Cell Biology Basics

Cell Theory:
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Types of Cells:
- Prokaryotic Cells:
  - No nucleus or membrane-bound organelles.
  - Smaller and simpler (e.g., bacteria).
- Eukaryotic Cells:
  - Nucleus and membrane-bound organelles.
  - Larger and more complex (e.g., plant and animal cells).

Cell Membrane:
- Semi-permeable barrier that controls the movement of substances in and out of the cell.
- Composed of a phospholipid bilayer with embedded proteins.
Nucleus:
- Contains genetic material (DNA).
- Controls cell activities and gene expression.
Cytoplasm:
- Jelly-like substance where cellular processes occur.
- Contains organelles and cytosol.
Organelles:
- Mitochondria: Powerhouse of the cell, site of ATP (energy) production.
- Ribosomes: Sites of protein synthesis.
- Endoplasmic Reticulum (ER):
  - Rough ER: Studded with ribosomes, involved in protein synthesis and processing.
  - Smooth ER: Lacks ribosomes, involved in lipid synthesis and detoxification.
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for transport.
- Lysosomes: Contain enzymes for digestion and waste processing.
- Chloroplasts (in plant cells): Site of photosynthesis.

Mitosis:
- Process of cell division resulting in two identical daughter cells.
- Stages: Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.
Meiosis:
- Process of cell division that produces gametes (sperm and eggs).
- Involves two rounds of division, resulting in four non-identical cells.

Metabolism:
- Sum of all chemical reactions occurring within the cell, including catabolism (breaking down molecules) and anabolism (building up molecules).
Cellular Respiration:
- Process of converting glucose and oxygen into ATP, carbon dioxide, and water.
- Stages include Glycolysis, Krebs Cycle, and Electron Transport Chain.
Photosynthesis (in plants):
- Process by which chloroplasts convert light energy into chemical energy in the form of glucose.
- Equation: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.

Signal Transduction:
- Process by which cells respond to external signals (hormones, nutrients).
- Involves receptors on the cell membrane and a cascade of internal signaling pathways.
Cell Adhesion:
- Cells attach to each other and to the extracellular matrix, crucial for tissue formation and function.

Stem Cells: Undifferentiated cells capable of developing into various cell types.
Muscle Cells: Specialized for contraction and movement.
Neurons: Specialized for transmitting signals in the nervous system.

Microscopy:
- Techniques such as light microscopy and electron microscopy used to visualize cells and their components.
Cell Culture:
- Growing cells in controlled conditions for research and experimentation.
Molecular Biology Techniques:
- Techniques such as PCR, gel electrophoresis, and DNA sequencing used to study genetic material within cells.

Cell Theory: Comprises three main tenets; all living organisms consist of cells, the cell is the fundamental unit of life, and all cells originate from pre-existing cells.
Prokaryotic Cells: Characterized by the absence of a nucleus and membrane-bound organelles; typically smaller and simpler, exemplified by bacteria.
Eukaryotic Cells: Feature a distinct nucleus and membrane-bound organelles; larger and more complex, including plant and animal cells.

Cell Membrane: Functions as a semi-permeable barrier regulating substance movement; structured as a phospholipid bilayer interspersed with proteins.
Nucleus: Houses genetic material (DNA); orchestrates cellular activities and gene expression.
Cytoplasm: A viscous, jelly-like substance facilitating cellular processes; contains cytosol and organelles.
Organelles:
- Mitochondria: Known as the powerhouse of the cell; crucial for ATP (energy) production.
- Ribosomes: Sites dedicated to protein synthesis.
- Endoplasmic Reticulum (ER): Divided into Rough ER (with ribosomes, involved in protein synthesis) and Smooth ER (lacks ribosomes, engaged in lipid synthesis and detoxification).
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for cellular transport.
- Lysosomes: Contain digestive enzymes for breaking down waste and cellular debris.
- Chloroplasts: Present in plant cells; the site of photosynthesis.

Mitosis: A process resulting in two genetically identical daughter cells; includes stages: Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.
Meiosis: Specialized division producing gametes (sperm and eggs); consists of two divisions yielding four non-identical cells.

Metabolism: Encompasses all chemical reactions within a cell, categorized into catabolism (breaking down molecules) and anabolism (building up molecules).
Cellular Respiration: Converts glucose and oxygen into ATP, carbon dioxide, and water; involves Glycolysis, Krebs Cycle, and Electron Transport Chain.
Photosynthesis: In plants, chloroplasts convert light energy into glucose; described by the equation 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.

Signal Transduction: Mechanism for cells to respond to external signals (hormones, nutrients) through membrane receptors and internal signaling cascades.
Cell Adhesion: Critical for tissue formation; involves cells binding to each other and the extracellular matrix.

Stem Cells: Unspecialized cells with the potential to develop into various cell types.
Muscle Cells: Adapted for contraction, enabling movement.
Neurons: Specialize in transmitting electrical signals throughout the nervous system.

Microscopy: Includes light and electron microscopy for visualizing cells and their components.
Cell Culture: Involves growing cells under controlled conditions for research purposes.
Molecular Biology Techniques: Encompasses methods like PCR, gel electrophoresis, and DNA sequencing for analyzing genetic material.