Chapter 4 Flashcards
Monomorphic vs pleomorphic
Monomorphic: Single shaped
Pleomorphic: Many shapes
Average size of bacterial cell: ___ to ___ µm diameter, _ to _ µm length
0.2 to 2.0 µm diameter, 2 to 8 µm length
T/F Most bacteria are pleomorphic
FALSE, most are monomorphic
What are capsules made of?
sugars, polysaccharides
-Capsule and Slime layers
-External to cell wall
– Many bacteria produce it, but not all
-Viscous, gelatinous, sticky
Glycocalyx
_________: neatly organized, tightly attached, tight matrix; visible if treated with India ink
________: unorganized, loosely attached,
easily deformed
capsule
slime layer
What are the 3 functions of glycocalyx?
–attachment to surfaces
– Prevents dehydration/dessication
– virulence
What do capsules protect cells from?
- phagocytosis (eating) by immune cells
- help microbes adhere to body surfaces (attachment)
– Bacillus anthracis
– Streptococcus pneumoniae
– Klebsiella pneumoniae
what structure assists swimming in Bacteria (Archaella in
Archaea)?
flagella
Extracellular polymeric substance helps form what?
biofilms
Function of biofilms
Protects cells, helps microbes attach to surfaces
– Streptococcus mutans
– Vibrio cholerae
Bacteria Morphology
Bacillus
▪ Coccus
▪ Spiral
– Vibrio
– Spirillum
– Spirochete
▪ Star-shaped
▪ Rectangular
These are characteristics of what?
– long, thin appendages (15–20
nm wide) anchored in cell at
one end
– tiny rotating machines that push
or pull through liquid
– Use propeller-like movements to push bacteria
flagella
What are the 3 basic parts of flagellum structure?
Filament, hook, basal body
The speed of flagella increases or decreases depending on what?
proton motive force
What are the flagellar arrangements?
monotrichous: flagelli on one end
amphitrichous: flagelli on both ends
lophotrichous: flagelli grouped on one end
peritrichous: flagelli all over cell
Axial filaments are also called ______
endoflagella
Flagella allow bacteria to move toward or away from ______ (taxis)
stimuli
Some flagella are important in bacterial __________, e.g. H. pylori penetration through mucous coat?
pathogenesis
some flagella proteins are what and distinguish among serovars (e.g., Escherichia coli O157:H7?
H antigens
fimbrae are hairlike appendages that
allow for what? They are involved in the formation of?
-allow for attachment
-involved in formation of biolfilms
Where are axial filaments found?
Found in spirochetes
- Treponema pallidum (Syphilis);
- Borrelia burgdoferi (Lyme disease)
Rigid structure that:
* Surrounds cytoplasmic membrane
* Determines the shape of bacteria
* Prevents cell from bursting
(Osmotic lysis
bacterial cell wall
Rigidity of bacterial cell wall is due to
peptidoglycan (PTG)
- only in bacterial cell wall
T or F peptidoglycan has a common chemical structure?
false, it has a UNIQUE chemical structure
that distinguishes Gram- positive from Gram-negative
What domains are peptidoglycan (PTG) found in?
found only in bacteria
Basic structure of peptidoglycan ( 2 sugars)
- N-acetylglucosamine (NAG)
- N-acetylmuramic acid (NAM)
How is Peptidoglycan stabilized?
horizontal / vertical cross- links containing peptide interbridges
1._________interferes with the formation of the peptide cross-bridges that link the peptidoglycan rows, weakening the 2._______ _____
- Penicillin
- Cell wall
What is the structure of the gram-negative cell wall?
PTG is between outer
membrane and cytoplasmic
membrane
Gram positive cells all commonly have what acid that gives cell what type of charge?
teichoic acids
negative charge
T/F The outer membrane of gram-negative cell is impermeable to many things
TRUE
Transmembrane protein channels for entrance and exit of solutes
Porins
lipoteichoic acids and teichoic acids are _________ bound to
membrane lipids
covalently
What are the 3 representative genera of Gram+?
- Bacillus
- staphylococcus
- streptococcus
what is LPS: Gram-negative outer
leaflet membrane made of?
lipopolysaccharides not phospholipids
What are the 3 representative genera of Gram-?
- Escherichia
- Neisseria
- Pseudomonas
2 Medically significant portions of LPS
- O-specific polysaccharide side chain
- Lipid A
LPS (lipopolysaccharides) serves as barrier to what?
large number of molecules
Why is the O-specific polysaccharide side chain important?
Used to identify certain species or strains (E. coli refers to specific O-side chain)
Portion that anchors LPS molecule in lipid
bilayer
lipid A
Lack peptidoglycan
– Typically lack outer membrane
– Most lack polysaccharide wall, instead have S-layer
(protein shell)
Which cell wall is described above?
Archaeal cell wall
Lipid A is a toxic __________ and can cause pain, fever, and damage to blood vessels
endotoxin
What destroys peptidoglycan (PTG) that is
found in human secretions and has major defense against bacterial infection?
lysozyme
(cleaves glycosidic bond between sugars)
In methanogens, which cell wall is similar to peptidoglycan?
pseudomurein
Archaeal cell wall cannot be destroyed by what?
lysozyme and penicillin
Penicillin blocks the formation of what?
peptide bridges in peptidoglycan
Why are Gram- bacteria not susceptible to penicillin like Gram+ bacteria?
Outer membrane of Gram-negative cell wall blocks access of penicillin
Which atypical cell wall is described below?
– Lack cell walls
– Sterols in plasma membrane may protect cell from lysis
– Cause mild pneumonia
Mycoplasmas
acid-fast, mycoplasmas, and archaea all have what in common?
atypical cell walls
-Similar to Gram-positive cell walls (thick peptidoglycan)
– Waxy lipid (mycolic acid) bound to peptidoglycan
– Stain with carbolfuchsin
– Carbolfuchsin is not removed when rinsed with acid alcohol
acid-fast cell walls
Which atypical cell wall is described below?
- Walls of pseudomurein (lack NAM and D-amino acids)
Archaea
what are the two Acid-fast genera?
– Mycobacterium
– Nocardi
Why is the external structure so important?
- Many antibiotics target the cell wall
-An outer membrane complicates treatment with antibiotics - allow for attachment to certain surfaces and gives structure
Define Plasma membrane
Surrounds cytoplasm and separates the cytoplasm from environment
What do Bacterial and eukaryotic cytoplasmic membranes have in common?
phospholipid bilayer
containing embedded proteins.
What is the main function of the plasma membrane?
selective permeability (nutrients
transported in and waste products out)
What do membrane proteins do in the plasma membrane?
facilitate reactions and
function in energy metabolism
What do phospholipids contain?
- hydrophobic (water-repelling) components
- hydrophilic (water-attracting) components
Each phospholipid contains what 2 things?
hydrophilic phosphate head and
hydrophobic fatty acid tail
T or F Proteins are not
stationary and are constantly changing position for various function hence the fluid mosaic model?
True
hydrophilic (head) = _______ + _________ and another
functional group
hydrophilic (head) = glycerol + phosphate and another
functional group
hydrophobic (tails) = ______ _____
Fatty acids
Membrane is embedded with numerous what that can function as receptors, transport gates, a mechanism to sense surroundings, etc?
proteins
______________: are on the inner or outer surface of the plasma membrane and loosely attached
___________: integral membrane proteins
____________: extend completely across
membrane
peripheral membrane
proteins
embedded proteins
Transmembrane proteins
T or F the Cytoplasmic membrane is permeable to anything?
False, it is “selectively permeable”
What are the 3 major functions of the plasma membrane?
- permeability barrier
- protein anchor
- energy conservation
_____________: substances move from high concentration to low concentration; no energy
expended
____________: substances move from low concentration to high concentration; energy
expended
Passive Transport
Active Transport
Energy conservation and consumption (METABOLISM) helps with what?
- proton motive force (PMF)
- enzymes for ATP production
protein anchor does what?
Holds proteins in place.
Archaeal cytoplasmic membranes have
what type of linkages in phospholipids of Archaea?
– Ether linkages
Simple diffusion, facilitated diffusion, and osmosis are all examples of which type of transport?
Passive Transport
Define facilitated diffusion
Movement of ions or larger
molecules across the membrane.
- move WITH concetration gradient
Bacteria and Eukarya have what type of linkages in phospholipids?
ester linkages
Archaeal lipids have what instead of fatty
acids?
isoprenes instead
movement of a solute from an area of high
concentration to an area of low concentration until evenly distributed
Simple diffusion
In osmosis:
more water =
less water=
more water = less solute
less water= more solute
the net movement of water across
a selectively permeable membrane
from an area of higher water
concentration (lower solute
concentration) to an area of lower
water concentration (higher solute
concentration)
osmosis
Inflow of water exerts osmotic pressure on membrane. Membrane rupture is prevented by?
rigid cell wall of bacteria
Match the word with the definition: hypotonic, hypertonic, isotonic
- __________: solute concentrations inside
and outside of cell is same; water is at equilibrium– No net movement of water - ___________: solute concentration is lower
outside than inside the cell; water moves into cell - ___________: solute concentration is
higher outside of cell than inside; water moves out of cell
- Isotonic: solute concentrations inside
and outside of cell is same; water is at equilibrium– No net movement of water - Hypotonic: solute concentration is lower
outside than inside the cell; water moves into cell - Hypertonic: solute concentration is
higher outside of cell than inside; water moves out of cell
The thick, aqueous, elastic, semitransparent substance
inside the plasma membrane
Cytoplasm
Some disinfectants damage the plasma
membrane what are they?
– Alcohols
– Quaternary ammonium compounds
(detergents)
Some antibiotics damage the plasma membrane name one?
– Polymyxin
What is the cytoplasm made of?
Eighty percent water plus proteins, carbohydrates, lipids,
and ions
Damage to plasma membrane causes what?
leakage of cell contents
T/F Cytoplasm has DNA (nucleoid), ribosomes, and inclusions
TRUE
which bacterial cell internal structures are essential for life?
– Chromosome
– Ribosome
- cell wall and membrane (but these are outer structures)
The cytoskeleton in the cytoplasm functions in what 4 things?
– Cell division
– Maintaining cell shape
– Growth
– DNA movement
Internal structures of Bacterial Chromosome/Nucleoid
- where is it?
- how many chromosomes?
- shape?
- does it contain all genetic
information? (Y/N) - Does it have a membrane and proteins?
- cytoplasm
- single chromosome
- Circular, double-stranded
molecule - YES
- NO membrane and proteins
what internal structures are optional and can confer selective advantage?
– Plasmid
– Storage granules
– Endospores
name the internal structure?
– small extrachromosomal
circles of DNA
* Generally 0.1% to 10% the size
of a chromosome (5-100 genes)
– Outside of the chromosome
* Independently replicating
– Encode characteristic
plasmids
what are potential enhances of survival in plasmids even though they are not necessary for life?
– Antimicrobial resistance
– Production of toxins
When the vegetative cell differentiates to a nongrowing,
heat-resistant, light-refractive structure what is it called?
Endorspore sporulation
In which 2 cells and cell structure are ribosomes present?
Prokaryotes, eukaryotes, and cytoplasm
What is the function of ribosomes?
protein synthesis
What are ribosomes made of?
Made of protein and ribosomal RNA
* (Prokaryotic) 70S:
* Eukaryotic 50S large + 30S small subunits
What are the three steps in germination?
activation, germination, and outgrowth
Specialized spores that are resistant to desiccation, heat, radiation, chemicals
endospores
this is considered what type of mechanism?
Vegetative → Endospore → Vegetative
A survival mechanism; not a reproductive process
- __________: endospore formation
- ___________: endospore returns to vegetative state
sporulation
germination
endospores are ideal for dispersal via?
wind, water, or animal gut
endospores are produced by members of what bacteria?
Bacillus and Clostridium (Gram-positive)
What is germination triggered by?
Nutrient availability
What special stain is used for germination?
malachite green
*Bacteria in vegetative state
sense ______ and begin
sporulation.
*Vegetative cell will
___ while the spore
remains
* Spore will go back
to vegetative cell
when ________
___________ return
starvation
die
favorable conditions
Eukaryotic plasma membrane is similar in chemical structure and function of cytoplasmic membrane of prokaryote in what way?
Phospholipid bilayer embedded with proteins
__________: Spore is at the end of the bacteria
__________: Spore is towards the end but not fully
__________: Spore is centered
Terminal
Subterminal
Central
Eukaryotic plasma Membrane contains _________ for strength
* Animal cells contain _________
* Fungal cells contain ________
sterols
cholesterol
ergosterol
what are the difference in sterols?
target for antifungal medications
– Nucleus
– Ribosomes
– Endoplasmic
reticulum
– Golgi apparatus
– Lysosome and
vacuoles
– Mitochondria and
chloroplasts
– Peroxisomes
– microtubules, and
microfilaments.
– Flagella and cilia
In eukaryotic cells all of these are membrane bound? (T/f)
False, all are membrane bound except
– microtubules, and
microfilaments.
– Flagella and cilia
DNA molecules are wrapped around proteins to form fibers called what?
Archaea also contain histones and nucleosomes; related to
__________?
chromatin / nucleosomes
eukarya
What is the chemical structure of the plasma membrane?
Phospholipid bilayer
what is produced in the nucleolus?
ribosomes
Each very long chromatin fiber twists and folds to form a condensed ___________?
chromosome
Define nucleus
Double membrane structure (nuclear envelope) that
encloses the cell’s DNA
what forms the folds of the mitochondrion?
cristae
when one species lives inside another host
species (think of “Pac Man”
endosymbiosis
which 2 organelles specialize in energy metabolism and have an endosymbiotic origin?
mitochondria and chloroplasts
The nucleus is enclosed by what two membranes?
nucleoplasm
(inner membrane) and cytoplasm (outer membrane)
DNA is complexed with ________ proteins to form
________ / __________
histone
chromatin
nucleosomes
the individual disks in chloroplasts are called what?
thylakoids
where do light reactions occur in the chloroplasts?
thylakoids
What happens to chromatin during mitosis and meiosis?
it condenses into chromosomes
Mitochondria and chloroplasts contain circular DNA _______ and ________ (70S) similar to those of ________
genomes and ribosomes (70S) similar to those of Bacteria
The nucleus contains a
darker area called a
_____________
nucleolus
Mitochondria and chloroplasts are the only 2 organelles that have their own ____ and replication?
DNA
A particular location within
the nucleus where ribosomes are made
Nucleolus
DNA > RNA
RNA > DNA
Transcription
Translation
What 2 things occur inside of the mitochondria?
cellular respiration and oxidative
phosphorylation for aerobic eukaryotes
Oxidative Phosphorylation uses _______ to harvest ________(ATP) from sugar molecule
oxygen
energy (ATP)
________: folded internal membranes
▪ contain enzymes needed for respiration and ______ production
– ________ : innermost area of mitochondrion
▪ contains ______ acid enzymes
Cristae: internal; respiration & ATP
Matrix: citric acid
What is the Energy Currency of Cell?
ATP (Adenosine Tri-Phosphate)
Cloroplasts is a chlorophyll-containing organelle found in what?
Phototrophic eukaryotes and Algae cyanobacteria
Where is the site of photosynthesis (the energy of sunlight in combination with
water and carbon dioxide is used to create molecules of sugar)?
Chloroplasts
In chloroplasts the inner membrane surrounds ____, which contains large amounts of RuBisCO (key enzyme for ________ cycle that converts CO2 organics
stroma
RuBisCO
Calvin Cycle
CO2
__________: flattened membrane discs contain chlorophyll and
ATP synthetic components, form proton motive force
thylakoids
The ____________ and ___________likely originated from endosymbiosis
Mitochondria
chloroplasts
Eukarya are hypothesized to have originated from what type of fusion of archaeal host and mitochondrial endosymbiont?
symbiotic fusion
Define endosymbiosis
when one species lives inside another host species
Rough ER has what that Smooth ER doesn’t??
Rough ER contains attached ribosomes; smooth does
not
name the organelle:
Transport organelle
* Modifies proteins produced by rough ER
* Finishes, sorts, and ships cell products (FedEx of Cell)
* Transports modified proteins via secretory vesicles to the plasma membrane and other regions
Golgi apparatus
what 4 things does the Golgi apparatus produce?
glycoproteins, lipoproteins, glycolipids, and lysosomes
What are the two functions of the smooth ER?
- synthesis of lipids (fats,
steroids, hormones) - carbohydrate metabolism
Flagella and Cilia Projections are used for what?
locomotion or moving substances along the cell surface
What does the Rough ER produce?
glycoproteins and new membrane material
Lysosomes are present in phagocytic cells and contain what 2 things?
digestive enzymes and recycling cell components
- Flagella-long projections; ____ in number
- Cilia-short projections; _________
– Structurally and functionally differ from prokaryotic flagella
Flagella-long projections; few in number
Cilia-short projections; numerous
flagella and cilia are in ___________ cell structures while fimbriae, pili, AND flagella are in __________ (bacteria) cell structures
eukaryotic
prokaryotic
The cytoskeleton is a network of protein fibers that provides what 3 functions?
Cytoskeleton
- mechanical support
2.anchorage - reinforcement
what provides internal structural support in eukaryotic cells?
Cytoskeleton
Microtubules 3 functions
- maintain shape
- facilitate motility
- move chromosomes and organelles
Microtubules are hollow tubes 25 nm in diameter; composed of α- and β-tubulin
and aid in what 3 things?
cell shape
facilitate motility
move chromosomes and organelles
What structure of the cytoskeleton maintain and change cell shape; involved in amoeboid motility
and cell division?
microfilaments
Intermediate filaments maintain and position what?
maintain cell shape and position organelles
What is the size of prokaryotic and eukaryotic cells?
P: 0.2-2.0 µm in diameter
E: 10-100 µm in diameter
microfilaments are 7 nm in diameter; polymers of actin protein aid in what 3 things?
change cell shape
involved in amoeboid motility
cell division
Are membrane bound organelles absent or present in prokaryotic and Eukaryotic cells?
P: Absent
E: Present
intermediate filaments are 8–12 nm in diameter; fibrous keratin proteins maintain what?
cell shape and position organelles
What is the cell wall made of in prokaryotes?
- Peptidoglycan (bacteria)
- Pseudomurein (archaea)
What is the cell wall made of in eukaryotes?
Cellulose & Chitin
What is the number of ribosomes in prokaryotes and eukaryotes?
P: 70s
E: 80s
