Bacteria Structure And Function Flashcards
What are the two main types of bacterial cell walls?
Gram-positive and Gram-negative
What separates the inner and outer cell walls in Gram-negative bacteria?
Periplasmic space
What is the primary component of the Gram-positive bacterial cell wall?
Peptidoglycan layer
What additional substances can be found in the Gram-positive cell wall?
- Teichoic acid
- Teichuronic acid
- Various polysaccharides
What is the function of the cell membrane in bacteria?
- Selective permeability
- Electron transport chain in energy generation
- Receptor site for antigen binding
- Location of enzymes
- Mitosis
What does peptidoglycan provide to bacterial cells?
- Shape
- Rigidity
- High osmotic pressure maintenance
What is the composition of the cytoplasm in bacteria?
- Ribosomes
- Granules (glycogen, starch, sulfur, fat, polyphosphate)
- Enzymes (hydrolytic, polymerases)
- Water and ions
- Macromolecules (lipids, structural proteins, carbohydrates)
What is the ribosome size in bacteria?
70S
What are the two subunits of bacterial ribosomes?
- 50S
- 30S
What is the shape of bacterial nucleoid?
Scattered throughout the cytoplasm
What type of DNA do eubacteria possess?
Double stranded circular DNA in haploid form
What is the role of DNA gyrase in bacteria?
Keeps DNA in supercoiled state
What distinguishes Gram-negative bacteria from Gram-positive bacteria?
Thinner peptidoglycan layer and presence of periplasmic space
What are the components of the bacterial flagella?
- Basal body
- Hook
- Filament
What is the function of pili in bacteria?
Attachment and conjugation
What is endotoxin primarily composed of?
Lipid A (part of lipopolysaccharides)
What type of bacteria produce exotoxins?
Both Gram-positive and Gram-negative organisms
What is a capsule in bacterial cells?
A well-defined layer external to the cell wall, composed of polysaccharides or polypeptides
What is the difference between a protoplast and a spheroplast?
- Protoplast: Gram-positive bacteria with loss of cell wall
- Spheroplast: Gram-negative bacteria with loss of cell wall
Which bacteria are known for forming spores?
- Clostridium spp.
- Bacillus anthracis
What are Mycoplasmas?
Cell wall-less bacteria
What are the major categories of pathogenic bacteria?
- Gram-negative bacteria with cell walls
- Gram-positive bacteria with cell walls
- Cell wall-less bacteria
- Archaeobacteria
What is the significance of the high osmotic pressure in bacteria?
It necessitates a rigid cell wall to prevent osmotic lysis
Fill in the blank: The cell membrane is composed of a _______.
Lipid bilayer
