Lecture on Cell Components and Organelles

Overview

• Focus on Unit 4, Chapter 3, Part C: Cytoplasm and Organelles
• Cytoplasm: Area between plasma membrane and nucleus
  • Contains cytosol (aqueous solution), inclusions, and organelles
• Importance of organelles as metabolic machinery

Cytoplasmic Organelles

Membranous Organelles

• Mitochondria

  • Known as the "powerhouse" of the cell
  • Produces ATP through aerobic cellular respiration
  • Double membrane with inner folds called cristae
  • Contains its own DNA and ribosomes
  • Can divide independently through fission

• Endoplasmic Reticulum (ER)

  • Rough ER: Studded with ribosomes, site of protein synthesis
  • Smooth ER: Lipid metabolism, detoxification, calcium storage

• Golgi Apparatus

  • Modifies, sorts, and packages proteins and lipids from the ER
  • Consists of stacked membranous sacs
  • Directs products to various cell destinations through vesicles

• Peroxisomes

  • Contain enzymes for detoxifying harmful substances
  • Involved in the breakdown of fatty acids

• Lysosomes

  • Digestive compartments for ingested substances and cellular debris
  • Involved in autolysis and metabolic functions

Non-Membranous Organelles

• Ribosomes

  • Sites of protein synthesis
  • Free ribosomes: Make proteins for the cytosol
  • Membrane-bound ribosomes: Make proteins for membranes or secretion

• Cytoskeleton

  • Structural framework of the cell
  • Includes microfilaments (actin), intermediate filaments, and microtubules

• Centrioles

  • Involved in cell division and forming the basis of cilia and flagella

Cellular Extensions

• Cilia and Flagella

  • Cilia: Move substances across cell surfaces
  • Flagella: Propel entire cells (e.g., sperm)

• Microvilli

  • Increase surface area for absorption

The Nucleus

• Largest organelle, "control center" of the cell
• Contains DNA and nucleolus
• Nuclear Envelope: Double membrane with pores
• Nucleolus: Synthesis of ribosomal RNA
• Chromatin: DNA-protein complex, condenses into chromosomes during cell division

Additional Concepts

• Endomembrane System
  • Includes ER, Golgi apparatus, vesicles, and lysosomes
  • Coordinates production, degradation, and transport of molecules

Fascinating Details

• Mitochondria have their own DNA, tracing maternal lineage
• Animal cells' flexibility allows for diversity in cell types, unlike plant cells

Visual Aids and Figures

• Figures and diagrams illustrating organelles and processes

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These notes outline the major components and functions of organelles within the cell, as covered in today's lecture. This content is crucial for understanding cellular processes and will be tested in the upcoming exam.