____________
much faster
when we are exposed to the "real" pathogen (after a vaccine), our immune system can respond ____ _______ since it has already learned to recognize the pathogen
lytic cycle and lysogenic cycle
which two processes may occur once virus is inside a host cell?
Wendell Stanley
who inferred that viruses aren't alive?
Martinus Beijerinck
who is considered the founder of virology?
anything that will kill the virus will also kill the host (ex.- poison)
why aren't viruses affected by antibiotics?
