Cell Biology Fundamentals: Structure, Function, and Division
English with a size of 4.84 KBCell Theory Fundamentals
- All living things are composed of one or more cells.
- The cell is the basic unit of life.
- All cells originate from pre-existing cells.
Types of Cells
- Prokaryotic Cells
- Simple structure, lack a nucleus, and contain no membrane-bound organelles (e.g., bacteria).
- Eukaryotic Cells
- Complex structure, possess a nucleus and various organelles (e.g., plant and animal cells).
Cell Organelles: Structure and Function
Organelles Common to Plant and Animal Cells
- Cell Membrane
- Controls the entry and exit of substances.
- Cytoplasm
- Jelly-like substance that holds organelles; site of many cellular reactions.
- Nucleus
- Controls cell activities and holds the cell's DNA.
- Nucleolus
- Responsible for making ribosomes.
- Ribosomes
- Sites of protein synthesis (make proteins).
- Mitochondria
- Generates ATP (energy) through cellular respiration.
- Rough Endoplasmic Reticulum (Rough ER)
- Transports proteins.
- Smooth Endoplasmic Reticulum (Smooth ER)
- Synthesizes fats and lipids.
- Golgi Apparatus
- Packages and ships proteins and lipids.
- Vesicles
- Small sacs that transport materials within the cell.
- Vacuoles
- Storage for water and waste (typically small in animal cells).
- Lysosomes
- Contain enzymes to digest waste and cellular debris (more common in animal cells).
Organelles Unique to Plant Cells
- Cell Wall
- Provides structural support and protection.
- Chloroplasts
- Site of photosynthesis.
- Large Central Vacuole
- Stores water and helps maintain turgor pressure.
Organelles Unique to Animal Cells
- Centrioles: Assist in cell division.
- Higher quantity of lysosomes.
Cell Labeling Requirements
Key structures required for labeling diagrams:
Animal Cell Labels
- Membrane, Cytoplasm, Nucleus, Nucleolus, Ribosomes, Mitochondria, ER (Smooth/Rough), Golgi Apparatus, Small Vacuoles, Lysosomes, Centrioles.
Plant Cell Labels
- All structures listed for animal cells, plus: Cell Wall, Chloroplasts, and Large Central Vacuole.
Reasons for Cell Division
- Growth
- Repair of damaged tissue
- Reproduction (Asexual or Sexual)
Types of Cellular Reproduction
- Asexual Reproduction
- Involves one parent, producing genetically identical offspring (e.g., mitosis, budding, binary fission).
- Sexual Reproduction
- Involves two parents, resulting in genetically unique offspring.
Osmosis Versus Diffusion
- Diffusion
- The movement of particles from an area of high concentration to an area of low concentration.
- Osmosis
- The movement of water across a semipermeable membrane toward the area of higher solute concentration.
The Cell Cycle Stages
- Interphase
- The cell grows, DNA replicates, and the cell prepares for division.
- Mitosis
- The nucleus divides (Prophase, Metaphase, Anaphase, Telophase).
- Cytokinesis
- The cytoplasm splits, resulting in two identical daughter cells.
Mitosis Phases (PMAT)
- Prophase: Chromosomes condense, the nucleus disappears, and the spindle fibers begin to form.
- Metaphase: Chromosomes align along the center (metaphase plate) of the cell.
- Anaphase: Chromatids pull apart and move toward opposite poles.
- Telophase: New nuclei reform around the separated chromosomes, and the chromosomes unwind.
Cancer Biology
- Definition
- Uncontrolled and abnormal cell division.
- Causes
- Exposure to carcinogens (e.g., UV radiation, smoking, chemicals), genetic predisposition, and certain viruses.
- Tumors
- Benign: Non-cancerous, localized growth.
- Malignant: Cancerous, capable of invasion.