Cell Structure and Function

Basic Unit: Cells are the smallest units of life, encapsulating all biological processes.
Components:
- Cell Membrane: Semi-permeable barrier that controls entry and exit of substances.
- Cytoplasm: Gel-like fluid within the cell, containing organelles and cytosol.
- Nucleus: Contains genetic material (DNA); regulates cell activities.
- Organelles:
  - Mitochondria: Powerhouse of the cell; energy production through respiration.
  - Ribosomes: Protein synthesis; may be free in cytoplasm or attached to the endoplasmic reticulum.
  - Endoplasmic Reticulum (ER):
    - Rough ER: Studded with ribosomes; synthesizes proteins.
    - Smooth ER: No ribosomes; involved in lipid synthesis and detoxification.
  - Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or use.
  - Lysosomes: Digests worn-out cellular components and foreign materials.
  - Cytoskeleton: Network of fibers for structural support, transport, and movement.

Metabolism: Chemical reactions that occur in the cell to maintain life, including energy production (ATP).
Homeostasis: Maintaining a stable internal environment despite external changes.
Communication: Cells communicate through signals (chemical or electrical) to coordinate functions.
Reproduction: Cells can reproduce via processes like mitosis (for growth and repair) or meiosis (for gamete formation).

Mitosis:
- Process of cell division resulting in two genetically identical daughter cells.
- Stages:
  - Prophase: Chromatin condenses into chromosomes; nuclear envelope breaks down.
  - Metaphase: Chromosomes align at the cell's equator.
  - Anaphase: Sister chromatids are pulled apart to opposite poles.
  - Telophase: Nuclear membranes reform; chromosomes decondense.
  - Cytokinesis: Division of the cytoplasm, resulting in two separate cells.
Meiosis:
- Specialized form of cell division resulting in four genetically varied daughter cells (gametes).
- Stages include two rounds of division (meiosis I and II) with processes such as crossing over that increase genetic variability.
- Essential for sexual reproduction in eukaryotes.

These fundamental concepts establish the basis of understanding cells as the primary units of life in all living organisms.

Basic Unit: The cell is the fundamental unit of life.
Cell Membrane: Controls what enters and exits the cell.
Cytoplasm: Gel-like substance that holds organelles and cytosol.
Nucleus: Contains DNA, the cell's genetic blueprint, and directs cell activity.
Mitochondria: Powerhouse of the cell, produces energy (ATP) through cellular respiration.
Ribosomes: Assemble proteins, and are found free in the cytoplasm or attached to the endoplasmic reticulum.
Endoplasmic Reticulum (ER)
- Rough ER: Studded with ribosomes, synthesizes proteins
- Smooth ER: No ribosomes, produces lipids and detoxifies substances.
Golgi Apparatus: Processes, packages, and delivers proteins and lipids for secretion or use within the cell.
Lysosomes: Responsible for breaking down and digesting worn-out cell parts and foreign materials.
Cytoskeleton: Provides structural support, allows for movement, and assists with transportation within the cell.

Metabolism: Chemical reactions occur within the cell to sustain life, including energy production.
Homeostasis: Cells maintain a stable internal environment despite external fluctuations.
Communication: Cells interact by sending and receiving signals to coordinate functions.
Reproduction: Cells reproduce through mitosis (for growth and repair) or meiosis (for gamete formation).

Mitosis: Division of a parent cell into two genetically identical daughter cells.
- Prophase: Chromatin condenses into chromosomes and the nuclear envelope breaks down.
- Metaphase: Chromosomes line up at the center of the cell.
- Anaphase: Sister chromatids (replicas of a chromosome) are pulled apart and move to opposite poles of the cell.
- Telophase: Nuclear membranes reform around each set of chromosomes, chromosomes uncoil, and the cell begins to divide.
- Cytokinesis: The cytoplasm divides, resulting in two independent daughter cells.
Meiosis: Special type of cell division resulting in four genetically unique gametes (sex cells).
- Involves two rounds of division (meiosis I and II) with key events like crossing over (exchange of genetic material) that increase genetic diversity.
- Essential for sexual reproduction in eukaryotes.