MODULE 4 Flashcards
The bacterial cell wall is composed of a macromolecular network called
peptidoglycan
Peptidoglycan consists of a repeating _____ attached by ______ to form a lattice that surrounds and protects the entire cell
dissacharide
polypeptide
The disaccharide portion is made up of monosaccharides called
N-acetylglucosamine (NAG)
N-acetylmuramic acid (NAM)
In gram positive cell wall bacteria, the cell wall consists of ___ layers of ______
many layers of peptidoglycan
Gram positive cell wall contain
1.
2.
3.
- teichoic acid
- lipoteichoic acid
- wall teichoic acid
Gram negative cell wall contain only
a thin layer of peptidoglycan
a gel-like fluid between the outer membrane and the plasma membrane.
periplasm
Gram negative cell wall composed of
lipopolysaccharide (LPS)
lipoproteins
phospholipids
is a large complex molecule that contains lipids and carbohydrates
lipopolysaccharide
lipopolysaccharide consists of three components
lipid A
core polysaccharide
O polysaccharide
is the lipid portion of the LPS and is embedded in the top layer of the outer membrane.
Lipid A
lipid A functions as a
endotoxin
is responsible for the symptoms associated with infections by gram-negative bacteria such as fever, dilation of blood vessels, shock, and blood clotting.
lipid A
is attached to lipid A and contains unusual sugars
core polysaccharide
extends outward from the core polysaccharide and is composed of sugar molecules.
O polysaccharide
The O polysaccharide functions as
-antigen
-useful for distinguishing species of gram negative bacteria
stains both gram- positive and gram-negative cells purple because the dye enters the cytoplasm of both types of cells.
crystal violet
forms large crystals with the dye that are too large to escape through the cell wall.
iodine (the mordant)
provides a contrasting color to the primary stain (crystal violet).
safranin
What are the structures internal to the cell wall
plasma membrane
cytoplasm
nucleoid
ribosomes
inclusions
is a thin structure lying inside the cell wall and enclosing the cy- toplasm of the cell
plasma membrane
plasma membranes have
selective permeability
This term indicates that certain molecules and ions pass through the membrane, but that others are prevented from passing through it
selective permeability
What are the permeability factors
size
charge
polarity
are also important to the breakdown of nutrients and the production of energy.
plasma membrane
pigments and enzymes involved in photosynthesis are found in infoldings of the plasma membrane that extend into the cytoplasm.
These membranous structures are called
chromatophores
thylakoids
Materials move across plasma membranes of both prokaryotic and eukaryotic cells by two kinds of processes
passive and active
substances cross the membrane from an area of high concentration to an area of low concentration
passive processes
the cell must use energy (ATP) to move substances from areas of low concentration to areas of high concentration
active processes
Passive processes include
simple diffusion
facilitated diffusion
osmosis
is the net movement of molecules or ions from an area of high concentration to an area of low concentration
simple diffusion
integral membrane proteins function as channels or carriers that facilitate the movement of ions or large molecules across the plasma membrane
facilitated diffusion
integral proteins are called
transporters or permeases
is the net movement of solvent molecules across a selectively permeable membrane from an area with a high concentration of solvent molecules (low concentration of solute molecules) to an area of low concentration of solvent molecules (high concentra9on of solute molecules)
osmosis
What are the three tonicity of the osmosis?
isotonic solution
hypotonic solution
hypertonic solution
No net movement of water occurs.
isotonic solution
Water moves into the cell. If the cell wall is strong,
it contains the swelling. If the cell wall is weak or damaged, the cell bursts (osmotic lysis).
hypotonic
Water moves out of the cell, causing its cytoplasm to shrink (plasmolysis).
hypertonic solution
Among the substances actively transported are
ions
amino acids
simple sugars
for a prokaryotic cell the term refers to the substance of the cell inside the plasma membrane
cytoplasm
cytoplasm is about
80% water
proteins
carbohydrates
lipids
inorganic ions