(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