Microbiology: Prokaryotic Cell Structure

Microbiology Basics

• Microbiology is the study of microorganisms, which are tiny, often single-celled organisms.
• Microorganisms play crucial roles in various environments, including human health, ecology, and industry.

Prokaryotic Cells (Bacteria and Archaea)

• Cell Wall: rigid, outermost layer that maintains cell shape and provides protection.
• Plasma Membrane: semi-permeable membrane that regulates the flow of substances in and out of the cell.
• Cytoplasm: jelly-like substance where metabolic processes occur.
• Nucleoid: region where genetic material is found, but lacks a true nucleus.
• Ribosomes: site of protein synthesis.
• Flagella: whip-like structures used for movement.
• Pili and Fimbriae: hair-like structures used for attachment and DNA transfer.
• Plasmids: small, self-replicating circular DNA molecules that can be exchanged between cells.

Eukaryotic Cells (Fungi, Protozoa, Algae)

• Cell Wall: varies in composition and function depending on the organism.
• Plasma Membrane: similar to prokaryotic cells, regulates the flow of substances in and out of the cell.
• Cytoplasm: similar to prokaryotic cells, where metabolic processes occur.
• Nucleus: membrane-bound organelle that contains genetic material.
• Ribosomes: site of protein synthesis.
• Endoplasmic Reticulum (ER): network of membranous tubules and cisternae involved in protein synthesis and transport.
• Golgi Apparatus: complex of flattened sacs and tubules involved in protein modification and transport.
• Mitochondria: site of cellular respiration.
• Chloroplasts (in algae): site of photosynthesis.
• Lysosomes: membrane-bound organelles containing digestive enzymes.
• Cytoskeleton: network of filaments that provides structural support and shape.

Key Functional Processes

• Metabolism: conversion of energy and nutrients into cellular components.
• Reproduction: process by which microorganisms produce new cells.
• Genetic Variation: changes in genetic material that occur through mutation, gene transfer, and recombination.
• Response to Environment: adaptation to changes in temperature, pH, and other environmental factors.