IGCSE Science/Section 2: Structures and functions in living organisms/Cell structure
Cell organelles: Small structure having definite shape and performing specific functions
They are embedded in the cytoplasm, These structures are called cell organelles. Most cells have these organelles:
|It regulates all important activities of the cell and plays an important part during cell division.
|a place for chemical reactions to happen, and it contains enzymes which speed up these reactions
|It allows only certain substances to pass through small pores on it and protects the inner cell contents.
|It perform cellular respiration, referred as powerhouse of the cell.
Plants cells have:
|Cellulose cell wall
|It gives a definite shapes to the cell , allows all substances to pass through it and protect the inner cell contents called protoplasm.
|They are of 3 types:
i)Chloroplast- It can trap solar energy and covert it into chemical energy in the form of food through the process of photosynthesis. ii)Chromoplast-It contains coloured(red, yellow, orange)pigments that impart colour to flowers and fruits. iii)Leucoplast-It is colourless pigment that store food in the form of starch, proteins and fats.
|It stores sugar ,mineral and water in the form of cell sap and maintain the shape of cell.
Yeast cells have:
|Chitin cell wall
|to keep the structure of the cell
|to store nutrients and food
Animal cells only have the basic organelles, but plants have all the basic organelles and some more: a cell wall, chloroplasts and a vacuole: