Chp 4 Flashcards
comes from the Greek words for prenucleus.
Prokaryote
comes from the Greek words for true nucleus.
Eukaryote
Prokaryote
have what kind of chromosomes
one circular chromosome not in a membrane
eukaryote have what kind of chromosome
paired chromosome in nuclear membrane
what cells have no histones
prokaryotes
what cells have no organelles
prokaryotes
what cells have bacteria and peptidoglycan cell walls
prokaryotes
what cells are archaea and have pseudomurein cell walls
prokaryote
what cell divides by mitosis
eukaryotes
what cells divide by mitosis
eukaryote
What is the main feature that distinguishes prokaryotes from eukaryotes?
eukaryotes have a true nucleus and prokaryotes have a prenucleus
Most bacteria are what shape
monomorphic (single shape)
a few bacteria are what shape
A few are pleomorphic (many shapes)
Average size of bacteria cells
0.2 to 2.0 µm diameter × 2 to 8 µm length
shapes of bacteria
1) Bacillus (rod-shaped)
2) Coccus (spherical)
3) Spiral
- Vibrio
- Spirillum
- Spirochete
4) Star-shaped
5) Rectangular
arrangement of bacteria
1) Pairs: diplococci, diplobacilli
2) Clusters: staphylococci
3) Chains: streptococci, streptobacilli
4) Groups of four: tetrads
5) Cubelike groups of eight: sarcinae
Pairs of bacteria cell are called
diplococci, diplobacilli
clusters of bacteria cells are called
staphylococci
Chains of bacteria are called
streptococci, streptobacilli
groups of four bacteria are called
tetrads
Cubelike groups of eight bacteria are called
sarcinae
How can you identify streptococci with a microscope?
because its in a chain
Glycocalyx are found where
External to the cell wall
the matter of Glycocalyx is
Viscous and gelatinous
Glycocalyx is made of
polysaccharide and/or polypeptide
what are the types of Glycocalyx
1) Capsule: neatly organized and firmly attached
2) Slime layer: unorganized and loose
Glycocalyx contribute to
virulence
glycocalyx Capsules prevent
phagocytosis
Glycocalyx Extracellular polymeric substance helps
form bio films
the Cause of Pneumococcal Pneumonia
Streptococcus Pneumoniae
Flagella are and do what
- Filamentous appendages external of the cell
- Propel bacteria
- Made of protein flagellin
Flagella are made up of three parts
1) Filament: outermost region
2) Hook: attaches to the filament
3) Basal body: consists of rod and pairs of rings; anchors flagellum to the cell wall and membrane
Flagella allow bacteria to
move toward or away from stimuli (taxis)
Flagella rotate to
“run” or “tumble”
Flagella proteins are
H antigens and distinguish among serovars (e.g., Escherichia coli O157:H7)
Axial Filaments are also called
endoflagella
axil filaments are found in
spirochetes
axial filaments are anchored at
one end of the cell
axil filament rotation causes cells to
move like a corkscrew
Hairlike appendages that allow for attachment
fimbriae
Pili are
Involved in motility (gliding and twitching motility)
Conjugation pili involved in
DNA transfer from one cell to another
Prevents osmotic lysis and protects the cell membrane
cell wall
cell walls are made of
peptidoglycan (in bacteria)
cell wall contributes to
pathogenicity
Polymer of a repeating disaccharide in rows:
N-acetylglucosamine (NAG)
N-acetylmuramic acid (NAM)
Peptidoglycan
Peptidoglycan
rows are linked by
polypeptides
N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) joined as in a
peptidoglycan.
Thick peptidoglycan/
Teichoic acids are?
Gram-Positive Cell Walls
Have a Thin peptidoglycan on the
Outer membrane
and found in the Periplasmic space
Gram-Negative Cell Walls
Gram-Positive Cell Walls are what kind of acid
Teichoic acids
- Lipoteichoic acid links cell wall to plasma membrane
- Wall teichoic acid links the peptidoglycan
- Carry a negative charge
- Regulate movement of cations
Gram-Positive Cell Walls in Polysaccharides and teichoic acids provide
antigenic specificity
Gram-Negative Cell Walls have what between the outer membrane and plasma membrane
Periplasm between the outer membrane and the plasma membrane contains peptidoglycan
Outer membrane of Gram-Negative Cell Walls are made of
polysaccharides, lipoproteins, and phospholipids
Gram-Negative Cell Walls protect from
phagocytes, complement, and antibiotics
Gram-Negative Cell Walls are made of
Made of lipopolysaccharide (LPS)
- O polysaccharide functions as antigen (e.g., E.coli O157:H7)
- Lipid A is an endotoxin embedded in the top layer
what form channels through membranes in Gram-Negative Cell Walls
Porins
Cell Walls and the Gram Stain Mechanism
Crystal violet-iodine crystals form inside cell
Crystal violet-iodine crystals form inside cell
gram positive
- Alcohol dehydrates peptidoglycan
- CV-I crystals do not leave
Crystal violet-iodine crystals form inside cell
gram negative
- Alcohol dissolves outer membrane and leaves holes in peptidoglycan
- CV-I washes out; cells are colorless
- Safranin added to stain cells
Gram-Positive Cell Walls have what in the basal body of the flagella
2 rings
Gram-Positive Cell Walls produce
exotoxins
Gram-Positive Cell Walls have high susceptibility to
penicillin
Gram-Positive Cell Walls are disrupted by
lysozyme
Gram-Negative Cell Walls have what in the basal body of flagella
4-rings
Gram-Negative Cell Walls produce
endotoxins and exotoxins
Gram-Negative Cell Walls have susceptibility to penicillin
low
Atypical Cell Walls have
Acid-fast cell walls
- Like gram-positive cell walls
- Waxy lipid (mycolic acid) bound to peptidoglycan
- Mycobacterium
- Nocardia
- Stain with carbolfuchsin
Atypical Cell Walls consist of
1) Mycoplasmas
- Lack cell walls
- Sterols in plasma membrane
2) Archaea
- Wall-less, or
- Walls of pseudomurein (lack NAM and D-amino acids)
Damage to the Cell Wall can happen by
1) Lysozyme hydrolyzes bonds in peptidoglycan
2) Penicillin inhibits peptide bridges in peptidoglycan
3) Protoplast is a wall-less gram-positive cell
4) Spheroplast is a wall-less gram-negative cell
- -Protoplasts and spheroplasts are susceptible to osmotic lysis
5) L forms are wall-less cells that swell into irregular shapes
is a wall-less gram-positive cell that damages the cell wall
protoplast
is a wall-less gram-negative cell that damages the cell wall
spheroplast
Protoplasts and spheroplasts are susceptible to
osmotic lysis
are wall-less cells that swell into irregular shapes
L forms
Penicillin does what in peptidoglycan
inhibit peptide bridges damaging the cell wall
Lysozymes do what in peptidoglycan that damages the cell wall
hydrolyzes bonds
The Plasma (Cytoplasmic) Membrane
1) Phospholipid bilayer that encloses the cytoplasm
2) Peripheral proteins on the membrane surface
3) Integral and transmembrane proteins penetrate the membrane
Fluid mosaic model
1) Membrane is as viscous as olive oil
2) Proteins move freely for various functions
3) Phospholipids rotate and move laterally
4) Self-sealing
selective permeability does what in the plasmas membrane
allows the passage of some molecules, but not others
cell membrane contain
enzymes for ATP production
Some membranes have photosynthetic pigments on foldings called
chromatophores
Damage to the membrane by alcohols, quaternary ammonium (detergents), and polymyxin antibiotics causes
leakage of cell contents
Passive processes of materials across the membranes
substances move from high concentration to low concentration; no energy expended
active processes of movement of materials across membranes
substances move from low concentration to high concentration; energy expended
Simple diffusion
movement of a solute from an area of high concentration to an area of low concentration
Simple diffusion is what kind of process
passive
simple diffusion continues until
molecules reach equlibrium
Facilitated diffusion
solute combines with a transporter protein in the membrane
facilitated diffusion, active or passive diffusion
passive diffusion
Facilitated Diffusion transports
ions and larger molecules across a membrane with the concentration gradient
Osmosis
the movement of water across a selectively permeable membrane from an area of high water to an area of lower water concentration
osmosis goes through what layer
lipid layer
aquaporins are involved
in osmosis and are water channels
osmosis, active or passive transport
passive
Osmotic pressure
the pressure needed to stop the movement of water across the membrane
Isotonic solution
solute concentrations equal inside and outside of cell; water is at equilibrium
Hypotonic solution
solute concentration is lower outside than inside the cell; water moves into cell
Hypertonic solution
solute concentration is higher outside of cell than inside; water moves out of cell
Active transport
: requires a transporter protein and ATP; goes against gradient
Group translocation:
requires a transporter protein and phosphoenolpyruvic acid (PEP); substance is altered as it crosses the membrane
Group translocation.. active or passive transport
active
The substance inside the plasma membrane
cytoplasm
cytoplasm is made up of
Eighty percent water plus proteins, carbohydrates, lipids, and ions
Cytoskeleton
The Nucleoid is made up of
Bacterial chromosomes
Plasmids
Bacterial chromosome
circular thread of DNA that contains the cell’s genetic information
Plasmids
extrachromosomal genetic elements; carry non-crucial genes (e.g., antibiotic resistance, production of toxins)
Sites of protein synthesis
ribosomes
ribosomes are made up of
protein and ribosomal RNA
Inclusions
1) Metachromatic granules (volutin)—phosphate reserves
2) Polysaccharide granules—energy reserves
3) Lipid inclusions—energy reserves
4) Sulfur granules—energy reserves
5) Carboxysomes—RuBisCO enzyme for CO2 fixation during photosynthesis
6) Gas vacuoles—protein-covered cylinders that maintain buoyancy
7) Magnetosomes—iron oxide inclusions; destroy H2O2
Endospores
Resting cells; produced when nutrients are depleted
Endospores are resistant to
to desiccation, heat, chemicals, and radiation
endospores are produced by
Produced by Bacillus and Clostridium
Sporulation
: endospore formation
Germination
: endospore returns to vegetative state
Flagella and Cilia
Projections used for locomotion or moving substances along the cell surface
Flagella
long projections; few in number
Cilia
short projections; numerous
Flagella and cillia both have
microtubules made of the protein tubulin
Microtubules are organized as
nine pairs in a ring, plus two microtubules in the center (9 + 2 array)
Allow flagella to move in a wavelike manner
microtubules
cell walls are found
in plants algae and fungi
cell walls are made of
carbohydrates
Glycocalyx
are found
in animal cells
what are Glycocalyx
Carbohydrates bonded to proteins and lipids in the plasma membrane
Compare The Plasma (Cytoplasmic) Membrane to the prokaryotic cell membranes
Similarities to prokaryotic cell membrane structure
- Phospholipid bilayer
- Integral and peripheral proteins
Differences to prokaryotic cell membrane structure
- Sterols—complex lipids
- Carbohydrates—for attachment and cell-to-cell recognition
Plasma (Cytoplasmic) Membrane similarities and differences to prokaryotic cell membrane functions
Similar in function to prokaryotic cell membranes
- -Selective permeability
- -Simple diffusion, facilitated diffusion, osmosis, active transport
Differences in function
- -Endocytosis—phagocytosis and pinocytosis
- -Phagocytosis: pseudopods extend and engulf particles
- -Pinocytosis: membrane folds inward, bringing in fluid and dissolved substances
Cytoplasm
substance inside the plasma and outside the nucleus
Cytosol
fluid portion of cytoplasm
Cytoskeleton
made of microfilaments and intermediate filaments; gives shape and support
Cytoplasmic streaming
movement of the cytoplasm throughout a cell
ribosomes are the site of
protein synthesis
DNA is complexed with
histone proteins to form chromatin
During mitosis and meiosis, chromatin condenses into
chromosomes
Nucleus is the
Double membrane structure (nuclear envelope) that contains the cell’s DNA
Endoplasmic reticulum is the
Folded transport network
Rough ER:
studded with ribosomes; sites of protein synthesis
Smooth ER
no ribosomes; synthesizes cell membranes, fats, and hormones
Golgi Complex
1) Transport organelle
2) Modifies proteins from the ER
3) Transports modified proteins via secretory vesicles to the plasma membrane
Mitochondria
1) Double membrane
2) Contain inner folds (cristae) and fluid (matrix)
3) Involved in cellular respiration (ATP production)
Lysosomes
are organelles that
- Vesicles formed in the Golgi complex
- Contain digestive enzymes
Vacuoles
are organelles that
- Cavities in the cell formed from the Golgi complex
- Bring food into cells; provide shape and storage
Chloroplasts are the locations for
photosynthesis
Chloroplast contain
flattened membranes (thylakoids) that contain chlorophyll
Peroxisomes
are organelles that
oxidize fatty acids
Centrosomes are organelles made up of
Networks of protein fibers and centrioles
Form the mitotic spindle; critical role in cell division
Life arose as simple organisms (eukaryotes)
3.5 to 4 billion years ago
First eukaryotes evolved
2.5 billion years ago
Endosymbiotic theory
- Larger bacterial cells engulfed smaller bacterial cells, developing the first eukaryotes
- Ingested photosynthetic bacteria became chloroplasts
- Ingested aerobic bacteria became mitochondria
