Reverse transcriptase is the enzyme that produces a cDNA copy of an RNA template. Return to text . Bacteria are prokaryotes because they lack a clearly defined nucleus and sub-cellular organelles. Return to text . Heterotrophs require complex organic chemicals in order to grow.
Autotrophs can grow using simple, inorganic chemicals.
Phototrophs use and require light as a source of energy and chemotrophs require a supply of chemical energy, but can grow in the dark. Humans and many microbes are heterotrophs and chemotrophs whilst plants are autotrophs and phototrophs. Return to text . A saprophyte is an organism that derives its nutrients from dead tissues. Return to text .