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· Variation and Mutation
· Inheritance Part 2
· Inheritance Part 1
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· Introduction of Cell Biology
· Cell Structure Part 1
· Cell Structure Part 2
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· Cell Molecules Part 1
· Cell Molecules Part 2 - Organic Molecules
· Cell Molecules Part 3 - Proteins
· Cell Molecules Part 4 - Enzymes
· Cell Division Part 1
· Cell Division Part 3

Current Location > Biology Topics > Cell Biology > Cell Molecules Part 1

Cell Molecules Part 1

Cell Molecules Part 1:
Cell contains various organelles and different kinds of molecules which are responsible for metabolic activities carried out by cells. Metabolic activities are result of various biochemical reactions. Cells contains two types of materials

Inorganic molecules – water, mineral salts, mineral ions etc
Organic molecules – carbohydrates, lipids, proteins etc.

Inorganic molecules:

Water:

Water is an important constitution of any living organism as it plays a crucial role in all physiological activities. Living organism contains 65% or more water in their body and in living cell, it may be 70 to 90 % of its volume.

Properties of water:

Act as a solvent – It acts as a solvent and dissolves many chemicals to maintain the homogeneity of cytoplasm
Transport medium – It acts as a transport medium for various chemicals and transports them from higher concentration to lower concentration. It is essential for all biochemical activities performed by cell.
Polarity – Water contains hydrogen and oxygen molecules bound with one another by hydrogen bond. Because of these property water molecules possesses polarity and get arrange around positive or negative charge ions and include them within.
Cohesive force – Water molecules are having high cohesive force amongst hem which holds them together and plays an important role in process of ascent of sap in plants. Ascent of sap is the process of movement of water molecules absorbed by root system of plants towards the stem and the leaves and occurs against the pull of gravitation.
Latent heat – water has high specific and latent heat which do not allow large temperature changes inside the cell
Water plays an important role in maintaining three dimensional forms of macromolecules like nucleic acids, lipids, proteins etc.
Water acts as a reactant and provides H⁺ and OH^- ions for many reactions.
Water contains potential energy which helps organism for their growth and reproduction.

Mineral salts:

Cells contain various mineral salts associated with inorganic and organic molecules. There are two types of mineral salts are present in the cell – macromitrients and micromitrients.

Types of mineral salts:

Macromitrients – mineral elements are present in large amount.

Example – Calcium, sodium, chlorine, phosphorus, magnesium, Sulphur etc

Micromitrients – mineral elements are present in extremely small amount.

Example – Copper, iron, cobalt, manganese, zinc, iodine, molybdenum, selenium etc.

Importance of mineral salts:

Mineral salts	Importance of mineral salts
Sodium	Maintain the pH of cell Maintain the osmotic pressure of intracellular fluids
Calcium	Essential for bones and teeth Helps in clotting of blood Contraction of muscle
Magnesium	Essential component of ATP Require for glucose metabolism
Potassium	Conduction of nerve impulse Maintenance of pH
Iron	Present in hemoglobin and helps in respiration Structural component of many enzymes
Molybdenum	Associated with enzymatic reaction and helps in nitrogen fixation
Iodine	Development of thyroid gland
Phosphorus	Essential for teeth and bones Present in ATP and nucleic acid
Chlorine	Present in blood and helps in transport of oxygen and carbon dioxide

Self study:

Example-1: Match the following

A	B
Calcium	Maintenance of pH
Sodium	Nitrogen fixation
Iodine	Contraction of muscle
Molybdenum	Development of thyroid gland

Answer:

A	B
Calcium	Contraction of muscle
Sodium	Maintenance of pH
Iodine	Development of thyroid gland
Molybdenum	Nitrogen fixation

Example-2: Water plays an important role in maintaining ………….structure of macromolecules.
a) Two-dimensional
b) Four-dimensional
c) Three- dimensional
d) None

Answer: Water plays an important role in maintaining three-dimensional structure of macromolecules.

Example-3: ……………of water plays an important role in process of ‘ascent of sap’.
a) Cohesive force
b) Adhesive force
c) Latent heat
d) Polarity

Answer: Cohesive force of water plays an important role in process of ‘ascent of sap’.