“Mitochondria is the powerhouse of the cell”
Does this ring any bells?
Childhood memories have faded for most of us. While we remember the important details, the happiest times of those days and the sad (if there were any), there must be a gazillion things (mostly the mathematical formulas and other lessons we learnt in school) we have forgotten. But what we will never forget is this one thing we learnt in biology class. It still remains fresh in our memories. Isn’t it?
Feel nostalgic yet? We are certain you. This blog will take you down the trip and learn more about mitochondria. Let’s see how many of you still remember what mitochondria are and their functions in the body.
Brushing the basics
As you can recall, mitochondria, being the powerhouse of the cell provide the cells with energy. But there’s more than meets the eye. In simple words, mitochondria have several other functions to perform in the body.
Functions of mitochondria
The Energy Factories of the Cell
Mitochondria break down nutrients and convert them into energy through a process called oxidative phosphorylation. This complex process involves a series of chemical reactions that ultimately produce ATP, the energy currency of the cell.
How Do Mitochondria Produce Energy?
The process by which mitochondria produce energy is a bit complex but fascinating. Here’s a simplified overview:
Glycolysis:
This first step happens in the cytoplasm of the cell where glucose is broken down into smaller molecules called pyruvate. This doesn’t happen inside the mitochondria but is crucial for the next steps.
Citric Acid Cycle (Krebs Cycle):
Once pyruvate enters the mitochondria, it gets converted into acetyl-CoA and enters the citric acid cycle. Here, it undergoes several reactions, producing energy-rich molecules like NADH and FADH2.
Electron Transport Chain (ETC):
These energy-rich molecules then enter the inner membrane of the mitochondria. The electron transport chain is a series of reactions that occur across the inner membrane. Electrons are transferred through a chain of proteins, and this transfer helps in pumping protons across the membrane, creating a gradient.
ATP Production:
The energy from the proton gradient is used to produce ATP (adenosine triphosphate), which is the main energy currency of the cell. This happens in a process called oxidative phosphorylation.
Other functions
Cellular Health:
Mitochondria also play a role in controlling the cell’s life cycle. They are involved in processes that regulate cell death (apoptosis), which is essential for removing damaged or unwanted cells.
Metabolism:
They help regulate various metabolic pathways and are involved in the synthesis of certain hormones and neurotransmitters.
Stores calcium
Calcium is essential for various cellular functions. For example, its release into a cell can trigger the discharge of neurotransmitters from nerve cells or hormones from endocrine cells. Additionally, calcium plays a crucial role in muscle activity, fertilization, and blood clotting, among other processes.
Given its importance, cells tightly regulate calcium levels. Mitochondria contribute to this regulation by swiftly taking up calcium ions and storing them until they are needed.
Calcium also influences other cellular activities, such as controlling metabolism, steroid production, and hormone signalling.
Helps in Heat Generation
When we are cold, we often shiver to generate warmth. However, the body has additional mechanisms for producing heat, one of which involves brown fat tissue.
Mitochondria can create heat through a process known as proton leak, which is part of non-shivering thermogenesis. Brown fat, which is most prevalent in infants—who are more vulnerable to cold—gradually diminishes with age.
Mitochondrial DNA: A Unique Feature
One of the most interesting aspects of mitochondria is that they have their own DNA, separate from the DNA in the cell nucleus. This mitochondrial DNA (mtDNA) is inherited solely from the mother and contains genes important for mitochondrial function. It’s like mitochondria have their own set of instructions on how to operate and replicate.
Closing thoughts
Mitochondria might seem like a simple concept in our school science classes, but their role is far from mundane. These tiny organelles are integral to our health, providing the energy our cells need to function and survive. So next time you recall mitochondria, remember the pivotal role it has in our body.
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