Biology 2e - Chapter 4 Key Terms Notes

Introduction

This section provides key terms related to Chapter 4 of the Biology 2e textbook by OpenStax, focusing on cell structure and function, the endomembrane system, and cellular interactions.

Key Terms

Cell Theory

• Unified Cell Theory: States that all living organisms are composed of cells, which are the basic unit of life. New cells arise from pre-existing cells.

Cell Components

• Cell Wall: A rigid structure that provides protection and shape to plant cells.
• Central Vacuole: Large organelle in plant cells for storage, growth, and degradation of macromolecules.
• Centrosome: Organizing center for microtubules in animal cells, consists of two centrioles.

Photosynthesis

• Chlorophyll: Green pigment essential for capturing light energy in photosynthesis.
• Chloroplast: Organelle in plant cells where photosynthesis occurs.

Genetic Material and Cell Nucleus

• Chromatin: Complex of DNA and proteins forming chromosomes.
• Chromosome: Carries genetic information in the form of DNA.

Cell Surface Structures

• Cilium (plural = Cilia): Hair-like structures for cell movement or moving substances across the cell surface.
• Flagellum: Longer, whip-like structure used for cell movement.

Internal Cell Structures

• Cytoplasm: Gel-like substance between the plasma membrane and nucleus, containing organelles.
• Cytoskeleton: Network of protein fibers maintaining cell shape and enabling movement.

Organelles

• Endoplasmic Reticulum (ER): Membrane network involved in protein and lipid synthesis. Comprises:
  • Rough ER (RER): Studded with ribosomes, involved in protein modification.
  • Smooth ER (SER): Involves lipid synthesis and detoxification processes.
• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for transport.
• Lysosome: Contains enzymes for digestion of cellular waste.
• Mitochondria: Powerhouse of the cell, responsible for energy (ATP) production.
• Nucleus: Houses DNA and directs cell activities.
• Peroxisome: Breaks down fatty acids and detoxifies harmful compounds.

Membrane Structures

• Plasma Membrane: Phospholipid bilayer that forms the cell boundary, controlling entry and exit of substances.
• Plasmodesma (plural = Plasmodesmata): Channels between plant cells for material transport.

Cellular Junctions

• Desmosome: Connections between animal cells for mechanical stability.
• Gap Junction: Channels allowing communication between animal cells.
• Tight Junction: Creates a watertight seal between animal cells.

Microscopy

• Electron Microscope: Uses electrons to visualize small specimens.
• Light Microscope: Uses visible light for magnification of specimens.

Additional Information

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These key terms and concepts are foundational for understanding cellular biology and its applications. Familiarity with these terms will aid in grasping subsequent chapters on cellular processes and structures.