Monera, Protozoa, Algae, Fungi & Plant Nutrients: A Comprehensive Look

Posted on Mar 4, 2025 in Biology

Monera: Microscopic Prokaryotes

Monera are microscopic, unicellular prokaryotes that reproduce asexually.

Eubacteria: Photosynthetic and Chemotrophic

Photosynthetic:

  1. Cyanobacteria with chlorophyll.
  2. Other bacteria with bacteriochlorophyll; photosynthesis without O2.

Chemotrophy: No light or O2 energy.

Heterotrophic Oxidation: Obtain nutrients from other sources, mostly saprophytic (fermentation), parasites, and symbionts causing diseases.

Archaebacteria

  • Methanogens: Thrive in anaerobic, methane-rich environments.
  • Extreme Halophiles: Live in high-salt concentrations.
  • Thermoacidophiles: Found in acidic hot springs.

Protozoa: Heterotrophic Organisms

Protozoa are heterotrophs.

Types of Protozoa

  • Flagellates: Possess one or more flagella used for movement (e.g., Trypanosoma gambiense, causing sleeping sickness).
  • Ciliates: Mostly free-living, have a cytostome (mouth) in the plasma membrane, two nuclei (macro and micro), and cilia for movement (e.g., Paramecium).
  • Rhizopods: Move using pseudopods, also used to capture food (e.g., Amoebae).
  • Sporozoa: Parasites without locomotor organs (e.g., Malaria).

Algae: Autotrophic Organisms

Microalgae

Microscopic autotrophs living in water.

  • Euglenophytes: Unicellular with flagella, lacking a cell wall.
  • Diatoms: Have a silicic shell composed of two leaflets; fossils form diatomite.

Macroalgae

  • Green Algae: Found in seawater, contain chloroplasts (e.g., Ulva).
  • Brown Algae: Found in deeper waters; the pigment fucoxanthin allows them to thrive (e.g., Fucus and Kelp). Alginate, used as a gelling stabilizer, is extracted from them.
  • Red Algae: Found in the deepest waters; phycoerythrin enables photosynthesis at great depths (e.g., Gelidium, used to make agar).

Fungi: Decomposers and Parasites

Unicellular or multicellular organisms without true tissues. Tubular filaments called hyphae form a network called mycelium. Compacted hyphae form reproductive structures (carpophores or mushrooms). They feed by direct absorption from the medium.

Types of Fungi

  • Zygomycetes: Produce zygospores and have a coenocytic structure (e.g., parasites of fruits like black and white bread mold).
  • Ascomycetes: Micro and macro fungi such as yeasts, morels, and truffles (e.g., ergot).
  • Basidiomycetes: True mushrooms (e.g., rust of wheat, carbon from maize).
  • Deuteromycetes: (e.g., Aspergillus, Penicillium) have fermentative properties and can cause diseases.

Lichens (Micoficofitos)

Symbiotic association between an ascomycete fungus and cyanobacteria. The photosynthetic symbiont (phycobiont) provides nutrients, and the fungus (micobiont) provides minerals, water, and salts. Asexual reproduction occurs through fragmentation, and sexual reproduction occurs only with asci in apothecia. They can be fructilose, foliose, or crustose.

Plant Nutrients: Absorption and Transport

Nutrients

  • Salts: Absorbed through simple diffusion (osmosis), facilitated diffusion (using transport molecules), and active transport (energy consumption) by protein transporters (pumps).
  • Water: Absorbed through osmosis.

Saline soil concentration affects water absorption.

Water passes through root hairs via simple diffusion. Influencing factors:

  • Soil Water Content: More water leads to more absorption.
  • Solute Concentration in Soil: More salts decrease absorption.
  • Temperature: Higher temperature increases absorption.
  • Aeration: More aeration promotes root development and absorption.

Gases

Plants respire, consuming O2 and expelling CO2. In photosynthesis, the process is reversed. Gas exchange occurs through stomata via simple diffusion.

Transpiration

Water loss through stomata. Factors influencing transpiration:

  • Relative Humidity: Higher humidity causes stomata to open less.
  • Wind Speed: Higher wind speed increases transpiration.
  • Temperature: Higher temperature increases transpiration.

Crude Sap Transport

Water and mineral salts are transported through the xylem via capillarity. The liquid adheres to the walls of narrow tubes and ascends.