Flashcards in MicroBio Q's TF CH3 Deck (53):
In what way are bacterial and archaeal cells similar?
In cellular organization
How are bacterial cells that grow in irregular groups and divide in random planes are characterized as what?
Which characteristics contribute to variation in bacterial and archaeal size and shape?
Surface area-to-volume ratio, presence of filamentous structures, and cytoskeletal elements
Describe the layers of bacterial cellular organization (starting internally and working outward)
Cytoplasm, plasma membrane, cell wall, and capsule
What is the purpose of the nucleoid in bacterial and archaeal cells?
Localization of genetic material
What is the function of the plasma membrane in bacterial cells?
To detect and respond to chemicals in the surrounding environment, to provide a selectively permeable barrier, and to facilitate important metabolic processes
How would you best describe the current understanding of the fluid mosaic model of membrane structure?
Phospholipid bilayer with peripheral and integral membrane proteins
Why are hopanoids important to bacterial cells?
Because they likely provide membrane stability
How would you best describe the bacterial cell wall?
It protects the cell from osmotic lysis, contributes to pathogenicity, and site of action of several antibiotics
Most gram-positive bacterial cells exhibit which characteristics?
Thick layer of peptidoglycan with teichoic acids and small periplasmic space
Most gram-negative bacterial cells exhibit which characteristics?
Thin layer of peptidoglycan without teichoic acids, large periplasmic space, and outer membrane
What is the function of lipopolysaccharides (LPSs) on gram-negative bacterial cells?
To assist in evading the host immune response, to contribute to the negative charge on the cell surface, and to create a permeability barrier
Why do gram-positive cells stain purple?
Because ethanol shrinks the peptidoglycan pores and prevents loss of crystal violet
If bacterial cells treated with lysozyme are placed into a hypotonic solution, what would be the result?
The cells would likely swell and lyse
How do slime layers assist bacterial cells?
By facilitating motility
What is a unique feature of archaeal cell s-layers?
They are located just outside the plasma membrane
Why are archaeal membrane lipids unique?
Because they contain branched hydrocarbons derived from isoprene units, they are attached to glycerol by ether links, and they are often composed of C20 diethers and C40 tetraethers
What is the best way to describe the most common archaeal cell wall?
S-layer composed of glycoproteins or proteins
How would you best describe the function of the bacterial cytoskeleton?
It facilitates cell division, localizes proteins to certain sites in the cell, and determines cell shape
What is the function of ribosome in the bacterial cell?
To synthesize proteins
Give a true statement regarding plasmids
The replicate autonomously
What is the name of a bacterial cell with flagella spread evenly over the whole surface?
What is the primary function of bacterial flagella?
How do archaeal flagella differ from bacterial flagella?
They are thinner than bacterial flagella, they are composed of multiple subunit types, and their flagellum is solid instead of hollow
What is flagellar movement driven by?
Which bacterial movements are type IV pili associated with?
What allows for bacterial cells to sense a chemical gradient and respond appropriately?
What is a true statement regarding bacterial endospores?
Endospores survive in nutrient limited conditions
Which structure of the endospore contributes to its resistance to heat and other lethal agents?
The exporium and spore coat, the inner membrane, and the core
What has viviparity been observed in?
Pleomorphic cells are variable in shape and lack a single, characteristic form
Larger cells have a greater surface area-to-volume ratio
Bacterial and arachaeal cells share a common cell organization
Peripheral proteins in the plasma membrane are easily removed and comprise up to 30% of membrane proteins
Scientists agree upon all aspects of the fluid mosaic model
At higher temperatures, bacterial phospholipids have more saturated fatty acids
Hopanoids in bacterial cell membranes contribute significantly to the world's petroleum formation
Peptidoglycan is common to both gram-positive and gram-negative bacterial cells
Periplasmic space comprises a larger portion (20-40%) of the gram-positive cell wall
The component of lipopolysaccharides (LPSs), lipid A, elicits an immune response by an infected host
In the gram staining preocedure, iodine is used to promote dye retention
Capsules are layers outside the cell wall that are well organize and not easily washed off
S-layers are currently being studies for their potential use in the field of nanotechnology
Archaeal membrane lipids are capable of forming pentacyclic rings
Archaeal cell walls have the same chemical composition as bacterial cell walls
Eukaryotic and bacterial cytoskeletons have analogous components
Polyphosphate granules store phosphate in bacterial cells living in nutrient-limited conditions
Archaeal and bacterial ribosomes have the same make up and size
All bacteria have one circular chromosome
Bacteria cells can lose plasmids spontaneously
Type IV pili are involved in bacterial motility and uptake of DNA during transformation
Chemotaxis is best described as random, aimless movement in bacteria and archaea