Biology: Microscopes and Prokaryotes

Microscopes

• Coarse Adjustment: Used for initial focus, the larger knob.
• Fine Adjustment: Used for precise focusing, the smaller knob.
• Objectives: Lenses that magnify the specimen, they are rotated to select different magnifications.
• Eyepiece: Lens you look through to view the magnified specimen.
• Stage: Platform where the microscope slide is placed.

Prokaryotes

• Lack a nucleus and membrane-bound organelles.
• Bacteria are classified as prokaryotes.

Bacteria

• Formerly classified in the Kingdom Monera (still sometimes referred to as Monarans).
• Currently classified into kingdoms Eubacteria and Archaebacteria.
• Can survive in harsh environments.

Thermoacidophilic Bacteria

• Thrive in extremely hot and acidic conditions.

Extreme Halophiles

• Favor environments with salt concentrations ten times higher than seawater.

Chemosynthesizers

• Convert inorganic compounds like hydrogen sulfide (H₂S) and ammonia (NH₃) into energy.

Bacteria Classification

• Shape (e.g., coccus, bacillus, spirillum).
• Motility (e.g., flagella, cilia).
• Metabolism (e.g., chemosynthesis, photosynthesis).
• Respiration (e.g., aerobic, anaerobic).
• Cell wall composition (e.g., Gram-positive, Gram-negative).
• Appearance of a Colony.

Bacterial Diseases

• Tetanus
• Tuberculosis (TB)
• Botulism
• Strep Throat
• Staph Infection
• Meningitis
• Typhoid Fever
• Diptheria
• Anthrax
• MRSA (Methicillin-resistant Staphylococcus aureus)
• Pneumonia
• Bubonic Plague

Bacterial vs. Viral Infections

• Antibiotics are effective against bacterial infections.
• Vaccines prevent viral infections.

Bacterial Shapes

• Coccus: Spherical or round-shaped.
• Bacillus: Rod-shaped.
• Spirillum: Spiral-shaped.

Antibiotic Resistance

• Occurs when bacteria become immune to antibiotics.

Causes of Antibiotic Resistance

• Overuse and misuse of antibiotics.

Bacterial Reproduction

• Asexual Reproduction – Binary Fission: One cell divides into two identical daughter cells.
• Sexual Reproduction – Conjugation: Exchange of genetic material between two bacteria cells.
• Transduction: A virus transfers bacterial DNA from one bacterium to another.
• Transformation: Living bacteria take up DNA from dead bacteria.

Bacterial Cell Wall Composition

• Determined by Gram Staining.

Gram-Positive Bacteria

• Possess an extra layer of lipids in their cell membrane.

Protist Categories

• Animal-like Protists (Protozoans): Heterotrophs. Classified by their method of movement.
• Plant-like Protists (Algae): Autotrophs. Known for their photosynthetic pigments.
• Fungus-like Protists: Heterotrophs. Decomposers with similarities to fungi.

Protozoan Classifications

• Sarcodinians: Move using pseudopods (e.g., amoeba).
• Zooflagellates: Move using flagella (e.g., Triconympha).
• Ciliaphorans (Ciliates): Covered in hair-like projections called cilia (e.g., Paramecium).
• Sporozoans: Non-motile, spore-forming parasites (e.g., Plasmodium).

Plant-like Protist Types

• Red Algae: Contain pigments that allow them to live in deep ocean depths.
• Brown Algae: Large, multicellular algae (e.g., kelp).
• Green Algae: Unicellular and colonial forms (e.g., Spirogyra).

Euglena

• Possess two flagella, no cell wall, and can be both autotrophic and heterotrophic.
• Can photosynthesize like plants and consume food like animals.

Unicellular Algae

• Volvox: Colonial green algae.
• Chlamydomonas and Ulua: Unicellular green algae.

Red Tide

• Blooms of dinoflagellates that produce toxins, turning the water red.

Phytoplankton

• Plankton that carry out photosynthesis.

Fungus-like Protists

• Plasmodial Slime Molds: Have a feeding stage known as "plasmodium."
• Slime Molds.
• Water Molds: Caused the Irish Potato Famine.

True Fungi

• Belong to the Kingdom Fungi.
• Have chitin in their cell walls.
• Yeast is a unicellular fungus.
• Shelf Fungi are an example of club fungi.

Symbiosis

• A relationship where both partners benefit.

Examples of Symbiotic Relationships

• Bacteria and Animals: Bacteria in our intestines aid in food digestion.
• Bacteria and Plants: Nitrogen-fixing bacteria in the soil provide nitrogen to plants.
• Protists and Insects: Termites rely on protists with bacteria to break down wood.
• Algae and Fungus (Lichens): Algae provides food through photosynthesis, while the fungus provides structure and protection.

Identifying Protists

• Amoeba: Sarcodine with pseudopods.
• Diatoms: Geometric-shaped algae.
• Paramecium: Ciliate with cilia.
• Euglena: Green, flagellated protist.