Prokaryotes and Protozoa

Overview of Prokaryotes and Protozoa

  • Discussion focused on examples of prokaryotes and a specific type of microorganisms known as protozoa.

Prokaryotes

  • Definition: Prokaryotes belong to the kingdom Prokaryota.

  • DNA Characteristics:

    • Contains DNA which consists of nucleotides.

    • DNA is circular in shape.

    • DNA is not contained within a nucleus; rather, it is located within a region called the nucleoid.

  • Additional Features:

    • Bacteria may be flagellated or non-flagellated.

    • Flagellum: A long extension for movement, crucial for motility in certain bacteria.

Bacterial Structure

  • Visual representation of a bacterium highlighting the following components:

    • Flagellum: Long extension used for movement.

    • Ribosomes: Structures responsible for protein synthesis.

    • Nucleoid: Region where DNA is located.

    • Pili (Hairs): Small extensions aiding in attachment and conjugation.

    • Cell Wall: Protective outer layer.

    • Capsule: Additional layer providing protection, not always visible in every diagram.

    • Plasma Membrane: Lipid bilayer surrounding the cell.

    • Cytoplasm: Gel-like substance inside the cell.

Shapes of Bacteria

  • Cocci: Round bacteria.

    • Singular: coccus; Plural: cocci.

    • Examples:

    • Streptococcus: Bacteria that form chains.

    • Staphylococcus: Bacteria that form clusters.

  • Bacillus: Rod-shaped bacteria.

    • Examples:

    • Diplobacillus: Bacteria in pairs.

    • Streptobacillus: Bacteria in chains.

  • Spirilla: Spiral-shaped bacteria.

Preparation for Lab Exam

  • Students should identify and differentiate between the given shapes and structures of bacteria.

Protozoa

  • Definition: Protozoa belong to the kingdom Protista and are very small microorganisms.

  • They have different modes of movement compared to bacteria.

Types of Protozoa

  1. Amoeba

    • Structures to highlight:

      • Nucleus: Contains genetic material.

      • Cell Membrane: Encloses the cell.

      • Food Vacuole: Digestive structure.

      • Contractile Vacuole: Regulates water balance.

      • Pseudopod: Means "false foot"; used for movement and feeding.

    • Movement: Amoeba moves by extending its pseudopodia, enabling locomotion and feeding.

  2. Paramecium

    • Structures to highlight:

      • Contractile Vacuole: Regulates water balance.

      • Food Vacuole: Digestive structure.

      • Cilia: Short hair-like extensions responsible for movement.

    • Movement Mechanism: Paramecium moves by the coordinated beating of its cilia.

    • Other Examples of Ciliates:

      • Didinium: A type of ciliate.

      • Verticella: Another type of ciliate.

    • Students must identify these examples alongside paramecium during the exam.

  3. Flagellates

    • Characterized by long hair-like structures called flagella used for movement.

    • Students do not need to memorize specific names for this group but should recognize flagella in sketches.

Conclusion

  • Important to review and understand the structures and movements of both prokaryotes and protozoa for the lab examination.

  • Thank you message for attendance and attention.