Core physiology of fungi: Which statement correctly describes a defining nutritional strategy of true fungi (kingdom Fungi) relevant to medical and environmental microbiology?

Introduction / Context:
Fungi play critical roles as decomposers, pathogens, and industrial workhorses. Distinguishing fungal cell biology from that of plants and bacteria is essential for understanding diagnostics, drug targets, and ecological functions.

Given Data / Assumptions:

• We contrast fungal traits with plants (photosynthesis) and bacteria (prokaryotes with peptidoglycan walls).
• We focus on nutrition and cell structure basics applied across major fungal groups (molds, yeasts, mushrooms).

Concept / Approach:
Fungi are heterotrophs. They secrete hydrolytic enzymes into their environment to depolymerize complex substrates (cellulose, lignin, keratin), then absorb the resulting soluble nutrients. They are eukaryotic (true nucleus, organelles) and possess cell walls primarily composed of chitin and glucans, not peptidoglycan. They also lack chlorophyll and do not perform photosynthesis.

Step-by-Step Solution:
Eliminate photosynthesis: fungi lack chloroplasts and chlorophyll. Eliminate prokaryotic status: fungi are eukaryotes. Eliminate peptidoglycan: fungal walls contain chitin/glucans. Identify hallmark feeding: extracellular digestion via secreted enzymes, then absorption.

Verification / Alternative check:
Microscopy shows nuclei and organelles; chemical assays detect chitin; genomic data confirm eukaryotic lineage and enzyme repertoires for extracellular digestion.

Why Other Options Are Wrong:

• Photosynthetic: incorrect—fungi are chemoheterotrophs.
• Prokaryotic: incorrect—fungi are eukaryotic.
• Peptidoglycan walls: incorrect—unique to bacteria.

Common Pitfalls:
Confusing fungi with plants due to cell walls; composition and nutrition differ markedly.

Final Answer:
secrete extracellular enzymes to breakdown nutrients