What is the difference between mitochondria and plastids?

PLASTIDS:
Plastids are cell organelles, found only in plant cells.
There are three major types:
1. Chloroplast: (Chloro- green)
Also called as the "kitchen of plant cells".They are plastids containing a green-colored pigment, named "chlorophyll". In the presence of sunlight, a plant converts carbon dioxide, using water and chlorophyll into carbohydrates (mainly starch). This serves as the source of energy to plants.
2. Chromoplasts: (Chrome-color)
These are plastids containing colored pigments, other than chloroplasts, which imparts colors to the flowers and fruits.
For example, xanthophyll imparts yellow color; Carotene imparts orange color.
3. Leucoplasts: (Leuco -white)
These are mainly colorless plastids. Their min function is to store food in the form of starch and oils in the plant cell.
MITOCHONDRIA:
A mitochondria, is also called as the "Powerhouse of the cell".
As we now know, plants make their food in the form of starch. This starch is oxidized (reacts with oxygen) inside the mitochondria to produce these by products:
1. ATP (Adenosine Trip-phosphate) - also known as the Energy currency of cell
2. Carbon dioxide and water : Given out by plants as a result of respiration.
Thus the basic differences in plastids and mitochondria are as follows:
Plastids:
1. Found ONLY in plant cells
2. Plastid, especially Chloroplast, is called the Kitchen of the plant cell
3. Food in the form of starch is produced.
4. Contain many pigments.
5. Only Chloroplasts have their own DNA

Mitochondria:
1. Found in BOTH animal and plant cells
2. Also known as the powerhouse of cell.
3. Food produced in form of starch, is oxidized into ATP.
4. Do not contain pigments.
5. Have their own DNA

A plastid is not necessarily a specific cell organelle in the way that a mitochondrion is. A plastid is a category of organelle. A chloroplast would be a specific type of plastid, but not all plastids are photosynthetic. A plastid is a double membrane-bound organelle that is found inside plants (and some algae), and they are responsible for activities related to making and/or storing food. The above description points out a couple of key differences between plastids and mitochondria. Plastids are not found in animal cells. Mitochondria are found in both plant and animal cells. Another main difference between the two organelles is their purpose. Plastids are designed to produce food, and mitochondria are designed to use that food in order to produce adenosine triphosphate (ATP).