module 1-1 part B Flashcards
the plasma membrane contains lipid and proteins:
lipids form bilayer
proteins are imbedded or associate with lipids
lipid
polar ends:
nonpolar ends:
polar: hydrophilic, interact with water
nonpolar: hydrophobic, insoluble to water (fatty acid tails)
loosely associated with the membrane and easily removed
peripheral proteins
embedded within the membrane and not easily removed
integral proteins
separation of cell from its environment
selectively permeable barrier
functions of the plasma membrane
granules of organic or inorganic material that are stockpiled by the cell for future use
-some are inclosed by single-layered membrane
inclusion bodies
complex structures consisting of protein and RNA
ribosomes
site of protein synthesis!
ribosomes
prokaryotic: 70S
eukaryotic: 60S
irrregular shaped
location of chromosome
not membrane bound
nucleoid
describe the prokaryotic chromosome:
closed circle, double stranded DNA molecule
looped and coiled
describe unusual nucleoids:
-some prokaryotes have <1 chromosome
-some have chromosomes that are linear doubled-stranded DNA instead of circular
these are small, closed circular DNA molecules that exist and replicate independently of chromsomes
-not required for growth and reproduction
-carry genes for selective advantage (drug resistance)
plasmids
provides shape to cell, protects from osmotic lysis, toxic substances
cell wall
cell walls of bacteria are divided into two major groups dependings on gram-stain
gram positive: purple and think peptidoglycan
gram negative: pink and 2 portions to cell wall (outer membrane and thin peptidoglycan) also has periplasmic space
gap between plasma membrane and cell wall. this is found in:
gap between plasma membrane (aka peptidoglycan) and outer membrane. this is found in:
- gram +
- gram -
substances that occupy periplasmic space
periplasm
found in periplasm of gram - bacteria
functions include:
1. nutrient acquisition
2. electron transport
3. peptidoglycan synthesis
4. modification of toxic compounds
periplasmic enzymes
these are secreted by gram positive bacteria
perform the same functions of periplasmic enzymes
exoenzymes
important component of both gram - and + bacteria:
polysaccharides formed from these subunits.
what are the two alternating sugars that form the backbone:
peptidoglycan structure
2 sugars:
NAG (N-acetylglucosamine)
NAM (N-acetylmuramic acid)
gram positive structure has what that connects the amino acids in the peptide portion
peptide interbridge
gram positive cell walls are composed primarily of peptidoglycan. they also contain large amounts of _______. this forms an anchor
teichoic acids
polymers of glycerol or ribitol joined by phosphate groups
teichoic acids
gram negative cell walls consist of a (thin/thick) peptidoglycan surrounded by an ______ _______
thin
outer membrane
the outer membrane in gram negative is composed of:
they do not have:
lipids, lipoorteins, and LPS (lipoolysaccharides)
no teichoic acids
these connect outer membrane to the peptidoglycan in gram negative bacteria
braun’s lipoproteins
sites of direct contact (possibly true membrane fusions) between plasma membrane and outer membrane) in gram negative bacteria
substances may move directly into cell thru adhesion sites
adhesion sites
LPS (lipopolysaccharides) consist of 3 parts:
lipid A
core polysaccharide
O side chain (o antigen)
importance of LPS
- protection from host defense=
- contributes to negative charge on cell surface=
- helps stabilize outer membrane structure:
- can act as an endotoxin=
- O antigen
- core polysaccharide
- lipid A
- lipid A
this is more permable that the plasma membrane due to the presence of porin proteins and transporter proteins
outer membrane in gram negative bacteria
