Organismo: Structura e Organization

Study Notes

Living organisms exist as single-celled or multicellular. Multicellular organisms are more structurally complex.
Key structural levels are:
- Chemical: Basic components of cells (atoms and molecules). These don't perform life functions.
- Cellular: The fundamental unit of life. It carries out life functions such as reproduction, interaction, and nutrition.
- Tissue: Groups of cells with similar function and structure performing specialized roles
- Organ: Groups of tissues working together to conduct complex functions
- Systems/Apparatuses: Organized groups of organs working toward a common goal. These are further subdivided into organ systems, including musculoskeletal, circulatory, endocrine, etc., and also organ apparatuses, including digestive, urinary, respiratory, reproductive, cardiovascular, and locomotor.

Cells are the basic unit of life, carrying out life processes
Prokaryotic Cells:
- Lacks a defined nucleus.
- Genetic material (DNA) is free-floating in the cytoplasm.
- Bacteria are examples of prokaryotic cells.
Eukaryotic Cells:
- Possess a defined nucleus with a membrane separating it from the cytoplasm.
- Have various membrane-bound organelles (e.g., mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus).

All cells share basic structures: plasma membrane, cytoplasm, and genetic material (DNA).
Plasma membrane: A phospholipid bilayer with embedded proteins that controls substance passage into and out of the cell.
Cytoplasm: The gel-like substance within the cell, containing organelles and dissolved substances.
Genetic material/DNA: Guides cell activities, located in the nucleus of eukaryotic cells.

Cells perform specific functions related to nutrition, interaction, and reproduction.
Nutrition: Intake of nutrients from the environment for energy and growth.
Interaction: Responding to external stimuli and interacting with other cells.
Reproduction: Creating new cells (mitosis for growth and repair; meiosis for sexual reproduction).

Organs are structures comprising of different tissue types, having a specific function.
Organs are often composed of several different tissue types that function together

Biological systems are composed of multiple organs that work together toward a shared purpose.
Major body systems include the circulatory, digestive, nervous, urinary, and other systems.