Which of the following describes a lysosome?
A. A double-membrane organelle that generates energy for the cell
B. A complex network of membranes that participate in protein synthesis
C. A nonmembranous organelle that is responsible for protein synthesis
D. A single-membrane vesicle with powerful digestive enzymes
E. A small single-membrane vesicle used by the cell for food transportation
The correct answer and explanation is:
The correct answer is D. A single-membrane vesicle with powerful digestive enzymes.
Lysosomes are membrane-bound organelles found in animal cells. They are essentially small, spherical vesicles that contain enzymes capable of breaking down various biological molecules. These digestive enzymes are known as hydrolytic enzymes, and they can break down proteins, lipids, nucleic acids, and carbohydrates, which is critical for the cell’s ability to digest nutrients and recycle cellular components.
Lysosomes play an important role in cellular digestion, which involves the breakdown of large molecules into smaller, more manageable parts. This process is essential for the cell’s metabolic processes and for the removal of waste material. For example, when a cell engulfs harmful particles or old organelles, it can fuse with a lysosome. The lysosome’s enzymes will then degrade these materials, recycling usable components and disposing of waste. This also contributes to the overall maintenance of the cell by preventing the buildup of damaged or excess materials.
Lysosomes also help in processes like apoptosis (programmed cell death), where they break down parts of the cell that need to be dismantled. Additionally, they are involved in processes like autophagy, where a cell consumes its own components, often to survive under stress or nutrient deprivation.
These organelles are crucial for maintaining homeostasis within the cell, ensuring that metabolic processes run smoothly and that the cell can efficiently deal with waste and potentially harmful materials. In summary, lysosomes are essential for the cell’s cleanup and recycling functions, making them a vital part of cellular maintenance and function.