Chapter 3: Prokaryotic Profile Flashcards
How to distinguish prokaryotes from eukaryotes
the way their DNA is packaged (lack of nucleus)-circular DNA, the plasmid and the thread-like chromosome; the makeup of their cell wall (peptidoglycan and other unique chemicals); their internal structure (lack of membrane-bounded organelles)
All bacterial cells possess…
a cell membrane cytoplasm ribosomes a cytoskeleton one (or a few) chromosome(s)
Some bacterial cells possess…
flagella, pili, and fimbriae an outer membrane plasmids inclusions endospores intracellular membranes
Average size of prokaryotic cells
1 um
Pleomorphism
Cells of one species may vary in shape and size; caused by variations in cell wall structure
Cocci
spheres
Diplococci
two spheres
Streptococci
chain of spheres
Tetrad
4 coccis in a square
Sarcina
cubic configuration of 8 cocci
Staphylococci
grape-like clusters of cocci
Name this bacterial shape
Coccus
Name this bacterial shape
Coccobacillus
Name this bacterial shape
Vibrio (gently curved)
Name this bacterial shape
Bacillus
Name this bacterial shape
Spirillum
Name this bacterial shape
Spirochete
Three parts of a flagella
Filament; Hook; Basal Body
Flagellin
the protein that composes the filament of the flagella
Pilli
Projection that helps bacteria to fasten onto surfaces such as host membranes.
Monotrichous
Single flagella
Lophotrichous
small bunches or tufts of flagella
Amphitrichous
Flagella at both poles of the cell
Peritrichous
flagella dispersed randomly over the cell
Chemotaxis
Chemical signals that trigger bacterial movement
Runs (movement)
smooth linear movement towards a stimulus
Tumbles (movement)
flagellar rotation reverses, causing cell to stop and change its course
Fimbriae
short, thin, hairlike, proteinaceous appendages up to 1,000/cell; mediate attachment to surfaces
Capsule
Outer layer of cell usually composed of polysaccharides; well organized and not easily removed from cell
Slime Layer
similar to capsules except diffuse, unorganized and easily removed
Glycocalyx
a capsule or slime layer composed of polysaccharides; used to avoid phagocytosis and for adhesion
Clincial Significance of Glycocalyx
Adherence is a major part of infection (staying in), especially in respiratory and urinary tract infections.
Function of Glycocalyxes
protection from host defenses (e.g., phagocytosis); protection from harsh environmental conditions (e.g., desiccation) , chemicals or osmotic stress; attachment to surfaces; facilitate motility; nutrient storage
Composition of Cell Envelope
cell wall; cell membrane; outer membrane in some bacteria
The bacterial cell wall is a protective barrier against…
Osmotic pressure changes and other environmental stressors
Gram-Positive Bacteria Stain Color
Blue/purple
Gram-Negative Bacteria Stain Color
Pink/red
Peptidoglycan
The primary structure of the cell wall; repeating sugars of N-acetyl glucosamine (NAG) N-acetyl muramic acid (NAM)
Teichoic Acid
polymers of glycerol or ribitol joined by phosphate groups; in the cell wall
Wall teichoic acids
go part way through the wall; protrudes above the wall; gram-positive
Lipoteichoic acids
go completely through the wall and link to the plasma membrane; protrudes above the wall; gram-positive
M Protein
a virulence factor; it protrudes from the cell wall; it is required for infection; it is highly susceptible to mutations; gram-positive
Mycolic Acid
found in myobacterium; waxy liquid incorporated into cell wall; makes cell extremely resistant to environmental stress; acts as a barrier against antibiotics & host defenses; gram-positive
Periplasmic Space
between plasma and cell wall; smaller in gram-positive
Exoenzymes
Enzymes secreted by gram-positive bacteria that inflict damage on host’s tissues
Unique Features of Gram-Positive Wall
Thick peptidoglycan; Phospholipid molecules; one membrane; Teichoic acid & lipoteichoic acid
lipopolysaccharides
compose the outer membrane of Gram-Negative wall; act as a barrier
Phospholipid Molecules
compose the outer wall of the Gram-Positive bacterium
Teichoic Acids - present or not present in Gram-negative and Gram-positive?
Gram-negative: absent
Gram-positive: present
Lipid A
A lipopolysaccharide endotoxin that stimulates fever
Unique features of Gram-Negative Wall
Thin peptidoglycan; Lipopolysaccharide; Two membranes; Porins
Cytoplasmic Membrane
lipid bilayer with proteins embedded; contains enzymes of respiration and ATP synthesis since prokaryotes lack mitochondria
Name differences between Gram-Positive and Gram-Negative: Peptidoglycan, Teichoic Acid, Lipids, Outer membrane, Toxins, Sensativity to Antibiotics

Six major strucutres found in cell wall
Plasma membrane; Nuclear region; Plasmids; Ribosomes; Inclusion bodies; Endospores
Cytoplasm
site of nearly all chemical reactions; contains DNA in nucleoid; 70-80% water; soluble proteins, salts, and carbs
Plasma Membranes
Encompasses the cytoplasm
Functions of the Plasma Membrane (4)
separation of cell from its environment; selectively permeable barrier; transport systems aid in movement of molecules; detection of and response to chemicals in surroundings with the aid of special receptor molecules in the membrane
Phospholipid Layer
Composed of polar heads (phillic) and non-polar heads (phobic)
Peripheral Protein
a membrane protein that is loosely associated and easily removed
Integral Protein
Membrane protein that is embedded and not easily removed
ATP Production occurs…
at the plasma membrane; proteins associated with electron transport are here
Name the three types of membrane transport
Osmosis; Passive Transport; Active Transport
Osmosis
water chases the concentration of solutes (higher to lower concentration)
Simple Diffusion
Type of passive transport; does not require ATP (higher to lower concentration)
Facilitated Diffusion
does not require ATP but uses carrier proteins called permease proteins
Active Transport
requires ATP (against a concentration gradient)
Plasmid
single, circular bacterial DNA
Nucleoid
Dense area of the prokaryotic cell that contains the DNA
S Unit
The unit used to measure ribosomes by their density
Small Subunit S Value
30S
Large Subunit S Value
50S
Overall S value of prokaryotic ribsosome
70S
Ribosome is _____% rRNA and ______% protein
60% and 40%
S value of Eukaryotic Ribsome
80S
Function of Ribosome
Translates mRNA into proteins
Inclusion Bodies/Granules
manufactured in response to environment; stores extra nutrients
Cytoskeleton
shape of cell mostly determined by peptidoglycan; actin and tubulin are proteins that may also alter cytoskeleton
Bacterial Endospores
small, dormant, resistant derivitave of a bacterial cell; heat resistance; spore coats protect against radiation and chemicals