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Micro Bio PPT 3

is a prokaryotic cell with a rod shape
a spherical bacterial cell
this type of bacteria can appear in many different shapes
Spiral shaped
comma shaped spiral shaped
helical spiral shaped
last type of
chain of rod bacteria
pair of joined spherical bacteria
group of four spherical bacteria
cluster of spherical bacteria
chain of spherical bacteria
the structure and organization of bacteria are based on
specific processes call need to carry out
the processes cells need to carry out are
sensing/responding to stimuli, compartmentation of metabolism, growth reproduction
bacterial flagella
Are long appendages extending from the cell surface
flagella can be used for
bacterial flagella contain
helical filament, a hook, and a basal body and move in a circular movement
Bacteria exhibit ______, moving up the concentration gradient of a chemical attractant
one flagella
multiple flagella coming out of one end of a bacteria
flagella coming out of both ends of a bacteria
flagella coming out of a bacteria everywhere
Are protein fibers extending from the surface of many bacteria
pili help
attach cells to surfaces, to form biofilms and microcolonies
Some bacterial species have _______, used to transfer genetic material between cells
conjugation pili
is a outer layer of the cell wall
the glycocalyx is an adhering layer of _____ and some times small proteins
A thick glycocalyx bound to the cell is a
A thinner, diffuse layer of polysaccharides is a
slime layer
glycocalyx protects cells from
the environment, and allows them to attach to surfaces
is a tough and protective external shell
the bacterial cell wall
the cell wall of bacteria protect the cell from
the cell wall also helps the cell to
maintain its shape
what helps a bacterial cell aid in water balance
the cell wall
game positive cell walls
have a peptidoglycan structure that allows the stain to get stuck in the cell
gram negative cell walls
have an outer layer over the peptidoglycan layer that is made up of lipopolysaccharide not letting the stain into the cell wall
Cell walls in bacteria contain
Gram-positive bacteria have _____ peptidoglycan cell walls containing teichoic acid
Gram-negative bacteria have
a two-dimensional peptidoglycan layer and no teichoic acid
has an outer membrane, separated from the cell membrane by the periplasmic space
The gram-negative cell wall
The outer membrane of _____ contains proteins called porins that selectively allow small molecules into the periplasmic space
gram negative
peptidoglycan in gram positive cells
is a thick layer
peptidoglycan in gram negative cells
is a thin layer
only _____ contain teichoic acid
gram positive
Only _____ contain a outer membrane, lipopolysaccharides, porin proteins, and periplasmic region
gram negative
The interface between the cell environment and the cell cytoplasm
cell membrane
cell membrane is the fluid layer of
phospholipid and protein
The phospholipid molecules are arranged in a
Hydrophobic fatty acid chains in the phospholipids form a
permeability barrier
cell membranes can aid in
Cell wall synthesis, Energy metabolism, DNA replication, Sensation of stimuli, Molecule transport
_____ substances may disrupt or dissolve the bilayer
Several antibiotics pick on unique target structures and ______ in the membrane, resulting in death through cell lysis.
poke holes
Center of growth and metabolism is
represents a subcompartment containing the chromosome
the chromosome
is usually a closed loop of DNA and protein
DNA contains
the genes (hereditary information)
a complete set of genes is called a
most cells have only one copy of each gene which means
they are haploid and cannot undergo mitosis like eukaryotes
Damage to DNA
inevitable injures or kills the organism
DNA tells the cell
what proteins to make
proteins facilitate
cellular functions
some proteins are
enzymes that catalyze biochemical reactions and vital to metabolism
protein roles
structural, mechanical, cell signaling, immune responses, cell adhesion, cell cycle
plasmids are
Molecules of DNA smaller than the chromosome
Each plasmid is a closed loop, containing
5-100 genes
Plasmids can be transferred between
R plasmids carry
genes for resistance to antibiotics
plasmids can be used
in genetic engineering
There are hundreds of thousands of _____, used for protein synthesis
Inclusion bodies
store nutrients or building blocks for cellular structures
Some aquatic bacteria use _______ to float on the water's surface
gas vesicles
contain crystals of magnetite or greigite, allowing cells to respond to magnetic fields
bacteria can reproduces by
binary fission
when bacteria reproduce the cell
doubles in mass
the DNA then replicates into _____ once the cell has doubled in mass
two strands
cytokinesis is
aninward pinching of the cell membrane and cell wall to separate the cell into two genetically identical cells
binary fission
1) cell elongates/ DNA replicates
2) cell wall and plasmid membrane begin to invaginate
3)cross wall forms two distinct cells
4) cell seperates
Asexual reproduction can also
be preformed by bacteria
The generation (or doubling) time
is the interval of time between successive binary fissions
in pathogens
means a shorter incubation period of
Thisconstantdoublingofthenumbers only occurs as long as nutrients for growth are available during the _____ of growth.
log phase
log phase is
exponential growth stage for bacteria
during the lag phase of bacterial growth
no cell division occurs while bacteria adapt to their new environment (1st stage)
exponential growth of the population occurs
during the logarithmic (log) pahse
Human disease symptoms usually develop during the
log phase
When reproductive and death rates equalize,
the population enters the stationary phase
The accumulation of waste products and scarcity of resources causes
the population to enter the decline (exponential death) phase
Endospores are
a highly resistant survival structure formed by species of Bacillus and Clostridium when nutrient supplies are low
spores can lay dormant
for years then germinate into a vegetative cell, withstand boiling water, alcohol and radiation
Sporulation cycle
1) bacteria replicate with 2 chromosomes present waiting for split
2)one chromosome necondenses at the end of the cell and a transverse septum separates the prespore from the mother cell
3)septum forms completely and the prespore is completely engulfed in the mother spore
4) outer layer (cortex) develops around the prespore
5) walls of spore are complete and mother cell begins to disintegrate
6) spore is released and will germinate if in present conditions once again
Step 1 of endospore creation
A stressed cell undergoes asymmetrical cell division, creating a small prespore and larger mother cell
the pre spore contains
Cytoplasm, DNA, dipicolinic acid, which stabilizes proteins and DNA
step 2 of endospore creation
Themothercellmaturesthepresporeintoanendospore,then disintegrates, freeing the spore
endospore are resistant to
desiccation, heat, and undergo very few chemical reactions
When environmental conditions are again favorable,
protective layers break down and the spore germinates into a vegetative cell
in order for bacterial to grow
Water, Carbon/energy sources, Essential elements and organic growth factors, Temperature, pH, Oxygen, Carbon dioxide, Osmotic conditions
all nutrients must be
dissolved in water to enter the cell.
Almost ______ of the cell is water.
All cellular chemical reactions occur in
Drying therefore inhibits the
growth of organisms
capsules provide
some resistance to drying as moisture is trapped around the cell.
producing spores is
the ultimate way to survive drying.
use light as primary energy source
reactions of inorganic or organic compounds for energy
use carbon dioxide as carbon source
organic carbon source
Processes of Energy Usage
Biosynthesis of Polysaccharides, Lipids, Amino Acids, Proteins, Purine & Pyrimidine
Essential Elements & Organic Growth Factors
Glucose, salts, carbon, nitrogen, amino acids, purines, pyrimidines, vitamins
Each bacterial species has an optimal temperature for growth and about a ___ range of acceptable temperatures
30 degree
grow optimally below 15°C, and make up the largest portion of all prokaryotes on Earth
multiply best around 60°C, living in compost heaps and hot springs
grow optimally above 80°C, found in seafloor hot-water vents
thrive at the medium temperature range of 10° to 45°C, including pathogens that thrive in the human body
obligate aerobes
require oxygen to grow
prefer O2 slightly lower than air
do not or cannot use oxygen
species are insensitive to oxygen but can grow in its presence
Obligate anaerobes
are inhibited or killed by oxygen
prokaryotes grow either with oxygen or in reduced oxygen environments
bacteria require an atmosphere low in oxygen and rich in carbon dioxide (CO2)
The majority of species grow optimally at
neutral (~7.0) pH
acidophiles are
acid-tolerant prokaryotes, those used to turn milk into buttermilk, sour cream, and yogurt
can withstand incredibly high hydrostatic pressure, psychrophiles living at the bottom of the ocean
are salt-tolerant prokaryotes, They can maintain optimal osmotic pressure without
suffering from plasmolysis
like high osmotic conditions regardless of salt or sugar.