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BACTERIA
OBJECTIVES 19.1
Explain how the two groups of prokaryotes
differ.
Describe the factors that are used to identify
prokaryotes
Explain why bacteria are vital to maintaining the
living world.
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____________ life covers nearly every square
centimeter of the Earth.
The smallest most common microorganisms are
____________ – unicellular and lack a nucleus.
Prokaryotes typically range in
size from 1 to 5 micrometers.
there are exceptions as the one
in the graphic, it is 500 micro
meters long.
Epulopiscium fisheloni
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Until recently, all prokaryotes were placed in a
single kingdom – _______.
Monera has been divided into two different
groups: the _______ and the ____________.
Eubacteria, the larger of the two kingdoms of
prokaryotes.
Eubacteria live almost everywhere.
The live in _____ and salt water, on land and on
and within humans
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E. coli
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Eubacteria are usually surrounded by a cell wall
(_________) that protects the cell from injury
and determines its shape.
Inside the cell ____ is a cell membrane that
surrounds the cytoplasm.
Some eubacteria has a second cell membrane
that makes them especially resistant to damage.
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Archaebacteria lack the
peptidoglycan of eubacteria
and also have different
membrane _____.
The DNA sequences of key
archaebacterial genes are
more like those of
_________ than those of
eubacteria.
Many archaebacteria live in extremely harsh
environments (methogens-thick mud without oxygen,
some live in the Great Salt Lake or in hot springs) 6
Prokaryotes are identified by characteristics such
as shape, the chemical nature of their cell walls,
the way they move, and the way they obtain
energy.
____ (spherical)
______ (rod-shaped)
______ (corkscrew)
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Two different types of cell walls are found in
eubacteria.
A method called _____ stain consists of two
dyes-one violet (the primary stain) and the other
red (the counterstain).
The violet stains peptidoglycan cell walls,
followed by an alcohol wash, that is intended to
wash out the stain.
Gram-_______ bacteria have thicker walls that
retain the dark color.
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Gram-______ bacteria have thinner walls inside and
outer lipid layer.
Alcohol dissolves the lipid and removes the dye from
the walls of the bacteria.
The counterstain makes them appear ____ or light red.
Some prokaryotes do not move at all, while other
propel themselves with _______, a whiplike structure.
Some lash, snake, or spiral forward.
Still others glide slowly on a layer of ________
material they secrete.
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Most prokaryotes get their energy from other
organisms which means they are _________.
Some, however, are autotrophs and make their
own food from inorganic molecules.
_____________ – heterotrophic prokaryotes that
must take in organic molecules that supplies
them with carbon.
_________ – uses sunlight for energy, but they
also need to take in organic compounds as a
carbon source.
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Photoautotrophs - uses ____ energy
to convert CO2 and H2O to C
compounds and O2 in a process
similar to green plants.
Ex. cyanobacteria (bluish pigment)
Chemoautorophs – perform
chemosynthesis, they make organic
C from CO2.
2500 meters deep
Instead of sunlight they use NH3,
H2S, nitrites, S, or Fe
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Hydrothermal vent
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Obligate _____ –
organism that require a
constant supply of O2.
Mycobacterium tuberculosis
Obligate _______ – must live in the
absence of O2.
It can grow in canned food that has
not been properly sterilized.
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Closstridium botulinum
______ anaerobes – do not require O2, but
neither is it _____ by its presence.
Because of the ability to switch between living in
and out of O2, they have the ability to live
almost everywhere.
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____ fission occurs
when a bacterium has
grown to nearly 2X its
size, it then replicates
its DNA and divides
into 2 daughter cells.
It does not require the
exchange of genetic
information, it is an
______ form of
reproduction.
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Hollow bridge
Many bacteria are able to exchange genetic
information by a process called _______.
During conjugation a hollow bridge forms between
two bacterial cells, and genes move from one cell to
the other (increases the genetic diversity).
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When growth conditions are unfavorable, many
bacteria form structures called ______.
An endospore is formed when a bacterium produces a
thick ______ wall that encloses its DNA.
Spores remain _______ while waiting for more
favorable growth conditions.
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Bacteria are vital to maintaining the living world.
Some are producers and capture energy by
photosynthesis.
Others are decomposers that break down the
nutrients in dead matter and the atmosphere.
Still other bacteria have human uses.
18
Every living thing depends
directly or indirectly on a
supply of raw materials.
As decomposers, bacteria help the ecosystem
recycle _______, which maintains an
equilibrium in the environment.
Bacteria breaks down complex compounds into
simpler ones.
19
Plants and bacteria depend on
bacteria for _______.
Nitrogen makes up about ___
of the Earth’s atmosphere.
Plants can not use nitrogen
gas directly, it has to be
changed to the compound
_______ (NH3).
The process of converting nitrogen gas into a form
plants can use is called ________ _____.
This allows N2 to be recycled in nature.
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Many plants have a ______ relationships with
nitrogen fixing bacteria.
Soybeans and other legumes host the bacterium
______.
Rhizombium grows in
______, or knobs, on the
roots of the plant, and
converts __ in the air into
ammonia NH3
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Uses for bacteria:
1.Used in production of foods and beverages.
2.Used in industry.
3.Digest petroleum.
4.Help to mine minerals.
5.Synthesize drugs and chemicals through
genetic engineering.
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VIRUSES
OBJECTIVES: 19.2
Describe the structure of a virus.
Explain how viruses cause infection.
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_____ are particles of nucleic acid, protein, and
in some cases, lipids.
Viruses can only reproduce only by ______
living cells.
All viruses no matter the size have one thing in
common: They enter living cells and, one inside,
use the machinery of the infected cell to produce
more viruses.
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A typical virus is composed of a core of ___ or
____ surrounded by a protein coat.
A virus’s protein coat is called
its _____, it has proteins that
allows a virus to enter a host
cell.
Most viruses are highly
______ only being able to
bond to certain sites.
T4 bacteriophage
Viruses that infect bacteria are
called ___________.
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In a ____ infection, a cell
enters a cell makes copies
of itself, and causes the
cell to burst.
Because the host cell is
lysed and destroyed, this
process is called a lytic
infection.
Other viruses, including the bacteriophage
lamda, causes ______ infections in which the
host cell makes copies fo the virus indefinitely.
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In a lysogenic infection, a virus integrates its
DNA in the DNA of the ____ cell, and the viral
genetic information replicates along with the
host cell’s DNA.
The viral DNA is embedded in the host’s DNA is
a ______.
The prophage may remain part of the DNA of
the host cell for many generations before
becoming active.
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Some types of cancer
Aids
Some viruses contain RNA as their genetic information
and are called ________.
When they infect a cell, they produce a DNA copy of
their RNA, it is then inserted into the DNA of the host
cell.
Retroviruses get their name because their genetic
information is copied _______ from RNA to DNA
(retro means backward).
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DISEASES CAUSED BY BACTERIA AND
VIRUSES.
OBJECTIVES: 19.3
Explain how bacteria cause disease.
Describe how bacteria growth can be controlled.
Explain how viruses cause disease.
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______ are disease-causing agents.
All bacteria need nutrients and energy; however,
disease results when bacteria interfere with the
host’s ability to obtain enough of those elements.
Many bacteria live on and within our bodies, and
some help us perform essential functions,
digesting food.
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Louis Pasteur was the first
person to show convincingly
that _____ cause disease.
He help establish the ____
theory.
Bacteria produce disease in one
of two general way.
Some ____ the cell and tissues of the infected organism
directly by breaking down the cells food.
Some release ____ (poisons) that travel throughout the
body interfering with the normal activity of the host
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Healthy lung
TB lung
Caused by the bacterium Mycobacterium tuberculosis.32
_______ causes strep
throat that release toxins
in to the blood stream.
Strep throat
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Corynebacteria diphtheria,
infects the tissue of the
throat.
________ can lead to breathing problems, heart
failure, parlaysis and death.
34
Many bacterial diseases can be prevented by
stimulating the body’s immune system with
_____.
A ______ is a preparation of weakened or killed
pathogen.
When injected, a vaccine sometimes prompts the
body to produce immunity to the disease.
_________ is the body’s ability to destroy new
pathogens.
35
If a bacterial infection occurs, ______ can be
used to attack and destroy the bacteria.
Antibiotics are compounds that block the growth
and reproduction of bacteria.
Animals are also infected with bacterial diseases,
some also infects humans.
Anthrax
36
There are various methods used to control bacterial
growth, including sterilization, _______, and food
processing.
Sterilization destroys all bacteria by subjecting them
to great ____.
Most bacteria can not survive at ____ temperatures.
Disinfectants are chemical solutions that kill
_________ bacteria.
_____ of antibacterial compounds increases the
likelihood that ordinary bacteria will eventually
evolve to become resistant to them.
37
Bacteria can cause food to ______.
One method of stopping food from spoiling is
storing it in a refrigerator.
_____ temperature keeps food longer.
Cooking techniques raises the temperature of the
food to point where the bacteria is killed.
Like bacteria, viruses produce disease by
disrupting the body’s normal equilibrium.
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Hepatitis A
Small pox
Chicken pox
Measles
Hepatitis C
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Foot and mouth disease
human
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Viruses produce serious animal diseases as well. An
epidemic of foot and mouth disease swept through
Europe in the 1990’s.
Thousands of cattle had to be destroyed in an effort
to control the disease.
The animal viruses, Rous sarcoma virus, causes
______ in chickens.
Viruses also infect plants such as the tobacco
________ virus.
Plant viruses contain a core of nucleic acid and a
protein coat
41
Most plant viruses have a difficult time entering
the cells they infect.
Partly because plant cells are surrounded by
tough cell walls that viruses alone cannot break
down.
They take advantage of ____ or tears on the
plant.
Viruses can be spread by _____, because the
feeding action causes and opening for the virus
to enter.
42
Scientists have discovered two other viruslike
particles that causes diseases.
1.____ causes disease in plants.
They are single-stranded RNA molecules and
has no surrounding capsid.
They enter the cell and direct the synthesis of
new viroids.
They then disrupt the metabolism of the cell
and stunt the growth of the entire plant.
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2. _____ is short for “protein infectious particles
Prions causes diseases by forming protein
clumps.
These clumps cause other proteins to become
prions.
Eventually, there so many prions in the nerve
tissue that cells become damaged.
Mad cow and Creutzfeldt-Jakob disease may be
caused by prions.
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