cell types

Introduction to Cell Types

• Three domains of life:

  • Eukaryotic Cells

  • Prokaryotic Cells (contains Bacteria and Archaea)

  • Understanding differences is critical for microbiology and health-related studies.

Cell Wall Presence

• Eukaryotes:

  • Single-celled eukaryotes typically lack cell walls.

  • Animals lack cell walls entirely.

  • Fungi have cell walls (made of chitin).

  • Algae also possess cell walls.

• Prokaryotes usually have cell walls composed primarily of peptidoglycan.

Importance of Bacterial Studies

• Understanding interactions with drugs and other microorganisms:

  • Relevance in health fields, such as responses to treatments.

• Utilize animal testing to predict effects on human cells due to structural similarities.

• Practical benefits: Food sources (mushrooms, yeast) and antibiotics (e.g., penicillin from molds).

Classification of Organisms

• Organisms classified based on sexual reproduction methods and structures.

• Cell walls (Fungi: chitin, Plants: glycoproteins and polysaccharides).

Eukaryotic Cell Structure

• General Characteristics:

  • More complex than prokaryotic cells.

  • Motility present in most eukaryotic cells since they possess structures for movement (flagella, cilia).

• Key Organelles and Structures:

  • Nucleus: Contains linear chromosomes, encased in a double membrane with nuclear pores (allowing passage in and out).

  • Ribosomes: Significant for protein synthesis; eukaryotes possess 80S ribosomes, while prokaryotes have 70S ribosomes.

  • Endoplasmic Reticulum: Rough (with ribosomes) for protein synthesis; Smooth (without ribosomes) for lipid synthesis and processing.

  • Golgi Apparatus: Modifies, sorts, and packages proteins for secretion or use within the cell.

  • Mitochondria: Energy production (ATP) through cellular respiration; has its own circular DNA.

Comparison of Prokaryotic and Eukaryotic Cells

• Membrane Composition:

  • Both types have a plasma membrane, but eukaryotes have internal bound membranes and a more complex structure.

• Genetic Material:

  • Eukaryotic cells contain a true nucleus; prokaryotic genetic material is located in the nucleoid region.

• Structural Complexity:

  • Eukaryotes have membrane-bound organelles with distinct functions; prokaryotes are simpler and lack compartmentalization.

Locomotion in Cells

• Prokaryotic Movement: Typically through flagella that rotate.

• Eukaryotic Locomotion:

  • Flagella and cilia, where cilia can coordinate for movement.

  • Eukaryotic flagella wave back and forth.

Role of Cell Structures

• Cytoskeleton: Maintains cell shape, enables motility, and transports materials.

• Cell Wall Differences:

  • Important for identifying bacteria (gram-positive vs. gram-negative). Penicillin targets peptidoglycan in bacterial cell walls.

Clinical Relevance

• Understanding cell structures aids in diagnosing and treating infections, identifying tissue necrosis, and informing treatment choices.

• Laboratory relevance: Tests for infection, efficacy of antibiotics, and studying structural responses to injuries.

Summary

• Knowledge of prokaryotic and eukaryotic structures is critical for clinical applications, understanding human biology, and developing health-related interventions.