Cell Biology Overview

Study Notes

Cell Biology

Definition: Cell biology is the study of cells, their physiological properties, structures, organelles, interactions, and behavior.
Types of Cells:
- Prokaryotic Cells:
  - Lack a nucleus and membrane-bound organelles.
  - Generally 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).
Basic Cell Structures:
- Cell Membrane:
  - Phospholipid bilayer that controls the movement of substances in and out of the cell.
- Cytoplasm:
  - Jelly-like substance where cellular processes occur, containing organelles.
- Nucleus:
  - Contains genetic material (DNA) and regulates gene expression and cell division.
- Mitochondria:
  - Powerhouse of the cell, involved in energy (ATP) production through respiration.
- Ribosomes:
  - Sites of protein synthesis; can be free-floating or attached to the endoplasmic reticulum.
- Endoplasmic Reticulum (ER):
  - Rough ER: Studded with ribosomes; synthesizes proteins.
  - Smooth ER: Lacks ribosomes; synthesizes lipids and detoxifies drugs.
- Golgi Apparatus:
  - Modifies, sorts, and packages proteins and lipids for secretion or use within the cell.
- Lysosomes:
  - Contain digestive enzymes to break down waste materials and cellular debris.
- Chloroplasts:
  - Found in plant cells; site of photosynthesis, converting sunlight into chemical energy.
Cell Functions:
- Metabolism: All biochemical reactions occurring within the cell.
- Protein Synthesis: The process of translating genetic information into proteins.
- Cell Division:
  - Mitosis: Division of somatic cells for growth and repair.
  - Meiosis: Division of germ cells for sexual reproduction.
Cell Communication:
- Cells communicate through chemical signals (hormones, neurotransmitters) and receptors on the cell membrane.
Cell Theory:
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.

Cell Biology Overview

Cell biology studies cells, examining their properties, structures, organelles, interactions, and functions.

Types of Cells

Prokaryotic Cells:
- Lack a nucleus and membrane-bound organelles.
- Typically smaller and simpler, exemplified by bacteria.
Eukaryotic Cells:
- Possess a nucleus and membrane-bound organelles.
- Generally larger and more complex, including plant and animal cells.

Basic Cell Structures

Cell Membrane:
- Composed of a phospholipid bilayer, it regulates substance movement in and out of the cell.
Cytoplasm:
- Jelly-like matrix where cellular processes occur and organelles are suspended.
Nucleus:
- Houses genetic material (DNA), regulates gene expression, and controls cell division.
Mitochondria:
- Known as the powerhouse of the cell, crucial for ATP production through respiration.
Ribosomes:
- Sites for protein synthesis; can be found free in cytoplasm or attached to the endoplasmic reticulum.
Endoplasmic Reticulum (ER):
- Rough ER: Covered with ribosomes, involved in protein synthesis.
- Smooth ER: Lacks ribosomes, responsible for lipid synthesis and drug detoxification.
Golgi Apparatus:
- Modifies, sorts, and packages proteins and lipids for secretion or internal use.
Lysosomes:
- Contain digestive enzymes for breaking down waste and debris.
Chloroplasts:
- Present in plant cells; sites of photosynthesis, converting sunlight into chemical energy.

Cell Functions

Metabolism:
- Refers to all biochemical reactions that occur within the cell.
Protein Synthesis:
- Process of translating genetic information into functional proteins.
Cell Division:
- Mitosis: Somatic cell division for growth and repair.
- Meiosis: Germ cell division to produce gametes for sexual reproduction.

Cell Communication

Cells utilize chemical signals (like hormones and neurotransmitters) and membrane receptors for communication.

Cell Theory

All living organisms are composed of cells.
The cell is the fundamental unit of life.
Cells originate from pre-existing cells.

Description

Explore the fascinating world of cell biology, focusing on the definition, types of cells, and basic structures essential for life. Understand the differences between prokaryotic and eukaryotic cells, and discover the roles of various organelles like mitochondria and ribosomes.