The story of how mitochondria and chloroplasts got their own DNA

 Certainly! The story of how mitochondria and chloroplasts got their own DNA is tied to a fascinating evolutionary process called the endosymbiotic theory.

The Origin of DNA-Containing Organelles:

Millions of years ago, the ancestors of modern eukaryotic cells (cells with a nucleus) didn’t have mitochondria or chloroplasts. Instead, they were simple cells that relied on different methods to produce energy.

1. The Symbiotic Invasion – At some point, a large primitive cell engulfed smaller bacteria. But instead of digesting them, the host cell formed a partnership with them. These bacteria had special abilities—the ones that eventually became mitochondria could efficiently generate energy, while the ones that became chloroplasts could carry out photosynthesis.

2. Survival Advantage – This was a win-win situation! The host cell provided protection, while the engulfed bacteria provided energy. Over time, these bacteria became permanent parts of the cell, evolving into the organelles we see today.

3. Why They Kept Their DNA – Even though mitochondria and chloroplasts are now part of the cell, they retain their own DNA because they still produce some of their own proteins and replicate independently. However, some of their genes have been transferred to the nucleus over time.

This theory is strongly supported by evidence like:

• Mitochondria and chloroplasts have circular DNA, just like bacteria.

• They divide on their own inside the cell (similar to bacteria reproduction).

• They have their own ribosomes, which resemble bacterial ribosomes.

So, in a way, your cells carry tiny remnants of ancient bacteria inside them, still working tirelessly to keep you alive. Evolution really is full of surprises! 😃

Nutrition in human being

Human Nutrition & Digestive System

Mouth

Function: There are three things present inside the mouth teeth, tongue and salavery gland. The function of teeth is to break down the food into smaller parts. The salavery gland release salavery amalese which helps in degestion of starch and the fuction of tounge is to mix the saliva with food.

Oesophagus

Function: The oesophagus transports food from the mouth to the stomach using rhythmic contractions called peristalsis.

Stomach

Function: The stomach has gasteric gland which secretes hydrochloric acid and pepsin. The function of acid is to make food acidic so the pepsin can acts on it.The pepsin helps in digestion of protein. The food is churned into a semi-liquid form called chyme.After that this chyme moves into small intestine with the help of sphincter muscle.

Small Intestine

Function: In the small intestine, the bile juice is secreted from the liver, which contains bile salt, which helps in the emulsification of fat. And another function of bile juice is to make food alkaline. The pancreatic juice is also secreted into the small intestine by the pancreas, which contains lipase and trypsin. The function of lipase is to break down emulsified fat, and the function of trypsin is to digest protein. The wall of the small intestine releases intestinal juice, which converts fat into fatty acids, carbohydrates into glucose, and protein into amino acids. The wall of the small intestine contains villi, which contain blood capillaries. The function of villi is to absorb digested food and transport it into the blood.

Large Intestine

Function: The large intestine absorbs water and minerals from undigested food and prepares waste for excretion.