UAA 18: Microorganisms

UAA 18: Microorganisms – Characteristics and Diversity

Overview and Classification

Microorganisms are highly diverse, microscopic living organisms, predominantly unicellular, found universally. This group encompasses bacteria, protozoa, viruses, prions, algae, and microscopic fungi.

Structural and Functional Attributes

• Most have a membrane and cytoplasm.

• Some possess a nucleus (e.g., protists, microscopic fungi), with certain protists capable of photosynthesis.

• Others lack a nucleus but have complex structures (e.g., bacteria).

• Viruses are the simplest, comprising a genetic material capsule without a nucleus.

• Photosynthesis occurs in various microorganisms, not just plants.

Size Comparison

Microorganism sizes vary significantly:

• Viruses: ~0.01 µm (smallest).

• Bacteria: ~1 µm.

• Microscopic Fungi: ~10 µm.

• Protozoa: ~10 to 100 µm (largest).

For comparison, animal cells are around 10 µm, and plant cells are generally larger (~100 µm).