BIO 175 EXAM 2 Questions and Answers
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Slime layer A diffuse, unorganized layer pf polysaccharides and/or proteins that protect
the bacteria from losing water and composition.
Capsule Bound more tightly, more densely packed, and thicker than slime layers;
produces sticky (mucoid) character to colonies of agar; give bacterial cells a greater disease-
causing ability by protecting them against white blood cells.
Cell Envelope Chemically complex external covering that lie outside of the cytoplasm;
includes the cell wall, the cytoplasmic membrane, or an outer membrane.
Gram-Positive Bacterial Cell TWO LAYERS - Thicker peptidoglycan cell wall (20-80
nm) and a thin cytoplasmic membrane, as well as no outer membrane; stains purple under Gram
Stain. Has teichoid acids and lipoteichoic acids on surface.
Gram-Negative Bacterial Cells THREE LAYERS - Have outer membranes and a thin cell
wall (1-3 nm) and cytoplasmic membrane; have no acids sticking out of surface; stains red; more
susceptible to lysis with thin cell wall.
,Cell walls Helps hold shape of bacteria and hold everything together in different
pressures; built from peptoglycan; is strong but flexible, keeping cell from exploding when shape
or osmotic pressure changes.
Lysis The physical rupture or deterioration of a cell.
Nontypical Cell Wall Don't fit as either gram-positive or negative; difficult to stain.
Cell Membrane/Cytoplasmic Membrane Lowest, very thin (5-10nm) membranes
containing phospholipids (40%) and proteins (60%); provides a site for functions such as energy
reactions, nutrient processing, and synthesis; can regulate endo- and exocytosis.
L Forms Forms of bacteria that are wall-less in certain life stages.
Outer Membrane Contain specialized polysaccharides and proteins, with lipoproteins
connecting it to the cell wall; is a phospholipid bilayer with an upper layer that is dispersed with
lipopolysaccharides (act as signaling proteins and receptors); allows access in and out by channel
proteins called "Porin Proteins."
, Cytoplasm in Prokaryotes The gelatinous, aqueous interior of the cell that allows
everything to float about; 70% water and is a solvent for the sugars, amino acids, and salts
floating in it as nutrients.
Bacterial Chromosome Singular strand of DNA aggregated in a dense small area, called
the nucleoid. Can contain plasmids.
Plasmids Nonessential pieces of double-stranded DNAthat contain information not
necessary for living but instead hold evolutionary information; can be transferred from cell to
cell or handed off to offspring.
Ribosomes Made of ribosomal RNA and characterized by S units of 30s and 50s (total
70s); are sites for protein synthesis.
Inclusions Store nutrients for when food is low, store gas for floatation devices, or store
crystals of iron oxide for magnification to be used in movement (granules).
Verified by Experts
Slime layer A diffuse, unorganized layer pf polysaccharides and/or proteins that protect
the bacteria from losing water and composition.
Capsule Bound more tightly, more densely packed, and thicker than slime layers;
produces sticky (mucoid) character to colonies of agar; give bacterial cells a greater disease-
causing ability by protecting them against white blood cells.
Cell Envelope Chemically complex external covering that lie outside of the cytoplasm;
includes the cell wall, the cytoplasmic membrane, or an outer membrane.
Gram-Positive Bacterial Cell TWO LAYERS - Thicker peptidoglycan cell wall (20-80
nm) and a thin cytoplasmic membrane, as well as no outer membrane; stains purple under Gram
Stain. Has teichoid acids and lipoteichoic acids on surface.
Gram-Negative Bacterial Cells THREE LAYERS - Have outer membranes and a thin cell
wall (1-3 nm) and cytoplasmic membrane; have no acids sticking out of surface; stains red; more
susceptible to lysis with thin cell wall.
,Cell walls Helps hold shape of bacteria and hold everything together in different
pressures; built from peptoglycan; is strong but flexible, keeping cell from exploding when shape
or osmotic pressure changes.
Lysis The physical rupture or deterioration of a cell.
Nontypical Cell Wall Don't fit as either gram-positive or negative; difficult to stain.
Cell Membrane/Cytoplasmic Membrane Lowest, very thin (5-10nm) membranes
containing phospholipids (40%) and proteins (60%); provides a site for functions such as energy
reactions, nutrient processing, and synthesis; can regulate endo- and exocytosis.
L Forms Forms of bacteria that are wall-less in certain life stages.
Outer Membrane Contain specialized polysaccharides and proteins, with lipoproteins
connecting it to the cell wall; is a phospholipid bilayer with an upper layer that is dispersed with
lipopolysaccharides (act as signaling proteins and receptors); allows access in and out by channel
proteins called "Porin Proteins."
, Cytoplasm in Prokaryotes The gelatinous, aqueous interior of the cell that allows
everything to float about; 70% water and is a solvent for the sugars, amino acids, and salts
floating in it as nutrients.
Bacterial Chromosome Singular strand of DNA aggregated in a dense small area, called
the nucleoid. Can contain plasmids.
Plasmids Nonessential pieces of double-stranded DNAthat contain information not
necessary for living but instead hold evolutionary information; can be transferred from cell to
cell or handed off to offspring.
Ribosomes Made of ribosomal RNA and characterized by S units of 30s and 50s (total
70s); are sites for protein synthesis.
Inclusions Store nutrients for when food is low, store gas for floatation devices, or store
crystals of iron oxide for magnification to be used in movement (granules).
