Fungi are heterotrophic . Saprophytic fungi grow on dead organic matter. Parasitic fungi grow on living tissues. Yeasts are unicellular organisms that multiply by a process of budding A small swelling develops on the mother cell, and this develops to full size. The mother and daughter cell then split to form two independent cells.
Moulds produce a mat of thread-like structures known as hyphae or mycelia .
They also produce a staggering variety of spores . These may be produced asexually or sexually and are important in the identification of moulds. Protozoa Protozoa are unicellular eukaryotes . Many protozoa are free living, but others cause serious infections. Protozoa can infect any human tissue, and are the cause of a variety of diseases.