Cell Biology Overview

Cell Biology

Definition: Study of the structure, function, and behavior of cells, the basic unit of life.
Types of Cells:
- Prokaryotic Cells:
  - Lack a nucleus and membrane-bound organelles.
  - Smaller and simpler (e.g., bacteria).
- Eukaryotic Cells:
  - Contain a nucleus and membrane-bound organelles.
  - Larger and more complex (e.g., animal and plant cells).
Cell Structure:
- Plasma Membrane:
  - Semi-permeable barrier that controls the movement of substances in and out.
- Cytoplasm:
  - Gel-like substance where organelles are suspended.
- Nucleus:
  - Contains genetic material (DNA); controls cell activities.
- Mitochondria:
  - Powerhouse of the cell; produces energy (ATP) through respiration.
- Ribosomes:
  - Sites of protein synthesis.
- Endoplasmic Reticulum (ER):
  - Rough ER: Studded with ribosomes; synthesizes proteins.
  - Smooth ER: Lacks ribosomes; synthesizes lipids and detoxifies.
- Golgi Apparatus:
  - Modifies, sorts, and packages proteins and lipids for secretion or delivery.
- Lysosomes:
  - Contains digestive enzymes; breaks down waste materials and cellular debris.
- Centrioles:
  - Involved in cell division.
- Chloroplasts (in plant cells):
  - Site of photosynthesis; contains chlorophyll.
Cell Division:
- Mitosis:
  - Process of cell division that results in two identical daughter cells.
  - Phases: Prophase, Metaphase, Anaphase, Telophase, Cytokinesis.
- Meiosis:
  - Process of cell division that produces gametes (sperm and eggs).
  - Reduces chromosome number by half; involves two rounds of division.
Cell Communication:
- Signaling Molecules:
  - Hormones, neurotransmitters, and other molecules that transmit signals.
- Receptors:
  - Proteins on cell membranes that bind to signaling molecules to initiate a response.
Cell Metabolism:
- Catabolism:
  - Breakdown of molecules to release energy.
- Anabolism:
  - Synthesis of complex molecules from simpler ones using energy.
Cellular Processes:
- Photosynthesis (in plants):
  - Conversion of light energy into chemical energy (glucose) using carbon dioxide and water.
- Cellular Respiration:
  - Process of converting glucose and oxygen into energy (ATP), carbon dioxide, and water.
Cell Theory:
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Techniques in Cell Biology:
- Microscopy:
  - Techniques like light microscopy and electron microscopy to visualize cells.
- Cell Culture:
  - Growing cells in a controlled environment for research and experimentation.
Applications:
- Medical research (cancer, genetic disorders).
- Biotechnology (gene editing, stem cell research).
- Environmental science (bioremediation).

Overview of Cell Biology

Focuses on the structure, function, and behavior of cells, the fundamental units of life.

Types of Cells

Prokaryotic Cells:
- No nucleus or membrane-bound organelles; examples include bacteria.
- Generally smaller and simpler in structure.
Eukaryotic Cells:
- Possess a nucleus and membrane-bound organelles; found in animals and plants.
- Larger and more complex than prokaryotic cells.

Key Cell Structures

Plasma Membrane:
- Semi-permeable barrier regulating the entry and exit of substances.
Cytoplasm:
- Gel-like medium where organelles are suspended.
Nucleus:
- Houses genetic material (DNA) and directs cell activities.
Mitochondria:
- Known as the powerhouse of the cell, responsible for ATP production via respiration.
Ribosomes:
- Sites specialized in protein synthesis.
Endoplasmic Reticulum (ER):
- Rough ER: Studded with ribosomes, involved in protein synthesis.
- Smooth ER: Lacks ribosomes, synthesizes lipids and detoxifies harmful substances.
Golgi Apparatus:
- Modifies, sorts, and packages proteins and lipids for secretion and delivery.
Lysosomes:
- Contain digestive enzymes for waste breakdown and cellular debris disposal.
Centrioles:
- Facilitate cell division.
Chloroplasts (in plant cells):
- Site of photosynthesis, containing chlorophyll for light energy conversion.

Cell Division

Mitosis:
- Produces two identical daughter cells; consists of phases such as Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.
Meiosis:
- Creates gametes (sperm and eggs); reduces chromosome count by half, involves two cycles of division.

Cell Communication

Signaling Molecules:
- Include hormones and neurotransmitters that convey signals between cells.
Receptors:
- Membrane proteins that react to signaling molecules, triggering cellular responses.

Cell Metabolism

Catabolism:
- The process of breaking down molecules to release energy for cellular functions.
Anabolism:
- The synthesis of complex molecules from simpler ones, utilizing energy.

Cellular Processes

Photosynthesis (in plants):
- Converts light energy into chemical energy (glucose) using carbon dioxide and water.
Cellular Respiration:
- Transforms glucose and oxygen into energy (ATP), releasing carbon dioxide and water as byproducts.

Cell Theory

Asserts that:
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.

Techniques in Cell Biology

Microscopy:
- Employs light and electron microscopy for cell visualization.
Cell Culture:
- Involves growing cells in controlled environments for experimental purposes.

Applications

Medical Research:
- Focuses on conditions like cancer and genetic disorders.
Biotechnology:
- Engages in gene editing and stem cell research.
Environmental Science:
- Uses bioremediation techniques for environmental restoration.