(exam 1) ch 4 prokaryotes and eukaryotes Flashcards
what are 2 important differences between prokaryotic cells and eukaryotic cells?
1) structure of the cell walls and structure of ribosomes differ 2) prokaryotes lack organelles and a true nucleus
what is morphology?
form and structure of living things
what is bacterial morphology?
size, shape, and arrangement of bacterial cells
what are the primary shapes of bacteria?
1) coccus (spherical) 2) bacillus (rod shaped) 3) spiral
what are the different arrangements basic names?
pairs, chains, groups of four, cubelike groups of eight, and clusters
what is coccus?
spherical shaped bacteria cocci (plural)
what is the arragement name for cocci in pairs?
diplococci
what is the arrangement name for cocci in chains?
streptocci
what is the arrangement name for cocci in clusters?
staphylococci
what is bacillus?
rod-shaped bacteria; bacilli (plural)
what is the arrangement name for bacilli in pairs?
diplobacilli
what is the arrangement name for bascilli in chains?
streptobacilli
what is spiral bacteria?
bacteria with one or more twists
what is vibrio bacteria?
spiral bacteria with curved rods ; vibrios (plural)
what is spirillum bacteria?
spiral bacteria that is helical and rigid; spirillum (plural)
what is spirochete bacteria?
spiral bacteria that is heclical and flexible; spirochetes (plural)
what is glycocalyx on the outside of the cell wall?
it is a visous and gelatinous polymer made of polysaccharide and/or polypeptide chain (depending on the species)
what are the two types of glycocalyx outside the cell wall and what are their characteristics?
1) capsule: neatly organized and firmly attached (determined by negative staining)
2) slime layer: unorganized and loose, often forms net-like structures between cells (useful for biofilms)
what is the importance of the glycocalyx outside layer?
contributes to the virulence (ability of pathogence to cause disease)/ capsules prevent phagocytosis; protects against dehydration; important for biofilms (in terms of formation, communication, and attachment)
what is flagella? (singular flagellum)
long filamentus appendage that provide bacteria with motility which is advantageous (allowing bacteria to move towards favorable conditions and move away from adverse condition)
what is a fimbriae?
hairlike appendage that allows for attchment and contributes to biofilm formation and virulence
what is pili?
involved in motility; conjugation pili ‘sex pili’ involved in DNA transfer from one cell to another
what is the bacterial cell wall?
complex, semi-rigid structure; protects cell and provides shape
what are three main functions of the bacterial cell wall?
1) provides and maintains cell shape 2) surrounds and protects the cell membrane (prevents osmotic lysis which is bursting caused by water) 3) anchorage point for flagella
what is the clinical importance of the cell wall?
contributes of pathogenicity / many antibiotics affect disrupt the cell wall and differences in composition are critical for identification (like for gram stain!)
what is the composition of the cell wall in prokaryotes?
a network of molecules called peptidoglycan (made of proteins and carbohydrates)
what are the major differences between the gram positive and gram negative bacteria in terms of their cell walls?
gram positive = thick peptidoglycan layer
gram negative = thin peptidoglycan layer and outer membrain composed of lipopolysaccharide
why are some bacteria acid-fast bacteria?
because some bacteria have a waxy layer that forms outside peptidoglycan which prevents normal staining
why do we target the cell wall?
because cell wall damamge exposes bacteria to osmotic lysis which is bursting caused by water
how do lysozomes target the cell wall?
eukaryotic enzyme found in sweat, tears, mucus, and saliva cuts bonds in peptidoglycan
how do antibiotics (beta-lactam) target the cell wall?
penicillin inhibits peptidoglycan synthesis
what is the plasma membrane structure?
phospholipid bilayer that encloses the cytoplasm; it is as viscous as olive oil (not rigid); it contains peripheral and integral proteins in the membrane
what is the function of the plasma membrane?
acts as a selective barrier that allows the passage of some molecules but not others (selective permeability); also performs nutrient breakdown and energy production
what are two types of movement of materials across membranes?
1) Passive processes
2) Active processes
what are passive processes?
substances move from high concentration to low concentration; no energy is expended
what are active processes?
substances move from low concentration to high concentration; energy is expended
what is simple diffusion?
(passive process) molecules move from an area of high concentration to an area of low concentration which continues until the molecules reach equilibrium; no energy is expended
what is facilitated diffusion?
(passive processes) transport proteins move molecules from an area of high concentration to areas of low concentration (used for larger molecules or hydrophobilic ions) no energy expended
what is osmosis?
(passive process) movement of water across membrane from an area of high water concentration to an area of lower water concentration (through lipid layer or aquaporins) no energy expended
what is an isotonic solution?
(form of osmosis / passive process) solute concentrations are equal inside and outside of the cell; water is at equilibrium (no energy expended)
what is a hypertonic solution?
(osmosis / passive process) solute concentration is higher outside the cell than inside; water moves out of the cell (no energy expended)
what is a hypotonic solution?
(osmosis / passive process) solute concentration is lower outside than inside the cell; water moves into cell (no energy expended)
why is the cell wall so important for bacterial cells?
because it prevents osmotic lysis (when the plasma membrane reptures due to excess water moving into cell)
what does active transport require?
requires a transporter protein and the substance is not changed during transport (energy is expended)
what is group translocation?
exclusive to prokaryotes only (form of active transport / requires energy) requires a transporter protein, substance is altered as it crossess the membrane so that is it cannot exit ever again
what is nucleoid (in prokaryotes)?
bacterial chromosome; circular thread of DNA that contains the cell’s genetic material
what are plasmids (in prokaryotes)?
extrachromosomal genetic elements that carry non-crucial genes (antibiotic resistance, production of toxins) requires extra energy so not all bacteria cells have them
what are ribosomes (in prokaryotes)?
sites of protein synthesis; made of protein and ribosomal RNA; they different sub units are different between euk and pro because many antibiotics inhibit protein synthesis at prokaryotic ribosomes (so it only hurts bacterial cells not us)
what are inclusions (prokaryotes) ?
act as reserve deposits for cetain nutrients (stored nutrients can be used when they become low in environment)
what are endospores (prokaryotes)?
resting (dormant) cells; produced when nutrients are scarce or depleted; resistant to desiccation, heat, chemicals, and radiation
what is sporulation (in prokaryotes?)
endospore formation
what are cilia (eukaryotes) ?
short projections; numerous; used for locomotion or moving substances along the cell surface
what is cell wall (eukaryotes)?
found in plants, algae, and fungi; made of carbohydrates; far less complex than in prokaryotes
what is glycocalyx (eukaryotics)?
found in animal cells; carbohydrates bonded to the plasma membrane
similarites in structure of plasma membrane between eukaryotes and prokaryotes?
phospholipid bilayer and integral and peripheral proteins
differences in structure of the plasma membrane between eukaryotes and prokaryotes?
(IN eukaryotes) sterols- complex lipids (provides protection from osmotic lysis); carbohydrates- for attachment and cell-to-cell recognition
similarities in function of plasma membrane between eukaryotes and prokaryotes?
eukaryotes have selective permeability; simple diffusion, faciliated diffusion, osmosis, and active transport
differences in function of plasmamembrane between eukaryotes and prokaryotes?
eukaryotes have endocytosis: segment of plasma membrane surrounds a particale, encloses it and brings it into the cell
what are three types of endocytosis?
1) phagocytosis 2) pinocytosis 3) receptor-mediated endocytosis
what is phagocytosis?
pseudopods extend and engulf particles (white blood cells use this for immunity)
what is pinocytosis?
when membrane folds inward, bringing in fluid and dissolved substances (basic process)
what is receptor-mediated endocytosis?
incoming substances bind to receptors outside of the cell to trigger endocytosis (triggered to happen)
what is the cytoskeleton in eukaryotes made of?
made of microfilaments and intermediate filaments; provides shape and support
what are ribosomes (eukaryotic cells)?
sites of protein synthesis; slightly larger than prokaryotic ribosomes (different in structure)
what are organelles (eukaryotic cells)?
have specific shapes and specialized functions ; characteristic of eukaryotes
what is the nucleus (in eukaryotic cells)?
double membrane structure (nuclear envelope) that contains the cell’s DNA
what is the endoplasmic reticulum (eukaryotic cells)?
folded transport network consisting of rought ER and smooth ER
what is rough ER (eukaryotic cells)?
part of endoplasmic reticulum; studded with ribosomes; sites of protein synthesis
what is smooth ER (eukaryotic cells)?
part of endoplasmic reticulum; no ribosomes; synthesizes cell membranes, fats, and hormones
what is the golgi complex (eukaryotic cells)?
transport organelle, modifies proteins from the ER
what are lysosomes (eukaryotic cells)?
vesicles formed in the golgi complex; contain digestive enzymes; major component of white blood cells
what are vacuoles (eukaryotic cells)?
cavities in the cell formed from the golgi complex; bring food into cells; provide shape and storage
what is the mitochondria (eukaryotic cells)?
‘power house of the cell’ involved in cellular respiration (ATP production)
what are cholorplasts (eukaryotic cells)?
location of photosynthesis but found only in algae and green plants
what are peroxisomes (eukaryotic cells)?
oxidize fatty acids; destroy
what are centrosomes?
form the mitotoc spindle; critical role in cell division
