Microbiology: Bacteria Basics

Types of bacteria:
- Gram-positive: thick peptidoglycan layer, retain crystal violet stain
- Gram-negative: thin peptidoglycan layer, don't retain crystal violet stain
- Acid-fast: resist decolorization, e.g. Mycobacterium tuberculosis
Bacterial shapes:
- Spherical (cocci)
- Rod-shaped (bacilli)
- Spiral (spirochetes)
- Comma-shaped (vibrios)
Bacterial reproduction:
- Binary fission: asexual reproduction, results in two identical cells
- Sporulation: formation of highly resistant spores

Viral structure:
- Capsid: protein coat that surrounds the viral genome
- Genome: DNA or RNA that contains the viral genetic material
- Envelope: lipid bilayer that surrounds the capsid
Viral replication:
- Attachment: virus binds to host cell
- Penetration: virus enters host cell
- Uncoating: viral genome is released from capsid
- Replication: viral genome is replicated
- Assembly: new viral particles are assembled
- Release: new viral particles are released from host cell
Types of viruses:
- DNA viruses: e.g. herpesviruses, adenoviruses
- RNA viruses: e.g. influenza, HIV

Immune system:
- Innate immunity: non-specific defense against pathogens
- Adaptive immunity: specific defense against pathogens
Types of immune cells:
- Phagocytic cells: e.g. neutrophils, macrophages
- Lymphocytes: e.g. B cells, T cells
Immune response:
- Activation of immune cells
- Production of antibodies
- Elimination of pathogens

Types of parasites:
- Protozoa: e.g. Plasmodium, Giardia
- Helminths: e.g. nematodes, trematodes, cestodes
- Ectoparasites: e.g. ticks, fleas, lice
Parasite life cycles:
- Direct transmission: parasite is transmitted directly from one host to another
- Indirect transmission: parasite requires an intermediate host or vector
Parasite-host interactions:
- Adhesion: parasite attaches to host cell
- Invasion: parasite enters host cell
- Evasion: parasite evades host immune response

Classification: Bacteria are classified based on Gram staining, which differentiates between Gram-positive and Gram-negative bacteria.
Cell wall composition: Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin peptidoglycan layer.
Acid-fast bacteria: Mycobacterium tuberculosis is an example of an acid-fast bacterium, which resists decolorization.
Shapes: Bacteria can be spherical (cocci), rod-shaped (bacilli), spiral (spirochetes), or comma-shaped (vibrios).
Reproduction: Bacteria reproduce through binary fission, an asexual process that results in two identical cells.
Sporulation: Bacteria can form highly resistant spores through sporulation.

Viral structure: A virus consists of a capsid (protein coat), genome (DNA or RNA), and sometimes an envelope (lipid bilayer).
Viral replication: The replication process involves attachment, penetration, uncoating, replication, assembly, and release.
Viral types: Viruses can be classified as DNA viruses (e.g., herpesviruses, adenoviruses) or RNA viruses (e.g., influenza, HIV).

Immune system: The immune system consists of innate immunity (non-specific defense) and adaptive immunity (specific defense).
Immune cells: Phagocytic cells (e.g., neutrophils, macrophages) and lymphocytes (e.g., B cells, T cells) are types of immune cells.
Immune response: The immune response involves the activation of immune cells, production of antibodies, and elimination of pathogens.

Parasite classification: Parasites can be classified as protozoa (e.g., Plasmodium, Giardia), helminths (e.g., nematodes, trematodes, cestodes), or ectoparasites (e.g., ticks, fleas, lice).
Life cycles: Parasites can have direct transmission (from one host to another) or indirect transmission (requiring an intermediate host or vector).
Parasite-host interactions: Parasites can adhere to host cells, invade host cells, and evade the host immune response.