Scientists use a Gram stain to classify them. Gram-positive bacteria have a thick peptidoglycan layer that retains purple dye, while Gram-negative bacteria have a thinner layer and an outer membrane, appearing pink.
Engineered bacteria produce insulin, vaccines, and enzymes used in detergents. 4. Human Health and the Microbiome bacterium
Many use flagella for movement or pili to adhere to surfaces or exchange genetic material. 2. Reproduction and Growth Scientists use a Gram stain to classify them
The human body is home to trillions of bacteria, known as the . These "good" bacteria aid in digestion and protect against harmful pathogens. However, pathogenic bacteria cause diseases such as strep throat, tuberculosis, and urinary tract infections. These are typically treated with antibiotics , though the overuse of these drugs has led to the rise of "superbugs"—bacteria that are resistant to standard medical treatments. Reproduction and Growth The human body is home
Bacteria are microscopic, single-celled organisms that exist in virtually every environment on Earth, from deep-sea vents to the human digestive tract. They are , meaning they lack a nucleus and membrane-bound organelles. While often associated with disease, the vast majority of bacteria are either harmless or essential to life. 1. Structure and Classification
They break down organic matter, recycling carbon and nutrients back into the ecosystem.
Common forms include cocci (spherical), bacilli (rod-shaped), and spirilla (spiral).