CELL STRUCTURE AND FUNCTION
Some basic
concepts of cell chemistry
The Nature of atom
As we all know that atom is the
smallest compound identity of any type of matter present in the universe. The
nature of atom is always same for every fundamental biological or physical unit
only the characteristics of the atom differ. Atom is further divided into three
fundamental particles namely proton, neutron and electron.
Chemical bonds
Chemical bond is a simple structure
of binding of atoms and molecules which forms the skeletal structure of matter.
Bond is nothing but a shared electron or electrons which bind two atoms or
molecules.
There are three types of bonds on
basic field of classification but there are only two of them in our concern
1)
Covalent bond
The bond in which a pair of electron
is shared by the atoms is called a covalent bond this can be explained by a
simple example of the two atoms of hydrogen molecule. Although both the atoms
are electrically neutral but at very close range negatively charged electron of
both the atoms are attracted towards the positively charged core of both the
atoms resulting in sharing of valence electrons to maintain the balance of
electromagnetic forces. Now if there are two pairs of shared electrons it is
termed as double covalent bond and the very case is involved in three shared
pair namely triple covalent bond. In the covalent bond of the two H atoms of H2,
the electron pair is shared equally and is symmetrical so therefore because of
its pole line symmetry it is called polar covalent bond but there are also non
polar bonds , this bond can be seen in CH4 atom where hydrogen bond
is not in not in a symmetrical order.
 |
| covalent bond in hydrogen |
Ionic Bond
The bond where the magnetic pull of
one atom‘s electron is so much that the electron of other atom is directly
transferred to the other atom of the first resulting in unequal shearing of
electrons. This bond is very strong and electromagnetic energy is evolved in
the process with same ionic energy or charges.
Acid, Base and ph value
(Now if someone finds it boring may
skip this) Acids are the substance that is the donor of +hydronium ions in a
reaction. Some common examples are Hydrochloric acid, Sulphuric acid and many
more. Whereas bases are the substances which accept a –hydroxyl ion in a
reaction.
Now let us take simple example
HCL + H2O THAT
IS H3O+
+ CL-
Here HCL is a strong acid which reacts which
reacts with water to for 3ioned water of positive charge and chlorine of
negative charge.
Now that’s done for chemistry lets go
to next topic
Energy and enzymes
The concept of energy is same in every
case whether it is chemistry or physics. In cell energy is provided by a
combination of certain chemical reaction which is called metabolic process.
Reactions carried in cell are of two types Exergonic and Endergonic. The reactions
which occur spontaneously are known as exergonic reaction. Whereas the reaction
in which certain amount of energy is required to carry out the reaction is
called endergonic reaction this reaction can carried out by supply of oxygen or
by some other means of energy or fuel.
The basic power shuttle of cell is
adenosine triphosphate (ATP) which is converted to adenosine diphosphate (ADP) an
inorganic phosphate. As ATP has more energy than ADP so a huge amount of energy
is realized in this conversion cycle
Enzymes
Now when we talk about a series of
reaction in cell it must be carried out in order to obtain something useful in
product. These reactions are carried out in a sequential manner called as plex
series and this series is conducted by a set of special kind of proteins which
lower the energy barrier to specify reactions and thereby directing the flow of
energy through specific channel. These proteins are called enzymes.
Thank you see more about cell in my
next chapter of cell structure and function. We will deal with the nucleus and
cell information next time
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