Bacterial Cell Structure

Cell Wall

• Present in most bacteria, but not in some species like Mycoplasma
• Composed of peptidoglycan (also known as murein), a thick layer of polysaccharide chains cross-linked by short peptides
• Provides structural support and maintains cell shape
• Helps to maintain osmotic balance and prevents cell lysis
• Can be Gram-positive or Gram-negative, depending on the type of peptidoglycan and the presence of additional layers

Cytoplasm

• A gel-like substance inside the cell membrane
• Composed of water, salts, sugars, and various organic compounds
• Contains the cell's genetic material (DNA), ribosomes, and various metabolic pathways
• Site of many cellular activities, such as glycolysis, protein synthesis, and cell division
• Can be differentiated into various regions, such as the nucleoid (where DNA is located) and the cytosol (where metabolic reactions occur)

Plasma Membrane

• A thin, semi-permeable membrane that surrounds the cell and regulates the flow of materials in and out
• Composed of a phospholipid bilayer with embedded proteins
• Maintains cellular homeostasis by controlling the movement of ions, nutrients, and waste products
• Involved in various cellular processes, such as cell signaling, transport, and secretion
• Can be selectively permeable to allow certain substances to pass through while keeping others out

Ribosomes

• Small, complex organelles found throughout the cytoplasm
• Composed of rRNA and proteins
• Site of protein synthesis, where mRNA is translated into amino acid chains
• Can be free in the cytoplasm or attached to the plasma membrane
• Found in large numbers in cells that are actively synthesizing proteins, such as during rapid growth or division