Biochemical composition: most microbial cellular structures and enzymes are primarily composed of what kind of macromolecule?

Introduction / Context:
Cells are built from macromolecules with distinct roles. Understanding which macromolecule predominates in structural components and enzymes helps explain cell function, metabolism, and targets for antimicrobial drugs.

Given Data / Assumptions:

• Options include lipids, proteins, carbohydrates, or combinations.
• We consider typical microbial cells such as bacteria and fungi.

Concept / Approach:
Enzymes are by definition proteins (with rare catalytic RNAs called ribozymes as exceptions). Many structural components inside cells, such as cytoskeletal elements and transporters, are proteins. While membranes are rich in lipids and cell walls may contain carbohydrates like peptidoglycan or polysaccharides, the bulk of intracellular structures and essentially all enzymes are proteinaceous.

Step-by-Step Solution:

Verification / Alternative check:
Biochemistry textbooks define enzymes as proteins (except RNA enzymes), and proteomics shows the central role of proteins in microbial physiology.

Why Other Options Are Wrong:

• A: Lipids form membranes and energy stores but are not the main enzyme class.
• C: Carbohydrates provide energy and structural polymers but are not enzymes.
• D: Combination answer still does not capture that enzymes are proteins.

Common Pitfalls:
Equating cell wall mass with overall cell composition; intracellular protein content and enzymatic functions dominate metabolic activity.

Final Answer:
proteins