Ch 4: Functional Anatomy of Prokaryotic and Eukaryotic Cells Flashcards
How wide is a typical prokaryote?
0.2 - 2 μm
How long is a typical prokaryote?
2 - 8 μm
What is the diameter of a typical Eukaryotic cell?
10-100 μm
Bacillus = ____
Rod-shaped
Coccus = ____
Spherical
Vibrio = _____
Single twist
Spirillum = _____
Thicker spiral, rigid with proper flagella
Spirochete = _____
Thinner spiral with endoflagella (axial filaments)
Stella = ____
Star-shaped
Diplo = _____
Pairs
Staphylo = ____
Grapelike cluster
Strepto = _____
Chains/twisted
What is a glycocalyx? Examples?
General term for a viscous polymer composed of polysaccharides, polypeptides, or both on the cell surface
Ex: capsule & slime layer
What are the differences between a capsule and a slime layer?
Capsule: organized and firmly attached to the cell
Slime layer: unorganized, diffuse, and easily removed
What are some of the functions of a glycocalyx?
- DAttachment to the environment and each other (biofilms)
- Contribute to virulence (capsules mainly)
- Increased resistance to drying and inhibition of nutrient loss
How can capsules contribute to virulence?
Prevent phagocytosis
Facilitate attachment
What capsulated bacteria are resistant to phagocytosis?
- Streptococcus pneumonia*
- Klebsiella pneumonia*
- Bacillus anthracis*
Where does K. pneumonia typically attach itself?
Respiratory tract
Where does Streptococcus mutans typically attach itself?
Teeth
Where does Vibrio cholera typically attach itself?
Small intestine
Label the following flagella types:
Lophotrichous, Amphitrichous, Pertrichous, Monotricous, Atrichous, Cephalotrichous
True or false. Archae flagella are evolutionarily and structurally different from bacterial and eukaryotic flagella.
True
What direction do flagella rotate to move forward?
Counterclockwise
What direction do flagella rotate to tumble?
Clockwise
Taxis- refers to?
Bacterial movement toward or away from a stimulus
Treponema pallidum is a spirohete that causes _____
Syphilis
Borriella burgdorferi is a spirochete responsible for causing _____
Lyme disease
Where are endoflagella located?
Between the cell wall and outer membrane
How do endoflagella function?
Anchored at one pole of the cell and wrapped around
Filament bundles rotate to produce movement of the outer sheath to propel the cell forward in a corkscrew motion
What are the similarities between fimbriae and pili?
Hairlike appendages that are both
- shorter, straighter, and thinner than flagella
- Comprised of pilin arranged helically around a central core
- Present in most gram-negative bacteria
Where do fimbriae typically occur?
At the poles or evenly distributed
What is the role of fimbriae?
Allow bacteria to adhere to each other and to surfaces
How are pili different from fimbriae?
Pili are longer
THere are only one or two pili per cell
What are the functions of pili? (2)
- Bring two cells together to allow for conjugation (sex pili)
- Surface motility (twitching)
In what bacteria are you most likely to observe twitching motility?
- Pseudomonas aeruginosa*
- Neisseria gonorrhoeae*
Some E. coli strains
What is gliding motility?
The ability of certain rod-shaped bacteria to translocate on surfaces without aid of external appendages such as flagella, cilia, or pili
Thought to involve microtubules, but still not well understood
What are the functions of the cell wall in bacteria? (3)
- Determines cell shape
- Prevents osmotic lysis
- Anchors flagella
Peptidoglycan is composed of?
- N-acetylglucosamine (NAG)
- N-acetylmuramic acid (NAM)
Chitin is composed of?
N-acetylglucosamine
Describe the structure of peptidoglycan.
Linear glycan chains (10-65) linked by polypeptide cross-bridges and side chains
What is the mode of action of Penicillin?
Inhibits enzymes that connect cross bridges and side chains in peptidoglycan synthesis
Describe a gram-positive cell wall?
Many layers of peptidoglycan
One cell membrane
Wall Teichoic acid and Lipoteichoic acid
Functions of the teichoic acids
- Provide rigidity
- Due to their negative charge, they sequester cations (Ca2+ and Mg2) for their eventual transport into the cell
- Promote pathogen adherence to host tissues
- Antigenic specificity used to identify gram-positive bacteria
Describe a gram-negative cell wall
Contains only one or a few layers of peptidoglycan bonded to lipoproteins
Bacteria have outer cell membranes
Gram-negative bacteria have a strong negative charge, which is beneficial against _____
Phagocytosis and complementation
The outer membrane of gram-negative cells provides a barrier against ______, but not against _____
Barrier: Antibiotics, lysozymes, etc.
Not against: small metabolites (due to porins)
Are lipopolysaccharides found on gram-positive or gram-negative bacteria?
Gram-negative
What are the three primary parts of the lipopolysaccharide (LPS)
Lipid A
Core polysaccharide
O polysaccharide
Which part of the LPS has the greatest variation and can be used to distinguish species?
O polysaccharide
at least 20 different sugars known
Lipid A can be released from gram-negative bacteria when they die, which then act as _____
Endotoxins
What is the function of the core polysaccharide in LPS?
Contains unusual sugars that provide stability and structural support
Describe an acid-fast cell wall.
Waxy lipid (mycolic acid) bound to peptidoglycan
True or false. Acid-fast cell walls cannot be visualized with a Gram stain
True
Mycoplasma do not have cell walls, rather they have ____ in their plasma membranes
Sterols
Archaea can be wall-less or have walls composed of _______.
Pseudomurein
What are the differences between pseudomurein and peptidoglycan?
- N-acetyltalosaminuric acid instead of NAM
- Cross-links lack D-amino acids
The cell wall of protoplasts can be ______
Entirely removed (i.e. lysozyme digestion of gram-positive cells)
The cell wall of spheroplasts can be _____
only partially removed (i.e. lysozyme digestion of gram-negative cell walls)
What type of bacteria are susceptible to osmotic lysis?
Protoplasts and spheroplasts
What are L-forms?
A different form of a cell that is “cell wall-deficient” but is able to grow as a spheroplast or protoplast
What causes the development of L-forms of bacteria?
- Could be spontaneous
- In response to penicillin or lysozyme
Are mycoplasma considered L-forms?
No. They are not derived from bacteria that normally do have cell walls
What are some functions of the plasma membrane? (3)
- Selectively permeable barrier
- Contain ATP producing enzymes
- Can contain photosynthetic pigments (chromatophores)
Plasmids contain ___ to ____ genes and are associated with ______.
5-100 genes
Plasma membrane proteins
True or false. Plasmid genes are crucial for the survival of a bacterium.
False. Not crucial for survival under normal conditions
How long can endospores remain dormant for?
Thousands of years
True endospores are only found in _____ bacteria
Gram-positive
What makes the gram-negative bacteria Coxiella burnetti significant?
It produces endospore-like body
and cause Q disease
What is sporulation?
Endospore formation
What is germination?
Return to vegetative state
When are vegetative cells triggered to sporulate?
When key nutrients such as carbon or nitrogen sources become scarce or unavailable
Under what conditions will endospore germination occur?
- When more favorable growth conditions are present
- Triggered by heat
- Triggered by small triggering molecules (i.e. alaninie and inosine)
How do prokaryotic and eukaryotic flagella differ in regard to their movement?
Eukaroyotic flagella move in wavelike pattern
Prokaryotic flagella rotate
What are the steps of the formation of spores?
What is asymmetric cell division?
The ratio of a cell to endospores?
1:1 ratio of cells to endospores
Flagella of eukaryotes
9(circumnavigating doublets of microtubules) + 2 two in the middle
Glycocalyx(Eukaryotes)
Extend from cell wall or plasma membrane
Either Strengthen cell surface, Cell adherence, and cell- cell recognition
Metachromatic granules
Phosphate reserves for ATP
Blue stain will look red
Polysaccharide granules
Energy reserves, Hold glycogen and starch
Lipid granules
hold energy
Sulfur granules
Energy source
Carboxysomes
Fix CO2
Gas Vacuoles
Hold air
Magnetosomes
Iron oxide: allow the bacteria to orient itself to geomagnetic fields
Sporulation
Endospore formation
Germination
Return to vegetative stative
Coxiella burnetti
Gram negative bacteria
Causes Q disease
Produces endospore like bodies
Coxiella burnetti
Gram negative bacteria
Causes Q disease
Produces endospore like bodies
Cyctoskeleton
Provide structure and help with transport,
3fibers:
- Microfilaments
- Intermediate filaments
- Microtubules
Nucleolus
No membrane in the nucleus
Uncondensed regions chromosomes regions
Sire of assembly for small and large cytosolic ribosome subunits
ER
Smooth:
Ca+ control, vesicles are forming and going to the Golgi apparatus
Rough:
Entry point for the vesicular pathway
Carbs and phospholipds may be attached protiens
Golgi Complex
Receive transport vesicles from the ER
Move them within the cistern
sends cargo to the plasma membrane, lysosome
Vacuoles
Small in animals, and large in plants functions vary:
- Storage for proteins, sugars and organic acids
- act as degradative compartments
- Store metabolic wastes and poisons
- Take up water and give rigidity to leaves and stems
