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:Cell organelle are the components of the cell which perform various functions of the cell. They can be without a membrane or with a membrane. One of the cell organelles is known as the powerhouse of the cell whereas the other cell organelle is also known as the kitchen of the plants.

Complete answer:
The cell is the basic structural and functional unit of life. Organisms can be classified based on the presence of nuclear membrane. In a prokaryotic cell, there is no well-defined nucleus whereas in eukaryotes the nucleus is well defined enclosed by a nuclear membrane. The cells provide shape and structure to the various parts of our body. It consists of some structural units which are called organelles. These organelles can be membrane bound or without membranes. All the organelles perform different specific functions. So, the organelles present in the cells can be divided into three types based on the membrane. They are:
Cell organelles without membranes
Cell organelles with single membranes
Cell organelles with double membranes
The organelles with double membrane are present in the eukaryotes and are- nucleus, mitochondria and chloroplast.

Mitochondria: It is also known as the powerhouse of the cells as they produce energy for the cell to perform various cellular activities.
>This energy is stored in the form of ATP which stands for adenosine triphosphate.
>It is a double membrane structure shaped like a sausage. The double membranes divide the mitochondria into two compartments.
>The inner compartment is called a matrix. The matrix consists of various enzymes, ribosomes and proteins.
>The matrix contains various folds known as cristae. These folds increase the surface area for carrying out various energy related processes.
>The outer membrane forms the boundary of it and helps in exchange of various substances.
>The space between two membranes is called an intermembrane space.

Chloroplast: They are called the “cook house” or kitchen of the plants which perform the photosynthesis due to the presence of chloroplast pigment.
>This pigment helps in the process of photosynthesis by absorbing the sunlight. The structure of chloroplast includes two membranes and can be of various shapes such as discoid, spherical, or ribbon like.
>The space inside the inner membrane is called a stroma which contains flat disc shaped structures called thylakoids.
>These thylakoids pile up like stacks of coins and are called granums. These grana are joined together using flat tubules known as stromal lamella.
>The stroma consists of various enzymes, proteins and DNA.

Note:Mitochondria and chloroplast are the two double membrane bound organelles. They play an important role in various cellular activities. Such as the chloroplast contains the green pigment which is necessary for the process of photosynthesis. On the other hand, the mitochondria is the energy producer which produces energy currencies known as the ATP.