The Fundamental Unit of Life

Mitochondria is a cell organelle found in almost all eukaryotic cells. Mitochondria generate energy which is necessary for life processes through aerobic respiration. Respiration takes at the cellular level in mitochondria. Hence, the MITOCHONDRIA IS KNOWN AS THE POWERHOUSE OF THE CELL.

Mitochondria has a spherical to oval shape. Mitochondria are covered with two layers of membrane. The outer layer of the membrane of mitochondria is spherical and porous while the inner layer of mitochondria has folded shape. The folded shape of the inner membrane of mitochondria facilitates enough space to release energy necessary for life. Mitochondria are the only cell organelles that have their own DNA and ribosomes. With this special structure, mitochondria are able to make some of their own proteins.

The number of mitochondria varies from cell to cell and tissue. Muscles and liver cells may have hundreds to thousands of mitochondria while red blood cells do not have mitochondria.

The Mitochondria was discovered in 1857 by a Swiss scientist Albert von Kolliker.

We require energy for survival and other all activities. This energy is produced by mitochondria found in the cytoplasm of the cells. Mitochondria produces energy by using nutrients in the form of glucose. Mitochondria burns or decomposes glucose in the presence of oxygen and releases energy which is used for the various life processes. This energy released by mitochondria is in the form of Adenosine Triphosphate. Adenosine Triphosphate is popularly abbreviated as "ATP".

Along with producing energy, mitochondria store calcium, generate heat and plays important role in the growth and death of the cell. Calcium is used for cell signaling.

Mitochondria is a unique cell organelle that has a double layer of membrane, and has its own DNA and ribosomes.

Plastids

Plastid is a membrane bound cell organelle only found in plant cells. There are mainly two types of plastids, viz. chromoplasts and leucoplasts.

Chromoplasts

Chromoplats are the coloured plastids found in plant cells. Chromoplasts synthesise and store colour pigments in the different parts of the plant. Chromoplasts give the characteristic colour to the leaves, fruit, and flower of plants.

Chloroplasts

Chromoplasts containing the pigments are known as Chloroplasts. Chloroplasts further can be divided into two types. These two types of chloroplasts are chlorophyll and carotenoids.

Chlorophyll

Chlorophyll is a pigment that gives green colour to the plant. It is mainly found in the leaves of the plant. Because of the chlorophyll, the leaves of a plant look green.

It is the chlorophyll because of which photosynthesis takes place in a plant. Photosynthesis is the synthesis of food using sunlight, carbon dioxide, and water.

Carotenoids

A group of natural pigments found in plants is known as Carotenoids. These pigments are yellow, orange, and red. Carotenoids give characteristic colours to the fruits, flowers, buds, and roots of a plant. This specific colour enables flowers to attract insects that are necessary for pollination.

A particular type of fruit, such as papaya has a particular type of colour due to carotenoids. A fruit changes its colour after ripening because of carotenoids.

Stroma

The fluid filled internal space of chloroplasts is known as stroma. The stroma contains starch, chloroplasts DNA and ribosomes similar to mitochondria.

The process of photosynthesis starts in the stroma.

Leucoplasts

Leucoplasts are the plastids that stores materials such as starch, oil, proteins, etc. in plants. Leucoplasts are non-pigmented plastids in contrast with chromoplasts. Leucoplasts do not contain chlorophyll because of this it does not take part in photosynthesis and hence are present in non-photosynthetic tissues of plants. Leucoplasts are generally found in the roots, bulbs, and seeds of a plant.