GED Science TestLife ScienceEasy
A student is observing plant cells under a microscope. They notice a rigid outer layer that provides structural support and protection to the cell, located external to the plasma membrane. Which of the following organelles or structures is the student observing?
- AVacuole
- BChloroplast
- CMitochondrion
- DCell wall
Show answer & explanationAnswer & explanation
Correct answer: D. Cell wall
The cell wall is a rigid outer layer found in plant cells, fungi, algae, and bacteria. Its primary function is to provide structural support, protection, and regulate cell volume, located outside the plasma membrane.
Why the other options are wrong
- A. Vacuoles are large, membrane-bound sacs within the cell, primarily for storage and maintaining turgor pressure, not an outer layer.
- B. Chloroplasts are internal organelles responsible for photosynthesis.
- C. Mitochondria are responsible for cellular respiration and are internal organelles.
Plant Cell Wall
A rigid layer found outside the plasma membrane of plant cells, providing structural support, protection, and acting as a filtering mechanism.
- Composed mainly of cellulose in plants.
- Prevents excessive water uptake.
- Distinguishes plant cells from animal cells.
Memory trick: Plant Cell's Core: Cell wall, Chloroplasts, Vacuole, Nucleus.