Ch. 4: Prokaryotic cells Flashcards
Mycoplasmas lack a ____________
cell wall
Which of the three domains includes organisms that would be most likely to survive the environmental conditions that existed on Earth nearly 4 billion years ago?
Archaea
The outcome of the Gram stain is based on differences in the __________________
cell wall.
Bacterial flagella are made primarily of:
flagellin
The transfer of genes during bacterial conjugation involves rigid, tubular appendages called __________
pili.
A bacterial cell exhibiting chemotaxis probably has
flagella.
Spirochetes have a twisting and flexing locomotion due to appendages called
periplasmic flagella (axial filaments).
___________ do not have the typical peptidoglycan structure found in bacterial cell walls.
Archaea
A prokaryotic cell wall with small amounts of teichoic acid and lipoteichoic acid is gram _________
POSITIVE
Peptidoglycan is a unique macromolecule found in bacterial ________________
cell walls.
periplasmic space
the space between the plasma membrane and the cell wall.
Lipopolysaccharide is an important outer membrane component of
_______________________________
gram-negative bacteria.
What unit of measure is most appropriate for expressing the size of bacteria?
micrometer
Prokaryotes have been around for roughly:
4 billion years
Which cell structure is an important component in modern genetic engineering techniques?
plasmids
Bacterial endospores are not produced by
Staphylococcus
Tetrads are comprised of:
cocci
Staphylococcus refers to:
spherical cells in clusters
The small subunit of the prokaryotic ribosome is called ____________.
30S
The most immediate result of destruction of a cell’s ribosomes would be
protein synthesis would stop.
Describe the major structures of all bacteria
-cell (cytoplasmic) membrane: thin sheet of lipid and protein that surrounds cytoplasm
-bacterial chromosome or nucleoid: condensed
DNA molecules; contains genetic info and codes for all proteins
-ribosomes; protein synthesis sites
-cytoplasm: water-based solution filling the cell
Differentiate between eukaryotic and prokaryotic cells.
-Eukaryotic cells found in animals, plants, fungi
-have organelles.
-prokaryotic cells only in bacteria and archaea
-do not have organelles or true nucleus
What are the major cell extensions of prokaryotic cells?
Flagella
periplasmic flagella AKA axial filaments
Fimbriae
Pili
S Layer
Glycocalyx: Slime layer & capsule
Biofilm
What are the 2 separate functions of cell extensions of prokayoritic cells?
Swimming or attachment
(prokaryotic) flagella
-bacterial motility/propellers.
-spin counter clockwise, propel bacteria through liquid.
-Very thin, can’t see without electron microscope. -Has filament made of flagellin.
-Can differ in number and arrangement.
-bacterial swimming - runs or tumbles. Run- from point A to B. Tumbling- somersaulting in space.
Periplasmic flagella AKA axial filaments
2+ long coiled threads only in spirochete bacteria
-wrap around cell
-bend, twist, flex
Fimbriae
small, bristle-like fibers emerging from the surface of many bacterial cells.
-Stick to each other and surfaces.
-provides adhesion, not locomotion
pili
and what is it made of?
-in gram-negative bacteria
-made of protein pilin.
-Help cells stick to things; DNA exchange during bacterial conjugation.
-Can send some genes through pili to another cell.
S Layer
protective layer made of single protein for protection.
Glycocalyx composition, function & 2 types
-made of many polysaccharides
-Function: protect (from dehydration), attachment to surfaces, coat cells
—2 types
1) Slime layer: loose water shield, can be easily washed off
2) Capsule: thicker, bound tightly to cell, protect from dehydration and phagocytosis
Biofilm
slimy layers of microorganisms that stick to each other and wet surfaces.
-They may cause up to 80 percent of infections.
Gram + VS Gram - Cell Envelopes
Gram Positive
-many thick layers of peptidoglycan cell wall
-lack an outer membrane
-has lipoteichoic and teichoic acid which increases wall flexibility
Gram Negative
-thin peptidoglycan cell wall
-has outer membrane with lipopolysaccharide
-has porin proteins
inclusion bodies
-aggregated proteins; storage bodies (sugars, nutrients, gases…).
-Membrane-bound Not an organelle.
What are the major internal components of the prokaryotic cell?
Nucleoid
Bacterial chromosome
Plasmids
Inclusion bodies
Granules
Bacterial cytoskeleton (not all)
Ribosomes
chemotaxis
tendency of cells to move in response to a chemical gradient (Toward attractant or to avoid an adverse stimuli)
cell membrane
thin sheet of lipids and proteins that surround cytoplasm and control flow of materials in and out of cell
cell wall
outer covering of the cell
lysis
physical rupture or deterioration of a cell
nucleoid
region in prokaryotic cell with the most genetic material
plasmids
small, double-stranded DNA molecule containing extra genes
endospore
[what is it?
name some examples]
small, dormant, resistant derivative of a bacterial cell that germinates under favorable growth conditions into a vegetative cell
-more so a life stage
ex)
Clostridiodes difficile: diarrhea, paralyzes you
Clostridium botulinum- toxin
Clostridium tetani- tetanus, can’t relax muscle
Clostridium perfringens (happend in war from bullets)
coccus
spherical shaped bacterial cells
(diplo-, tetrad, strepto-, and staphylo-)
bacillus
rod-shaped/ cylindrical cell shape
spirillum
has a rigid spiral shape and external flagella
-only 2-3 rotations; rotate like a corkscrew
spirochete
a coiled, spiral-shaped bacterium with endo flagella; axial filaments AKA periplasmic flagella wrapped around the cell.
-bends/flexes as it moves
-have 6-12 twists
bacterial cytoskeleton
(not in all bacteria)
-stabilize cell shape, help cell division, cell and molecule motility.
-Made of actin filaments.
Ribosomes and 3 types
protein synthesis.
-If actively synthesizing proteins, it is 70S. (Both units together).
-large subunit is 50S.
-small subunit is 30S.
vibrio
curve/comma shape
-obligate intracellular parasites:
2 examples?
rely on 3d organism as a carrier
-Rickettsia (rocky mountain spotted fever) & chlamydia.
2 types of photosynthetic bacteria
-cyanobacteria; photosynthesis, can produce oxygen; blue-green algae. Help break down rock to soil for other organisms ; important ; still around today
-fossils: stromatolites
Purple sulfur bacteria:
use sulfur for metabolism; capable of photosynthesis
Myxobacterium:
gliding bacteria that can form fruiting bodies
-Occur in soil.
Halophiles:
and their cell wall?
cell wall may be made of polysaccharides or proteins, or missing (not made of peptidoglycan)
-extreme environments not for human life (salt loving, like in salt ponds)
Thermophiles
grows best at very high temp. Live in underwater volcanos
methanogens:
make or generate methane
-live in swamps, lakes, oceans, digestive tracts of cows, trap heat in atmosphere, climate change.
-Mainly added thru cow burps.
[also, may be on mars]
Which domain are these:
protozoa, algae, slime molds, animals, fungi
Eukarya
Which domain are these:
crenarchaeota, nanoarchaeota, euryacheota
Archaea
Which domain are these:
spirochaetes, planctomycetes, chlamydiae, cyanobacteria, chlorobi, bacteriocytes, proteobacteria, firmicutes, actinobacteria, aquificae, thermotogae
bacteria
the first life on earth 4 billion years ago lived where?
deep in the ocean near sulfur geothermal ocean vents (underwater volcanoes deep in the ocean)
[today, archaea live there]
