Cell Structure and Function

Study Notes

Basic Unit: Cells are the smallest units of life.
Components:
- Cell Membrane: Semi-permeable barrier that regulates entry and exit of substances.
- Cytoplasm: Gel-like substance where cellular processes occur, containing organelles.
- Nucleus: Contains genetic material (DNA); controls cell activities.
- Organelles: Specialized structures (e.g., mitochondria, ribosomes, endoplasmic reticulum) that perform distinct functions.

Metabolism: All chemical reactions within the cell, including energy production and synthesis of molecules.
Homeostasis: Maintaining stable internal conditions (e.g., temperature, pH).
Growth and Repair: Cells grow and replace damaged or dead cells.
Reproduction: Cells can replicate to create new cells (asexual reproduction in unicellular organisms).

Three Main Principles:
1. All living organisms are composed of one or more cells.
2. The cell is the basic unit of life in all living things.
3. All cells arise from pre-existing cells through cell division.

Prokaryotic Cells:
- Lack a nucleus and membrane-bound organelles.
- Smaller and simpler (e.g., bacteria).
Eukaryotic Cells:
- Have a nucleus and membrane-bound organelles.
- Larger and more complex (e.g., plant and animal cells).
Specialized Cells: Different types of eukaryotic cells (e.g., muscle cells, nerve cells) tailored for specific functions.

Purpose: Allows for growth, repair, and reproduction of organisms.
Types:
- Mitosis: Process of cell division that results in two identical daughter cells; used for growth and repair.
  - Phases: Prophase, Metaphase, Anaphase, Telophase.
- Meiosis: Specialized form of division that produces gametes (sperm and egg cells) with half the number of chromosomes; crucial for sexual reproduction.
  - Involves two rounds of division: Meiosis I and Meiosis II.

Cells are the smallest functional and structural units of life.
The Cell Membrane is a semi-permeable barrier, controlling the movement of substances in and out of the cell.
Cytoplasm is a gel-like substance where various cellular processes take place and houses organelles.
The Nucleus holds the genetic material (DNA) and regulates cell activities.
Organelles are specialized structures like mitochondria (energy production), ribosomes (protein synthesis), and endoplasmic reticulum (synthesis and transport of molecules).

Metabolism encompasses all chemical processes happening within the cell, including energy production and molecule synthesis.
Homeostasis is the ability to maintain stable internal conditions such as temperature and pH levels.
Cells grow, repair, and replace damaged or dead cells as part of their life cycle.
Reproduction involves cell replication, particularly in unicellular organisms which reproduce asexually.

Cell theory consists of three essential principles:
- All living organisms are made up of one or more cells.
- The cell is recognized as the fundamental unit of life across all living things.
- All cells arise from pre-existing cells through the process of cell division.

Prokaryotic Cells are simpler and smaller, lacking a nucleus and membrane-bound organelles, commonly exemplified by bacteria.
Eukaryotic Cells are larger and more complex, containing a nucleus and membrane-bound organelles; examples include plant and animal cells.
Specialized Cells are various types of eukaryotic cells, such as muscle and nerve cells, each designed for specific functions within the organism.

Cell division is essential for organismal growth, repair, and reproduction.
Mitosis results in two identical daughter cells, crucial for growth and tissue repair, comprising phases such as Prophase, Metaphase, Anaphase, and Telophase.
Meiosis is a specialized division process creating gametes with half the chromosome number, essential for sexual reproduction, involving two rounds of division known as Meiosis I and Meiosis II.