cap 1 (libro)

• Microorganisms are Earth's life support system
• Microbes influence nearly every moment of our lives
• Microbes are found in water, food, and on and in us
• Microbes can thrive in environments too hostile for higher life forms
• Microbiology allows us to explore the microbial world
• Microbiology evolves rapidly
• Microscopy continues to evolve, providing detailed images of the microbial world
• Fluorescence microscopy uses lasers to map the three-dimensional structure of cells
• Listeria monocytogenes is a foodborne bacterial pathogen that can infect human cells
• Listeria can hijack cellular systems, causing actin to propel the cell within the host cytoplasm
• Listeria can penetrate adjacent cells, spreading the infection
• Listeria can also hide and survive in host vacuoles
• Research on Listeria provides insights into the biology of this pathogen and the microbial world
• Microorganisms are microscopic organisms with diverse forms and functions
• Microorganisms inhabit every environment on Earth that supports life
• Microorganisms can be single-celled or form complex structures
• Microorganisms typically live in microbial communities and interact with their environments and other organisms
• Microorganisms have been on Earth for billions of years and are essential for sustaining life
• Microbiology studies microorganisms, their functions, and their impact on the planet and living organisms
• Microbiologists use microscopy and microbial cultivation to study microorganisms
• Microbial culture is a collection of cells grown in a nutrient medium
• Growth refers to the increase in cell number as a result of cell division
• Microbial colonies form when a single cell grows and divides into millions or billions of cells
• Microorganisms play a major role in human life, affecting health, food, water, soil fertility, and more
• Microbial activities are essential for sustaining life and driving survival and reproduction
• All cells have a cytoplasmic membrane, ribosomes, and a genome
• Cells may have a cell wall for structural strength
• Prokaryotic cells lack a nucleus and organelles, while eukaryotic cells have membrane-enclosed organelles
• Genes encode proteins that regulate cellular processes
• Enzymes carry out reactions within the cell to supply energy and perform biosynthesis
• Gene expression involves transcription and translation to synthesize proteins
• Microbial growth requires DNA replication followed by cell division
• Microorganisms can sense and respond to changes in their environment
• Motility allows microbial cells to relocate in response to environmental conditions
• Differentiation in microbial cells may occur based on environmental cues
• Bacteria and Archaea typically have small and compact genomes, containing between 500 and 10,000 genes encoded by 0.5 to 10 million base pairs of DNA
• Eukaryotic cells have larger and less streamlined genomes than prokaryotic cells
• A human cell contains approximately 3 billion base pairs, encoding about 20,000–25,000 genes
• All cells have a cytoplasmic membrane, cytoplasm, a genome made of DNA, and ribosomes
• Some cells are capable of self-propulsion