The organelle responsible for the transportation of substances within the cell is

Step 1: Analyze the question The question asks which organelle transports substances within the cell (intracellular transport), not into or out of it.

Step 2: Explain the concept The endoplasmic reticulum (ER) is a network of interconnected membrane-bound channels and sacs running through the cytoplasm. It acts like the cell's "transport highway":

• Rough ER (with ribosomes) makes proteins and moves them through its channels, often toward the Golgi apparatus.
• Smooth ER makes lipids and moves them around the cell.

Step 3: Check each option

• A. Cell membrane: Controls what enters and leaves the cell (transport across the cell boundary), not transport within the cell.
• B. Chloroplast: Site of photosynthesis in plant cells.
• C. Endoplasmic reticulum: Its channels carry substances from one part of the cell to another. ✔
• D. Lysosome: Contains digestive enzymes that break down worn-out organelles and foreign materials.
• E. Mitochondrion: Site of aerobic respiration, releasing energy (ATP).

Step 4: Answer The correct option is C. endoplasmic reticulum.

Tip: Remember "ER = Express Route." The ER is the cell's internal transport system. Also, watch for the key word "within" in questions like this. If the question said "into and out of the cell," the answer would be the cell membrane.