Bacteria Flashcards
Chapter1
What are bacteria?
Microscopic, single-celled organisms that exist in various environments and play vital roles in life processes.
How do bacteria obtain energy?
Through photosynthesis, chemosynthesis (autotrophs), or by consuming organic material (heterotrophs).
Who first classified bacteria based on shape
Ferdinand Cohn’s (1872)
Monococcus (Mircococcus)
Represented by a single discrete round
ex: Micrococcus flavus
Diplococcus
The cells of the diplococcus divides in a particular plain and remain attached after division
ex: Diplococcus pneumonia
Streptococcus
The cells divide repeatedly in one plane to form a chain of cells
ex: Streptococcus pyogenes
Tetracoccus
Consist of four round cells, which are defined in two planes at right angles to one another
ex Gaffkya tetragena
Staphylococcus
The cells divide into three planes forming an irregular configuration, like grapes
ex: Staphylococcus aureus
Sarcina
The cells divide in three planes but they form a cube like configuration consisting of eight or sixteen cells
Bacilli
Rod shaped or cylindrical bacteria
ex: Bacillus cereus
Vibrio
Curved, comma-shaped bacteria
ex: Vibrio cholerae
What are Sprillia?
Spiral or spring-like with multiple curvature and terminal flagella
ex: Spiralium volutans
Gram-Positive Bacteria: Cell Wall Structure
-Thick Peptidoglycan Layer
-Teichoic and Lipoteichoic Acids
-No Outer Membrane
-can be broken down mechanically
Gram-Negative Bacteria: Cell Wall Structure
-Thin Peptidoglycan Layer
-Outer Membrane consisting of lipopolysaccharides (LPS) lipoproteins, and phospholipids
-Periplasmic Space
-Cannot be broken done mechanically
Gram-Positive Bacteria: Gram Staining
Retain the crystal violet dye during Gram staining, appearing purple under the microscope.
Gram-Negative Bacteria: Gram Staining
Do not retain the crystal violet dye and are counterstained with safranin, appearing pink/red under the microscope.
Gram-Positive Bacteria: Antibiotics
Generally more sensitive to antibiotics like penicillin and vancomycin due to the exposed peptidoglycan layer.
Gram-Negative Bacteria: Antibiotics
Often more resistant to antibiotics because the outer membrane acts as a barrier to many drugs.
Gram-Positive Bacteria: EX
-Staphylococcus aureus:
-Streptococcus pyogenes:
-Clostridium botulinum:
Gram-Negative Bacteria: EX
-Escherichia coli (E. coli):
-Pseudomonas aeruginosa:
-Neisseria gonorrhoeae:
How do bacteria respond to oxygen?
-Aerobic (require oxygen)
ex: Pseudomonas
-Anaerobic (no oxygen)
ex: Clostridium botulinum
-Facultative anaerobes (either condition).
ex: Staphylococcus aureus
What are extremophiles?
Bacteria that thrive in extreme conditions (e.g., high temperature, acidity, or salinity).
What are halophiles?
Salt-loving bacteria found in saline environments.
ex: Halococcus
What are thermophiles?
Can live in high temperatures, up to 75 to 80°C
ex: Streptococcus thermophiles
