baktérias

Baktérias are single-celled microorganisms that are found in virtually every environment on Earth. They are prokaryotes, meaning their cells lack a nucleus and other membrane-bound organelles. Baktérias vary greatly in size and shape, but are typically measured in micrometers. They can be rod-shaped (bacilli), spherical (cocci), or spiral (spirilla).

Baktérias reproduce asexually, most commonly through binary fission, where one cell divides into two identical daughter cells. This rapid reproduction rate allows populations to grow exponentially. Their metabolic diversity is also remarkable, with some baktérias producing energy from sunlight (photosynthesis), others from chemical compounds (chemosynthesis), and many obtaining nutrients from organic matter.

While many people associate baktérias with disease, the vast majority are harmless or even beneficial. Many play crucial roles in ecosystems, such as decomposing dead organic matter, cycling nutrients like nitrogen and carbon, and serving as the base of food webs. In humans and animals, symbiotic baktérias in the gut aid digestion and produce essential vitamins.

However, some baktérias are pathogenic, causing infections and diseases by invading tissues, producing toxins, or triggering harmful immune responses. Examples include Streptococcus pneumoniae, which can cause pneumonia, and Escherichia coli, some strains of which can cause food poisoning. Understanding baktérias, both their beneficial and harmful aspects, is vital for medicine, agriculture, and environmental science.