MOLECULAR AND THEIR INTERACTION RELAVENT TO BIOLOGY

BIOCHEMISTRY NOTES  

MOLECULAR AND THEIR INTERACTION RELAVENT TO BIOLOGY

1. STRUCTURE OF ATOMS,MOLECULES AND CHEMICAL BONDS.

BULLET POINTS:

• ATOMS ARE SMALLEST MOLECULES WHICH WE COME ACROSS OFTEN.
• AN ATOM CONTAINS  PROTON, NEUTRONS AND ELCTRONS.
• MOLECULES AGGREGATES THE ATOMS IN A PARTICULAR MANNER.
• THE AGGREGATION CALLS FOR BONDING: CHEMICAL BONDS
• THERE ARE MANY TYPES OF BONDS,NAMELY COVALENT BONDS,ELECTROSTATIC BONDS,COORDINATE BONDS,IONIC BONDS,VANDERWAAL FORCES ETC.

1.1 STRUCTURE OF ATOMS:

• The Atom is a basic unit of matter that consist of dense nucleus surrounded by cloud of negatively charged electrons.
• The Atomic Nucleus contains postively charged protons and electrically neutral Neutrons(except Hydrogen).
• The electrons of an Atom are bound to the nucleus by the Electromagnetic forces.
• An Atom containing An equal number of proton and Electrons is Electrically Neutral, otherwise it is Positively or Negatively charged and is known as an ion.
• An atom is classified According to the Number of protons and Neutrons in its Nucleus.
• The Number of protons determines the chemical element, and the number of neutrons determines the isotopes of the element.
• Chemical atoms, which carry simple name of"Atom" are minuscule objects with diameters of a few tenths of a nanometre and tiny masses proportional to the Volume implied by these dimensions.
• Atoms can only be observed individually using special instruments such as the scanning tunnelling microscope.
• Over 99.94% of an atom's mass is concentrated in the Nucleus. protons and neutrons having roughly equal mass.
• Each element has atleast one isotope with an unstable nucleus that can undergo radioactive decay.
• This results in transmutation that changes the Number of protons and neutrons in a nucleus.
• Electrons that are bound to atoms possess a set of stable energy levels, or orbitals and can undergo transition between them by absorbing or emitting protons that match the energy difference between the levels.
• The electron determine the chemical properties of an element, and strongly influence an atom's magnet properties.
• The Principle of quantum mechanics have been successfully used to model the observed properties  of the atom.

Table 1.1: Charge and Mass of Subatomic Particles

• In the Table, we have used a unit of mass called the Atomic Mass Unit (AMU).This unit is much more convenient to use than grams for describing masses of atoms.
• It is defined so that both protons and neutrons have a mass of approximately 1 amu.

IMPORTANT POINT TO NOTE:

• PROTON AND NEUTRONS HAVE ALMOST THE SAME MASS,WHILE THE ELECTRON IS APPROXIMATELY 2000 TIMES LIGHTER.
• PROTONS AND NEUTRONS CARRY CHARGES OF EQUAL MAGNITUDE, BUT OPPOSITE CHARGE.NEUTRONS CARRY NO CHARGE(THEY ARE NEUTRAL).

It was once that proton,neutrons and electrons were spread out in a rather uniform fashion to form the atom.

J.J.THOMPSON'S PLUM PUDDING MODEL OF THE ATOM,but we know actual structure of the atom to be quit different.

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