Classification of silicates into various types is summarized in below
PART OF CELL MAIN CHARACTERISTICS CHIEF FUNCTION(S)
1. Plasma membrane(also called as membrane). 1.Outermost in animal cells.
2.Lies next to cell wall in plants.
3.Very thin, flexible, living membrane.
4.Possess fine pores.
5.Semi-permeable.
6.Made up of lipoproteins.		 1.Regulates the entry of certain solutes and ions.
2.Maintains shape of the cell.
2. Cell wall (plant cells only) 1.Non-living rigid layer surrounding plasma membrane.
2.Mainly composed of cellulose.
3.Freely permeable.		 1.Gives rigidity and shape to the cell.
2.Allows substances in solution to enter and leave the cell without hindrance.
3.Provides protection.
3. Cytoplasm 1.All the parts together in the plasma membrane excluding nucleus.
2.Contains a mixture of water and soluble inorganic and organic compounds, and various organelles.		 1.Different organelles contained in it perform different functions.
2.All metabolic activities occur in it.
4. Endoplasmic recticulum(ER) 1.Irregular network of tubular double membrane.
2.It is continuous with the plasma membrane on the outside and the nuclear membrane on the inside.
3.May be smooth or rough (attached ribosomes).		 1.Supportive framework for the cell.
2.Synthesis and transport of proteins and fat.
5.Mitochondria 1.Various shapes but usually sausage-like.
2.Double walled: inner wall thrown into folds (cristea).		 1.Release of energy from food in the form of ATP (Seat of cellular respiration and stores energy).
2.Synthesis of respiratory enzymes
6.Golgi apparatus (in animal cells) (called dictyosomes in plant cells) 1.Stacks of flattened membrane sacs.
2.Consists of tubules, vesicles and vacuoles.		 1.Synthesis and secretion of enzymes, hormones, etc.
2.Formation of acrosome of sperm.
7.Ribosomes 1.Small granules either scattered in the cytoplasm or attached to the outside of endoplasmic recticulum.
2.Single walled dense, spherical bodies composed mainly of RNA.		 1.Protein synthesis.
8.Lysosomes 1.Membranous sacs budded off from Golgi body.
2.Contains 40 different types of enzymes.		 1.Intracellular digestion
2.Destroy foreign substances.
3.When cell is old or injured, these rapidly destroy organelles(hence called "suicide bags").
4.Formation of bones by digesting cartilages.
9.Centrosome(Animal cells only) 1.Located near nucleus
2.Contains one or two centrioles are surrounded by microtubes or centrosphere.		 1.Initiates and regulates cell division.
2.Forms spindle fibres, with the help of asters.
10.Plastids(Plant cells only) 1.Several kinds, most common ones are chloroplasts containing the green pigment chlorophyII.
2.Double membraned, protein aceous matrix, contain DNA.
3.Disc like structures called thylakoids contain chlorophylI.		 1.Chromoplasts – Impart colours to flowers and fruits
2.Chloroplasts (green) – trap solar energy for photosynthesis.
3.Lecoplast-stores starch.
4.Anthocyanin pigment is dissolved in cytoplasm (blue-violet colour).
11.Nucleus 1.Largest cell organelle.
2.Mostly spherical and dense.
3.Nuclear membrane with pores to allow substances to enter and leave.
4.Contains network of thread-like structures called chromatin fibres which contain DNA. 		1.Involved in division.
2.Regulates cell functions.
3.If removed, the cell dies.
4.Contains chromosomes (bearers of characters called genes).
12.Nucleolus 1.One or more round-shaped nucleoli inside the nucleus. 1.Produces ribosomes.
2.Participates in protein synthesis by forming and storing RNA.
3.Dictates ribosomes to synthesise proteins.
13.Chromatin fibres 1.The network in resting stage of the nucleus condenses into chromosomes during cell division.
2.Made up of DNA threads.		 1.Chromosomes carry hereditary information or the genes.
14.Vacuoles 1.Clear spaces with water or other substances in solution.
2.Plant cells have larger vacuoles, while the animal cells have fewer and smaller ones.
3.Covered by a membrane called tonoplast.		 1.Storage of water and other substances, pigments, and waste products.
2.Give turgidity to the cells
15.Granules 1.Small particles, crystals or droplets. 1.Starch (in plant cells),glycogen (in animal cells) and fat containing granules serve as food for the cell.