Micro| 3.01 Bacteria Basics

3.01 Bacteria Basics Microbio review for the USMLE Step 1 Exam: Bacteria are single-celled organisms that can cause infection Structural components of bacteria include: capsule, cell wall, flagella, fimbriae, plasma membrane, ribosomes, endospores, and DNA Capsules help bacteria evade the immune system by inhibiting phagocytes Flagella are tail-like appendages that allow bacteria to move, fimbriae help bacteria adhere to surfaces Most bacteria have a cell wall, which can be either gram positive or gram negative Plasma membrane is composed of proteins and phospholipids and performs various functions DNA is the genetic material, ribosomes are used to build proteins, some bacteria have endospores which are heat-resistant resting cells Bacteria can be classified by cell wall composition, morphology, metabolism, and based on their ability to grow at different temperatures and pH levels Gram staining is a laboratory technique used to differentiate between gram positive and gram negative bacteria Morphology of bacteria includes cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped) Metabolism of bacteria can be aerobic (uses oxygen) or anaerobic (doesn't use oxygen) Temperature and pH ranges at which bacteria can grow vary widely, some can grow at extreme conditions Pathogenic bacteria cause disease, while non-pathogenic bacteria do not Bacteria can be treated with antibiotics, but overuse can lead to antibiotic resistance