A Level Biology Practice Exam

An organelle can be defined as what?

1. A rigid structure outside the plasma membrane

2. A cytoplasmic component that provides energy

3. A membrane-bound compartment with varying functions inside eukaryotic cells

4. A component found only in prokaryotic cells

The correct answer is: A membrane-bound compartment with varying functions inside eukaryotic cells

An organelle is best defined as a membrane-bound compartment with varying functions inside eukaryotic cells. This definition captures the essence of what organelles are and their role within eukaryotic cells, which are characterized by a complex internal structure. Organelles perform distinct functions that are crucial for the cell's life, including energy production, protein synthesis, waste processing, and cellular communication, among others. The presence of membranes around organelles such as the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus is a defining feature that distinguishes eukaryotic cells from prokaryotic cells, which lack these specialized compartments. Each organelle is uniquely adapted to its function, contributing to the overall efficiency and organization of the cell. By having different organelles that compartmentalize various biochemical processes, eukaryotic cells can carry out multiple functions simultaneously, thus facilitating complex life processes.