A microscopic unicellular organism isolated from a freshwater pond exhibits mixotrophic nutrition: it photosynthesizes in sunlight using chloroplasts, but absorbs organic nutrients heterotrophically when kept in the dark. It moves by means of a single flagellum and lacks a cellulose cell wall, possessing a flexible proteinaceous pellicle beneath its plasma membrane instead. Which of the following protists is described, and what is its primary carbohydrate storage product?
- Euglena, which stores carbohydrate as paramylonAnswer
- BChlamydomonas, which stores carbohydrate as starch
- CAmoeba, which stores carbohydrate as glycogen
- DParamecium, which stores carbohydrate as cellulose
Answer
Euglena, which stores carbohydrate as paramylon
The correct answer identifies Euglena, which uniquely combines animal-like features (locomotion by a single flagellum, absence of a cellulose cell wall, presence of a flexible pellicle) and plant-like features (chloroplasts for autotrophic nutrition). When photosynthetic product is accumulated, it is stored as paramylon rather than typical plant starch.
Step-by-Step Solution
Key Concept
Distinctive structural, nutritional, and biochemical features of Euglena
Estimated Time:1m 30s