Terminology in microbiology and botany – meaning of “achlorophyllous” In organism descriptions, the term “achlorophyllous” refers to what characteristic?

Introduction / Context:
Terminology precision is essential in taxonomy and physiology. The adjective “achlorophyllous” appears in descriptions of fungi, parasitic plants, and certain protists. Understanding the meaning prevents misinterpretation of an organism ability to perform photosynthesis and the ecological role it may play as a saprobe or parasite.

Given Data / Assumptions:

• The term contains the prefix “a-” which often means absence or without.
• Chlorophyll is the green photosynthetic pigment essential for light capture in oxygenic photosynthesis.
• Some eukaryotes lack chlorophyll and therefore rely on alternative nutrition such as heterotrophy.

Concept / Approach:
Achlorophyllous literally means “without chlorophyll.” Organisms with this description cannot photosynthesize using chlorophyll dependent systems. Many fungi are achlorophyllous and depend on external organic carbon. Some parasitic plants like Rafflesia are also achlorophyllous, tapping host vascular systems for carbon. The term does not automatically imply absence of chloroplasts in all cases, because some lineages may retain non photosynthetic plastids for other metabolic tasks. The definition focuses on pigment absence rather than broader cell biology details.

Step-by-Step Solution:
Break down the word: a- (without) + chlorophyllous (containing chlorophyll).Relate meaning to functional consequence: absence of normal chlorophyll based photosynthesis.Select “Lacking chlorophyll.”

Verification / Alternative check:
Standard glossaries in botany and microbiology provide the exact definition “achlorophyllous = without chlorophyll,” aligning with practical usage across many organism groups.

Why Other Options Are Wrong:

• Leading in chlorophyll: opposite of the actual meaning.
• Unable to use carbon dioxide: too specific and not always true; some heterotrophs still use CO2 in anaplerotic reactions.
• Having chloroplasts without pigments: not part of the definition and not universal.

Common Pitfalls:
Equating achlorophyllous with absence of all plastids. Some organisms have relic plastids even without chlorophyll. The term strictly refers to pigment absence.

Final Answer:
Lacking chlorophyll.