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:

    1. Mitochondria

    1. Peroxisome

    1. 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

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