Biology: Microscopes and Bacteria

Microscopes

• The coarse adjustment knob is used for initial focus.
• The fine adjustment knob is used for precise focusing, especially on high power.
• The objectives are the lenses that magnify the specimen.
• The eyepiece is where you look through to view the magnified specimen.
• The stage is where the microscope slide is placed.

Prokaryotes

• Prokaryotes lack a nucleus and membrane-bound organelles.
• They were originally classified under the Kingdom Monera, and are sometimes still referred to as Monarans.
• Bacteria are classified into two kingdoms: Eubacteria and Archaebacteria.
• Bacteria are prokaryotes.

Bacteria

• Thermoacidophilic bacteria thrive in environments with high temperatures and acidity.
• Extreme halophiles prefer habitats with salinity levels 10 times higher than seawater.
• Chemosynthesizers convert inorganic compounds like H₂S and NH₃ into energy.

Classifying Bacteria

• Bacteria can be classified by their shape (coccus, bacillus, spirillum), motility (flagella, cilia, non-motile), metabolism (aerobic, anaerobic), respiration (chemoautotrophic, photoautotrophic), cell wall composition (Gram-positive, Gram-negative), and colony appearance.

Bacterial Diseases

• Bacteria cause a variety of diseases, including tetanus, tuberculosis, botulism, strep throat, staph infections, meningitis, typhoid fever, diphtheria, anthrax, MRSA (methicillin-resistant Staphylococcus aureus), pneumonia, and bubonic plague.

Treating Bacterial vs. Viral Infections

• Antibiotics are effective against bacterial infections, while vaccines prevent viral infections.

Bacterial Cell Wall Composition

• Gram staining is a method used to determine the composition of bacterial cell walls.
• Gram-positive bacteria have an additional layer of lipids in their cell membranes.

Bacterial Reproduction

• Bacteria reproduce through binary fission (asexual), in which a single cell splits into two identical cells.
• Sexual reproduction in bacteria occurs through conjugation, where genetic material is exchanged between two cells.
• Transduction involves a virus transporting bacterial DNA from one cell to another.
• Transformation occurs when living bacteria take up DNA from dead bacteria.

Protists

• Protists are classified into three categories: animal-like, plant-like, and fungi-like.

Animal-like Protists

• Also known as protozoans, are heterotrophs (cannot make their own food).
• Protozoans are further classified by their mode of movement:
  • Sarcodinians use pseudopods (false feet) for movement, like amoeba.
  • Zooflagellates move using flagella, like Triconympha.
  • Ciliaphorans are covered in hair-like projections called cilia, like paramecium.
  • Sporozoans are non-motile and parasitic, forming spores, like Plasmodium.

Plant-like Protists

• Plant-like protists are autotrophs (can make their own food) and include:
  • Red algae, also known as rhodophytes, are able to live in deep waters because their pigments allow them to harvest light.
  • Brown algae, like kelp, are large and multicellular.
  • Green algae, like Spirogyra (colonial) and Volvox, Chlamydomonas & Ulua (unicellular), contain chlorophyll and resemble land plants.
  • Euglena are unique in possessing two flagella, lacking a cell wall, and exhibiting both autotrophic and heterotrophic capabilities.

Red Tide

• Red tides are caused by blooms of dinoflagellates (a type of phytoplankton), which produce toxins that can harm marine life.

Phytoplankton

• Phytoplankton are plankton that produce their own food through photosynthesis.

Fungi-like Protists

• Fungi-like protists are not true fungi because they lack chitin in their cell walls. They include:
  • Plasmodial slime molds have a feeding stage known as the plasmodium.
  • Slime molds are mobile and decompose organic matter.
  • Water molds are responsible for causing diseases in plants, such as the Irish Potato Famine.

True Fungi

• Fungi belong to the Kingdom Fungi and are eukaryotes, meaning they have a nucleus and other membrane-bound organelles.
• True fungi have chitin in their cell walls.
• Examples of true fungi include:
  • Yeast (unicellular)
  • Shelf fungus (club fungi)
  • Puff balls (sac fungi)

Fungi Structure

• Fungi are made up of thin filaments called hyphae.
• Mushrooms are a type of club fungi.

Symbiosis

• Symbiosis is a relationship in which both partners benefit.
• Examples of symbiotic relationships involving bacteria:
  • Bacteria in our intestines help break down food.
  • Nitrogen-fixing bacteria in the soil help plants obtain nitrogen.
• A symbiotic relationship between protists and insects involves the bacteria within the protists that help termites digest wood.
• Lichen is a symbiotic relationship between algae and fungi.

Microscopes

• The coarse adjustment knob is used for initial focus.
• The fine adjustment knob is used for precise focusing, especially on high power.
• The objectives are the lenses that magnify the specimen on the stage.
• The eyepiece is where you look through to see the magnified specimen.

Prokaryotes

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

Bacteria

• Classified into the kingdoms Eubacteria and Archaebacteria.
• Some bacteria live in harsh environments like extreme temperatures and salinity.

Thermoacidophilic Bacteria

• Thrive in high temperatures and acidic environments.

Extreme Halophiles

• Prefer environments with salt concentrations 10 times higher than seawater.

Chemosynthesizers

• Bacteria convert inorganic compounds like hydrogen sulfide and ammonia into energy.

Bacteria Classification

• Can be classified based on shape, motility, metabolism, respiration, cell wall composition, and colony appearance.

Bacterial Diseases

• Some common bacterial diseases include tetanus, tuberculosis, botulism, strep throat, staph infections, meningitis, typhoid fever, diphtheria, anthrax, MRSA, pneumonia, and bubonic plague.

Treatment of Bacterial and Viral Infections

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

Bacterial Shapes

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

Antibiotic Resistance

• Occurs when bacteria evolve to become immune to antibiotics.

Causes of Antibiotic Resistance

• Overuse and misuse of antibiotics contribute to antibiotic resistance.

Bacterial Reproduction

• Asexual Reproduction (Binary Fission): One cell divides into two identical cells.
• Sexual Reproduction (Conjugation): Exchange of genetic material between two bacterial cells.
• Transduction: A virus carries bacterial DNA from one cell to another.
• Transformation: Living bacteria absorb DNA from dead bacteria.

Bacterial Cell Wall Composition

• Determined by Gram staining.

Gram-Positive Bacteria

• Have an extra layer of lipids in their cell membranes.

Protists

• Divided into three categories: animal-like, plant-like, and fungus-like.

Animal-like Protists (Protozoans)

• Heterotrophs.
• Classified based on their mode of movement.

Protozoan Movement

• Sarcodinians: Move using pseudopods (false feet), e.g., Amoeba.
• Zooflagellates: Use flagella for movement, e.g., Triconympha.
• Ciliaphorans: Covered in hair-like cilia for movement, e.g., Paramecium.
• Sporozoans: Non-motile spore-forming parasites, e.g., Plasmodium.

Plant-like Protists

• Include red, brown, and green algae.

Red Algae

• Contain pigments that allow them to thrive in deep water.

Colonial Green Algae

• Spirogyra is a notable example of a colonial green algae.

Brown Algae

• Kelp is an example of brown algae.

Euglena

• Possess two flagella, lack a cell wall, and can be both autotrophic and heterotrophic.

Unicellular Algae

• Volvox, Chlamydomonas, and Ulua are examples of unicellular algae.

Red Tide

• A phenomenon caused by blooms of dinoflagellates, which release toxins and turn the water red.

Phytoplankton

• Plankton that carry out photosynthesis.

Fungus-like Protists

• Include Plasmodial slime molds, slime molds, and water molds.

Fungi-like Protists Classification

• Not true fungi because they lack chitin in their cell walls.

Plasmodial Slime Molds

• The feeding stage is known as the plasmodium.

Water Molds

• Responsible for the Irish Potato Famine.

True Fungi

• Belong to the Kingdom Fungi.
• Contain chitin in their cell walls.

Unicellular Fungi

• Yeast is an example of a unicellular fungus.

Club Fungi

• Shelf fungus is an example of a club fungus.

Fungi Reproduction

• Fungi reproduce through spores.

Fungi and Symbiosis

• Fungi often engage in symbiotic relationships.

Symbiosis

• A relationship where both partners benefit.

Symbiotic Relationships Involving Bacteria

• Bacteria in our intestines help digest food.
• Nitrogen-fixing bacteria help plants obtain nitrogen.

Symbiotic Relationships Involving Protists

• Protozoa in termite intestines help break down wood.

Symbiotic Relationships Involving Algae and Fungi

• Algae and fungi form lichens.

Test your knowledge on the fundamental concepts of microscopes and the classification of prokaryotes. This quiz covers the parts of a microscope, characteristics of bacteria, and how types of bacteria are classified. Perfect for biology students seeking to understand these essential topics.