Ch 4- prokaryotes 2 Flashcards
difference between prokaryotic and eukaryotic PM
both contain phospholipids
euk- contains carbohydrates and sterols (cholesterol), more rigid
PM structure
phosopholipids, hydrophilic polar head points outwards, fatty acid points inward (bilayer)
2 kinds of proteins in a PM and what they do
integral- for cell transport
peripheral - at inner and outer surfaces of PM. function as enzymes that catalyze reactions, provide support
net overall movement of molecules or ions from high conc to low (passive=no energy required)
simple diffusion
integral proteins that function as nonspecific or specific transporters to facilitate the movement of ions or large molecules across PM (passive=no energy)
facilitated diffusion
net movement of solvent molecules (like H2O) across a semipermeable membrane from high to low conc
osmosis
integral proteins that function as water channels
aquaporins
the nucleoid of the prokaryote is analagous to the what of the eukaryote
nucleus
the prokaryote nucleoid differs from the nuclues how
no nuclear envelope (membrane)
possible nucleoid shapes
spherical, elongated, dumbbell
in addition to bacterial chromosome (in the bacterial nucleoid), they often contain small circular double-stranded DNA molecules called
plasmids
why plasmids are beneficial
allow transfer of genes; may carry beneficial genes
site of protein synthesis in both prokaryotes and eukaryotes
ribosomes
where ribosomes are located
cytoplasm
structure of a ribosome
2 subunits (each consisting of protein and RNA), a small and large subunit
difference between eukaryote and prokaryote ribosome
prokaryotic smaller (70s) euk 80s
what are Svedberg units
measure how quickly ribosome will descend in a liquid (rate of sedemntation)
what are inclusions
different kinds of reserve deposits in cytoplasm(accumulate nutrients when plentiful, use when deficient)
metachromatic granules (volutin)
phosphate reserve
polysaccharide granules
energy reserves of glycogen and starch (can be seen when dyed w iodine, dyes glycogen)
lipid inclusions
energy reserves of lipids
sulfur granules
reserves of sulfur (some bacteria derrive energy by oxidizing sulfur, use to make ATP)
diseases caused by acid fast bacteria
leprosy, tuberculosis
carboxysomes
inclusions that contain enzyme ribulose 1,5-diphosphate; photosynthetic bacteria use for carbon fixation
gas vacules
inclusion found in many aquatic prokaryotes, protein covered air bubble used for buoyancy
magnetosomes
inclusion containing iron oxide, act as magnets, protect from H2O2 (hydrogen peroxide)
why do endospores form
survival function, response to adverse environmental conditions like ig essential nutrients are depleted
what geni form endospores
Clostridium, bacillus
what are endospores
highly durable dehydrated cells w thick walls and additional layers. when released in environment can survive extreme heat, lack of water, toxic chemicals, radiation
how endospores are formed
1) a replicated bacterial chromosome and portion of cytoplasm are isolated by an ingrowth of the plasma membrane (spore septum)
2) the PM starts to surround them
3) spore septum surrounds isolated portion, forming forespore (2 membranes now surround)
4) peptideglycan forms between 2 membranes ‘
5) spore coat forms
6) endospore released
when an endospore returns to vegetative state(triggered by physical or chem damage to coat)
germination
what component of an endospore protects the DNA from damage
DPA (diplicolinic acid)
importance of endospores in food industry and clinical importance
they are resistant to processes that normally kill vegetative cells (heating, freezing, etc.)
eukaryotes: flagella vs cilia
projections few and long. used by Euglena algae: flagella
short and numerous. used by protozoa : cilia
difference between eukaryotic cell wall and prokaryotic
eukaryotic dont contain peptidoglycan (cellulose, chitin, etc.) also much chemically simpler than prokaryotic
difference between eukaryotic and prokaryotic glycocalyx
prok- slime layer or capsule
difference between eukaryotic and prokaryotic plasma membrane
euk contain sterols and carbohydrates (serve as receptor sites and attachment sites), can use endocytosis (bring large molecules into cell)
3 types of endocytosis done by eukaryotes
phagocytosis, pinocytosis, receptor-mediated endocytosis
difference between prokaryotic and eukaryotic cytoplasm
euk- have a cytoskeleton (microtubules and microfilaments), cytoplasm moves through cell distributing nutrients (cytoplasmic streaming)
also- important enzymes found in organlles rather than in cytoplasm like in prokaryotes
difference between prok and euk ribosomes
larger in eukaryotes (60s+40s=80s)
difference between free-ribosomes and membrane-bound ribosomes
free-synthesize proteins used inside cell
membrane-bound(PM or endoplasmic reticulum)- synthesize proteins destined for insertion in PM or for export from cell
what is the nucleolus/ nucleoli (in eukaryotes)
condensed regoins of chromosomes where RNA is synthesized
diff between prok and euk division
euk undergo mitosis and meiosis (prok neither), DNA in form of chromatin coil into chromosomes during nuclear division
diff between prok and euk endoplasmic reticulum
prok doesnt have
diff between smooth and rough ER
rough-ribosomes, snythesize proteins
smooth- synthesize phospholipids,
difference between prokaryotic and eukaryotic DNA
prok-single circular chromosome (no histones-proteins found in euk nucleus)
euk- multiple linear chromosomes w histones
role of euk lysosomes
containt digestive enzymes to breakdown mlcls and digest bactera (Ex: WBCs contain lysosomes)
role of eukaryotic vacules
temporary storage, form during endocytosis to bring food into cell, take up water in plant cells to increase size and rigidity
role of mitochondria in eukaryotes
atp production ( inner membrane provides large surface area for chem reactions to occur)
role of peroxisomes in eukaryotes
uses enzymes to oxidize substances (sometimes toxic) like H2O2
role of eukaryotic centrosome
organizing center for mitotic spindle (pericentriolar material), critical role in cell division
