4- Biología celular. Características comunes de todos los seres vivos
Introduction to Biological Phenomena
Overview of Living Organisms
- The session focuses on the characteristics that define living beings, following a previous discussion on the organization of matter.
- All living organisms share common characteristics; they must fulfill these criteria to be classified as living entities.
Cellular Composition
- Living beings are composed of at least one cell, which is the basic unit of life.
- There are unicellular organisms (single-celled) and multicellular organisms (composed of many cells), each with various types of cells.
Organization and Complexity
- Living beings exhibit organization and complexity in their cellular structures, arising from different levels of material organization.
- They are classified as open systems capable of exchanging matter and energy with their environment.
Metabolism
- Metabolism encompasses all biochemical reactions within a cell, including anabolic (building up) and catabolic (breaking down) processes.
- This metabolic activity is essential for survival, allowing cells to synthesize components and degrade molecules for nourishment.
Homeostasis in Living Beings
Importance of Homeostasis
- Homeostasis refers to the ability to maintain a stable internal environment, crucial for metabolic reactions that require specific pH and temperature ranges.
Example of Homeostasis
- An example is sweating: it cools the body by evaporating sweat from the skin, helping regulate internal temperature.
Additional Characteristics of Life
Responsiveness and Growth
- Living organisms demonstrate habitability by responding to external or internal stimuli; they grow and develop over time.
Reproduction and Evolution
- They reproduce, producing offspring with similar physiological and morphological traits. Adaptations can lead to evolution if beneficial traits are inherited across generations.
Autopoiesis
- Autopoiesis describes an organism's ability to self-produce its components; for instance, a single bacterium can replicate itself entirely.
Conclusion on Characteristics