Question

Name two cell organelles that are double membrane bound. What are the characteristics of these two organelles? State their functions and draw labelled diagrams of both.

Answer 1

Hint: The cell organelles are involved in performing different functions. Mitochondria are a double membrane organelle that produces energy for the cell. Chloroplasts are double membrane organelles found in plant cells that help in photosynthesis.

Complete answer:
The cell is the basic building block of life. There are certain components within a cell called cell organelles that perform specific functions such as making new material in the cell, removing the waste material from the cell, etc. Because of these organelles, the cell is able to live and perform all its functions.
Each mitochondrion is a dual membrane-bound structure. The outer membrane is very porous and the inner membrane is highly folded. These folds have a large surface area for ATP-generating chemical reactions.

                                    Fig: Mitochondria

Mitochondria provides the energy required for various chemical processes crucial to life in the form of ATP (Adenosine Triphosphate) molecules. The body uses energy contained in ATP for the creation of new chemical compounds and for mechanical purposes.

Plastids are found in the plant cells. They are distinguished by the presence of pigments. On the basis of the pigment type, plastids can be classified as chloroplasts, chromoplasts and leucoplasts. Chloroplasts are bound by a double membrane. They can be circular, ovoid or discoid. The space confined by the internal membrane of the chloroplast is called stroma. A variety of structured flattened membrane sacs called thylakoids are found in the stroma. Thylakoids are placed in stacks called grana or intergranal thylakoids.Chloroplasts include chlorophyll and carotenoid pigments responsible for absorbing the light energy needed for photosynthesis.

                                           Fig: Chloroplast

Note:Each cell acquires its structure and ability to operate by arranging its membrane and organelles in a particular way. Thus, the cell has a specific structural organisation. This helps cells undertake tasks such as respiration, nutrition, waste disposal, or the production of new proteins.