Identifying Plant Cell Structures via Electron Microscopy

Steps:

• Examine outer layer: Thick, rigid structure indicates cell wall, not flexible membrane.
• Identify central compartment: Large, fluid-filled area is the vacuole, occupying most cell volume.
• Locate organelle with internal membranes: Stacked thylakoids confirm chloroplast for photosynthesis.
• Check nuclear region: Dense spherical body within nucleus is the nucleolus, site of ribosome synthesis.

Why D is correct:

• Matches plant cell definitions: Cell wall provides rigidity (unique to plants), vacuole stores water, chloroplast enables photosynthesis, nucleolus assembles ribosomes.

Why the others are wrong:

• A: Misidentifies P as membrane (plants have cell wall) and R as mitochondrion (lacks thylakoids).
• B: Misidentifies P as membrane (ignores cell wall) despite correct R and S.
• C: Misidentifies S as nucleus (label shows internal nucleolus, not whole nucleus).

Final answer: D