Reverse transcriptase is used to make cDNA from an RNA template.

A. Conjugation: Conjugation involves direct physical contact (often via a sex pilus) to transfer genetic material from donor to recipient.

B. Transformation: Transformation involves uptake of free DNA from the environment and does not require donor–recipient contact.

C. Transduction: Transduction transfers DNA between bacteria via bacteriophages and does not require direct cell-to-cell contact.

D. Binary fission: Binary fission is the asexual reproduction of a single cell into two daughter cells and does not involve genetic transfer between separate donor and recipient cells.

A. Apoenzymes: Apoenzymes are the protein portion of an enzyme that require a cofactor to become active; this term describes part of an enzyme rather than its cellular location or whether it functions inside the cell.

B. Exoenzymes: Exoenzymes are secreted outside the cell to act on extracellular substrates; this term indicates extracellular action rather than intracellular function.

C. Constitutive enzymes: Constitutive enzymes are produced continuously at a fairly constant rate regardless of substrate presence; this describes regulation, not specifically intracellular location.

D. Regulated enzymes: Regulated enzymes change their level or activity in response to environmental conditions or signals; this term refers to control mechanisms rather than being intrinsically intracellular.

E. Endoenzymes: Endoenzymes function within the cell (intracellular enzymes) to catalyze metabolic reactions inside the cytoplasm or organelles.