MCQ Detailed View

The mitochondria are known as the powerhouses of the cell because they are responsible for producing the majority of the cell's energy in the form of adenosine triphosphate (ATP). Every cell in living organisms requires energy to perform essential functions like growth, repair, division, and biochemical reactions. This energy is generated primarily inside mitochondria through a process called cellular respiration.

How Mitochondria Produce Energy:

1. 
   

   Glucose Breakdown: Nutrients from food, mainly glucose, are transported to the mitochondria.

   
   


2. 
   

   Oxidative Phosphorylation: Inside mitochondria, glucose undergoes a series of reactions with oxygen in the Krebs cycle and electron transport chain, producing ATP molecules.

   
   


3. 
   

   ATP Supply: ATP acts as the energy currency of the cell, fueling all biological processes.

   
   

Mitochondria have their own DNA and ribosomes, allowing them to produce some of their own proteins and enzymes required for energy production. This is why mitochondria are sometimes called semi-autonomous organelles.

Why Other Options Are Incorrect:

• 
  

  Vesicles: These are small sacs that transport materials within the cell but do not produce energy.

  
  


• 
  

  Lungs: Organs that facilitate gas exchange in animals, supplying oxygen but not directly generating ATP at the cellular level.

  
  


• 
  

  Liver: A vital organ for metabolism and detoxification but not a cellular organelle producing energy.

  
  

Mitochondria are particularly abundant in muscle cells, heart cells, and brain cells, which have high energy demands. Without mitochondria, cells would not be able to generate sufficient ATP, leading to loss of function or death.

Thus, the correct answer is Mitochondria (Option A), the true powerhouses of the cell that supply energy for life processes.