[1S] UNIT 1.2 Bacterial Cell Structure Flashcards
PROKARYOTES VS EUKARYOTES: SIZE
0.4-2 um
Prokaryotes
PROKARYOTES VS EUKARYOTES: SIZE
10-100 um
Eukaryotes
PROKARYOTES VS EUKARYOTES: NUCLEAR BODY
Nucleoid in the cytosol
Prokaryotes
PROKARYOTES VS EUKARYOTES: NUCLEAR BODY
Enclosed in a membrane
Eukaryotes
PROKARYOTES VS EUKARYOTES: GENOME
Circular dsDNA (double stranded DNA); In the nucleoid, mesosome
Prokaryotes
PROKARYOTES VS EUKARYOTES: GENOME
Multiple, linear DNA; In the nucleus
Eukaryotes
PROKARYOTES VS EUKARYOTES: EXTRACHROMOSOMAL CDNA
Plasmids, Transposons, Episomes
*These are important in the antibiotic mechanism of the organism
Prokaryotes
PROKARYOTES VS EUKARYOTES: EXTRACHROMOSOMAL CDNA
Mitochondria, Chloroplast
Eukaryotes
PROKARYOTES VS EUKARYOTES: CELL DIVISION
Binary Fission
Prokaryotes
PROKARYOTES VS EUKARYOTES: CELL DIVISION
Mitosis
Eukaryotes
PROKARYOTES VS EUKARYOTES: CELL WALL
PRESENT (except in Mycoplasma and Ureaplasma)
Prokaryotes
PROKARYOTES VS EUKARYOTES: CELL WALL
ABSENT (except in Fungi)
Eukaryotes
PROKARYOTES VS EUKARYOTES: CYTOPLASMIC MEMBRANE
Present (phospholipids and protein)
No sterols present
Prokaryotes
PROKARYOTES VS EUKARYOTES: CYTOPLASMIC MEMBRANE
PRESENT (phospholipids and sterols)
Eukaryotes
PROKARYOTES VS EUKARYOTES: CELL ORGANELLES
- Present
- Absent
- Eukaryotes
- Prokaryotes
PROKARYOTES VS EUKARYOTES: SITE OF ENERGY PROD
Cytoplasmic Membrane or Plasma Membrane
Prokaryotes
PROKARYOTES VS EUKARYOTES: SITE OF ENERGY PROD
Mitochondria (powerhouse of the eukaryotic cell)
Eukaryotes
PROKARYOTES VS EUKARYOTES: SITE OF PROTEIN SYNTHESIS
Free Ribosomes
Ribosomes (70S)
Prokaryotes
PROKARYOTES VS EUKARYOTES: SITE OF PROTEIN SYNTHESIS
Rough ER
Ribosomes (80s)
Eukaryotes
PROKARYOTES VS EUKARYOTES: MOTILITY
Flagella
Prokaryotes
PROKARYOTES VS EUKARYOTES: MOTILITY
Flagella, Cilia, Pseudopod
Eukaryotes
Bacterial cell is made up of
70% Water & 30% Carbohydrates, Proteins, Lipids, Enzymes
Bacterial cell wall structures (2)
Cell envelope structures
Cytoplasmic structures
● Consists of Cell Wall and Cell Membrane
● Some bacteria may also possess capsules and slime layers
Cell Envelope Structures
● Outer membrane (gram-negative only)
● Cell wall (murein layer)
Cell Envelope Structures
CELL ENVELOPE: CELL WALL
Contains a thick layer of
peptidoglycan
Gram-positive
CELL ENVELOPE: CELL WALL
Contains thin layer of peptidoglycan
Gram-negative
CELL ENVELOPE: CELL WALL
Contains waxy substances (e.g. mycolic acids)
Acid fast
CELL ENVELOPE
○ Contains gel-like substances that capture nutrients
○ Contains enzymes needed for detoxification and degradation purposes
Periplasm
CELL ENVELOPE
T/F: Periplasm is distinct in gram-negative
T
CELL ENVELOPE
○ Is the deepest layer of the cell
○ Contains proteins and enzymes that are vital to cellular metabolism
○ Serves as osmotic barrier
Cell Membrane
● Gives shape to the bacterial cell
● Provides protection
Cell Wall
3 types of cell wall
Gram (+), Gram (-) and Acid Fast
Main constituent of cell wall
Peptidoglycan or Murein
Cell wall consists of these 2 alternating disaccharides and are linked by pentapeptides
■ NAG (N-Acetylglucosamine)
■ NAM (N-Acetylmuramic acid)
● Responsible for pathogenicity
● Serves as a point of anchorage of flagella
● Responsible for antigenic characteristic of certain bacteria
Cell Wall
CELL WALL PATHOGENICITY
prevents phagocytosis
M protein
CELL WALL PATHOGENICITY
prevent digestion
Mycolic Acid
● Serves as the target of antimicrobial agents
● Responsible for staining characteristic of the cell
Cell Wall
GRAM (+) VS GRAM (-) CELL WALL
Thick protective murein layer
Gram (+)
GRAM (+) VS GRAM (-) CELL WALL
Thinner Murein Layer (Inner Peptidoglycan Layer)
Gram (-)
GRAM (+) VS GRAM (-) CELL WALL
Presence of (Ribitol/Glycerol phosphate) Teichoic and Lipoteichoic acid (Glycerol Teichoic acid)
Gram (+) Cell Wall
GRAM (+) VS GRAM (-) CELL WALL
Presence of Murein Lipoprotein
Gram (-)
GRAM (+) VS GRAM (-) CELL WALL
No periplasm
Gram (+)
GRAM (+) VS GRAM (-) CELL WALL
Periplasmic space
Gram (-) Cell Wall
GRAM (+) VS GRAM (-) CELL WALL
Antigenic polysaccharide
Presence of S-layer
Gram (+)
GRAM (+) VS GRAM (-) CELL WALL
Outer layer: proteins, phospholipids, and
lipopolysaccharides:
- O-antigen
- Core polysaccharide
- Lipid A (endotoxin)
Gram (-)
GRAM (+) VS GRAM (-) CELL WALL
Flagellum is provided only with two basal rings
Gram (+)
G(+)/G(-): Haemophilus influenzae, Neisseria gonorrhoeae and Bordetella pertussis
Gram (-) Cell Wall
Presence of phospholipids similar in the cell membrane
Gram (-) Cell Wall
Presence of Principal Proteins or Major Outer Membrane Proteins such as
○ Porin Proteins
○ Transmembrane Proteins
○ Peripheral proteins
Gram (-) Cell Wall
GRAM (-) CELL WALL
span the outer membrane
Transmembrane Proteins
GRAM (-) CELL WALL
responsible for transmembrane transport of molecules
Peripheral proteins
appear as WEAKLY GRAM POSITIVE
Acid Fast Cell Wall
Possess a waxy layer of mycolic acid bound to the cell wall
○ Seen in Mycobacterium, Nocardia
Acid Fast Cell Wall
Cell membrane of AF organisms are similar to other bacteria except that they possess _________ & ____________
Phosphatidylmannosides (PIM) and Lipoarabinomannan
ORGANISMS THAT LACK CELL WALL
○ Contains sterol in their cell membranes
○ Seen in various shape microscopically
Mycoplasma and Ureaplasma