Module 2 Test Flashcards
Chapters 4, 5, and 6
Basic cell shapes
Spherical, cubical, cylindrical
Internal contents of cells
Cytoplasm surrounded by a membrane
Eukaryotic cells
Includes animals, plants, fungi, and protists
-Membrane-bound organelles
-Double membrane bound nucleus
Prokaryotic cells
Includes bacteria and archaea
-No nucleus or membrane bound organelles
-Smaller and less complex
Characteristics of life
-Reproduction and heredity
-Growth and development
-Metabolism
-Movement and/or irritability
-Cell support, protection, and storage
-Transport of nutrients and waste
Prokaryotes: Appendages for motility
Flagella and axial filament (periplasmic flagella)
Prokaryotes: Appendages for attachment or channels
Fimbrae and pili
What composes a flagella?
Filament- long, thin, helical structure composed of flagellin
Hook- curved sheath
Basal body- stack of rings firmly anchored in cell wall
Monotrichous flagella
single flagellum at end
Lophotrichous flagella
Small bunches emerging from the same site
Amphitricous flagella
Rare flagella at both ends of cell
Peritrichous flagella
flagella dispersed all over surface of cellP
Phototaxis
light stimuli
Chemotaxis
Chemical stimuli
+ vs - taxis
+=toward/attracted to
-= away/deterred from
Motion in flagella
Counterclockwise- run
Clockwise- tumble
Periplasmic flagella
-Internal flagella enclosed in the space between the outer sheath and cell wall (peptidoglycan)
How do periplasmic flagella produce motility?
By contracting and imparting twisting or flexing motions
Prokaryotes: Fimbriae
Fine, proteinaceous, hairlike bristles emerging from cell surface
Fimbriae Function
Function in adhesion to other cells and surfaces
Prokaryotes: Pili
Rigid, tubular structure made of pilin
Gram-negative cells only
Function of pili
Function to join cells for partial DNA transfer
Conjugation
DNA transfer– send genetic material via channel
Prokaryotes: Glycocalyx
Coating of molecules external to cell wall made of sugars and/or proteins
Prokaryotes: Types of glycocalyx
Slime layer- loosely organized and attached– function in attachment
Capsule- highly organized, tightly attached– function in protectionF
Prokaryotes: Functions of the glycocalyx
-Protect cells from dehydration and nutrient loss
-Inhibit killing by wbc by phagocytosis
-Attachment- formation of biofilms
Prokaryotes: Cell Envelope
-External covering outside cytoplasm (cell wall and cell membrane)
-Maintains cell integrity
Gram-positive bacteria
-Thick cell wall composed primarily of peptidoglycan and cell membrane
-Retain crystal violet, stain purple
Gram-negative bacteria
-Two cell membranes with a small layer of peptidoglycan in between
-Retain safranin, stain red/pink
-More difficult to penetrate (harder to kill)
Chemical components of gram-positive bacteria cell wall
Techoic acid and lipoteichoic acid- function in cell wall maintenance and enlargement during cell division
Chemical components of gram-negative bacteria cell wall
Lipopolysaccharides in the outer membrane- function as receptors to block immune response
-Contain porin proteins in upper layer- regulate molecules entering and leaving cell
Nontypical cell wall of mycobacterium and nocardia
-Gram-positive cell wall structure with lipid mycolic acid
-Pathogenicity and high degree of resistance to certain chemicals and dyes
-Acid-fast stain used for diagnosis
Mycoplasma Cell wall
-No cell wall
Prokaryotes: Cell membrane structure
-Phospholipid bilayer with embedded proteins
-Semipermeable
Functions of phospholipid bilayer
-Energy reactions, nutrient processing, and synthesis
-Passage of nutrients in and discharge of waste
Cytoplasm
70-80% water- solvent for materials used in all cell functions
Nucleoid
No envelope-chromosome, circular, double-stranded DNA
Ribosomes
-Protein synthesis
-Two subunits
-Found in all cells
-Rough ER in eukaryotic cells
Inclusions and granules
Bacterial internal structures
-Intracellular storage bodies
-Cell can use them when environmental sources are depleted
Endospores
Inert, resting cells produce by some G+ genera
Life cycle of endospores
Vegetative cell- metabolically active and growing
Endospore- adverse environment conditions; capable of high resistance and very long-term survival
Sporulation
Formation of endospores
Germination
Return to vegetative growth
Coccus
spherical shaped
Bacillus
Rod shaped
Coccobacillus
Very short and plump shape (football)
Vibrio
Gently curved shape
Spirillum
Helical, comma, twisted rod shape
Spirochete
Spring-like shape
Pleomorphism
variation in cell shape and size within a single species
Bacterial arrangements
arrangements of cells is dependent on pattern of division
Cocci arrangements
-Singles
-Diplococci- in pairs
-Tetrads- groups of four
-Irregular clusters
-Chains- strep
-Cubical packets (sarcina)
Bacilli arrangements
-Diplobacilli
-Chains
-Palisades
How do prokaryotes provide for eukaryotes?
-Recycling carbon and nitrogen
-C fixation
-N fixation
Carbon fixation
converting CO2 to organic C
Nitrogen fixation
covert nitrogen to ammonia
Microbial ecology
study of symbiotic relationships
Community
Prokaryotes live in groups that interact with organisms
Symbiotic relationships
Any interaction between different species that are associated with each other within a community
Mutualism
Both populations benefit
Amensalism
Population A is harmed while population B is unaffected
Commensalism
Population A is benefitted while population B is unaffected
Neutralism
Both populations are unaffected
Parasitism
Population A is benefitted while population B is harmed
Microbiome
all the microorganisms that are associated with a certain organism or environment
Resident microbiota
microorganisms that are always present
Transient microbiota
microorganisms that are only temporarily present- often pathogenic
Classification of prokaryotes
Shapes, staining patterns, and biochemical or physiological differences- more recently added nucleotide sequences in genes
Bergey’s manual of determinative bacteriology
The main source of how to classify bacteria
Archea
-primitive, adapted to extreme habitats, and modes of nutrition (adapt to heat, salt, acid pH, pressure, and atmosphere)
-Unicellular
-More closely related to eukaryotes than bacteria
-Unique membrane lipids and cell walls
-Contain unique genetic sequences in the rRNA
Phylum proteobacteria
-Gram-negative
-Additional cell membrane
-Spirochetes, CFB