CELL ORGANELLS

 CELL ORGANELLES

As mentioned earlier, cytoplasm contains many small structures called cell organelles or organelles. There are many types of organelles in the cell and they perform different functions.

Plastids

Plastids are found only in plant cells. They are surrounded by a double membrane. There are mainly three types of plastids.

Chloroplasts: These are also called green plastids because they contain the green pigment chlorophyll. They are present in the green parts of the plant. Chlorophyll traps the solar energy to prepare food for the plants. Hence, chloroplasts are o ralted the "kitchen of the cell

 Chromoplasts :These are coloured plastids. They are found mostly in fruits and flowers. Yellow, orange, red and other colours of fruits and flowers are due to the presence of chromoplasts

Outer membrane

membrane

Leucoplasts: These are colourless plastids. They are found in roots and underground stems like potato and ginger. They store food prepared by the plant in the form of starch , proteins and fats.

Vacuoles

Vacuoles are sac-like structures containing a fluid called cell sap. They are bound by a single membrane called tonoplast. Plant cells have large vacuoles whereas animal cells have many smal vacuoles. Some plant cells have only one large vacuole while some animal cells do not have any vacuole.

Functions

Vacuoles maintain the turgidity of a cell, that is, the cell remains in shape. They store food (sugars, proteins, amino acids and minerals), water and wastes

Functions of Different Cell Organelles

Functions

Stores excess water, useful materials, pigments and waste products

Chloroplasts (green plastids) contain chlorophyll which is necessary for photosynthesis, leucoplasts store food material, especially starch and chromoplasts contain pigments other than chlorophyll also Cont. It helps in transfer of characters from parents to their offspring It plays an important role in cell divis

DIFFERENCES BETWEEN PLANT AND ANIMAL CELLS The basic structure is same in all plant and animal cells. Both have plasma membrane, cytoplasm, nucleus and cell organelles. However, they show some differences. For example, plant cells have a rigid cell wall outsidethe plasma membrane which is absent in animal cells. The differences between plant and animal cells are given in the following table.