2101.114 Eukaryotic Cells 1 Lecture Slides

Eukaryotic Cells Overview

• Key Structures:

  • Nuclear envelope

  • Chromatin (DNA + proteins)

  • Nucleolus

  • Ribosomes

  • Microtubule

  • Centrioles

  • Intermediate Filaments

  • Microfilaments (Actin)

  • Peroxisome

  • Rough Endoplasmic Reticulum

  • Smooth Endoplasmic Reticulum

  • Plasma Membrane

  • Lysosome

  • Golgi Apparatus

  • Cytosol

  • Mitochondrion

  • Vacuole

Endomembrane System

• Components:

  • Membrane-bound organelles

  • Derivation from the outer membrane of the nucleus

  • Transport facilitated by transport vesicles

• Membrane-Bound Organelles:

  1. Nucleus

  2. Smooth Endoplasmic Reticulum

  3. Rough Endoplasmic Reticulum

  4. Golgi Apparatus

  5. Lysosomes

  6. Vacuoles

Other Membrane-Bound Organelles:

• 7. Mitochondria

• 8. Peroxisome

• 9. Chloroplast

Other Cell Structures

• Ribosome:

  • Small brown dots; sites for protein synthesis

• Cytoskeleton:

  • Provides structure and support with components such as microfilaments and microtubules

• Extracellular Structures:

  • Supportive structures surrounding the cell

Animal Cell Structure

• Flagellum:

  • Motility structure composed of microtubules

• Endoplasmic Reticulum (ER):

  • Network of membranous sacs; includes Rough and Smooth ER

• Nuclear Envelope:

  • Double membrane enclosing the nucleus; continuous with ER

• Nucleolus:

  • Involved in ribosome production

• Golgi Apparatus:

  • Active in synthesis, modification, sorting, and secretion of cell products

• Lysosome:

  • Digestive organelle for macromolecules

• Microvilli:

  • Projections to increase surface area

Plant Cell Structure

• Chloroplast:

  • Photosynthetic organelle converting sunlight to energy

• Cell Wall:

  • Maintains shape; protects from damage

• Central Vacuole:

  • Functions in storage and plant growth

Prokaryotic Cells

• Components Found in Prokaryotic Cells:

  • a. DNA

  • b. Ribosomes

  • d. Cell Membrane

  • e. Cytoplasm

Genetic Instructions in Eukaryotic Cells

• Nucleus:

  • Houses most DNA

  • Ribosomes synthesize proteins using DNA information

Nucleus Structure

• Nuclear Envelope:

  • Double membrane with nuclear pores

  • Maintains shape through nuclear lamina

• Chromatin:

  • DNA organized into chromosomes; condenses for cell division

• Nucleolus:

  • Site for rRNA synthesis

Ribosomes: The Protein Factories

• Function:

  • Sites of protein synthesis, found bound to ER or free in cytosol

• Protein Synthesis Locations:

  • Bound ribosomes: synthesize proteins for plasma membrane, endomembrane system, or secretion

  • Free ribosomes: synthesize all other proteins

Endomembrane System Functions

• Components:

  • Nuclear envelope

  • Endoplasmic reticulum

  • Golgi apparatus

  • Lysosomes

  • Vacuoles

  • Plasma membrane

• Functionality:

  • Transport of molecular materials via vesicles

Endoplasmic Reticulum (ER)

• Structure:

  • Continuous with nuclear envelope

  • Divided into Smooth ER (no ribosomes) and Rough ER (ribosome-studded)

• Functions:

  • Smooth ER: lipid synthesis, detoxification

  • Rough ER: protein synthesis due to ribosomes

Golgi Apparatus

• Structure:

  • Composed of flattened membranous sacs (cisternae)

• Functions:

  • Modifies, manufactures, sorts, and packages materials

Lysosomes: Digestive Organelles

• Functionality:

  • Membranous sac of hydrolytic enzymes for digestion

  • Enzymes function best in acidic conditions

• Processes:

  • Phagocytosis: engulfing of cells and subsequent digestion

  • Autophagy: recycling of cell’s own organelles

Vacuoles: Diverse Compartments

• Types of Vacuoles:

  • Food vacuoles from phagocytosis

  • Central vacuoles in plants for storage and turgor pressure maintenance

Relationships Among Organelles

• Functionality:

  • Lysosomes fuse for digestion

  • Golgi apparatus packages proteins for secretion

  • Endomembrane system provides transport and functional integration