Unit 1: Life components
Cellular pool:
The cellular pool is the collection of diverse types of biomolecules, chemicals, and ions
present in a cell. Many different types of inorganic and organic biomolecules make up a
living organism. Inorganic compounds, such as water and minerals, are always micro-
biomolecules (small in size, low in molecular weight, easily soluble in water, and
diffusible). In contrast, organic molecules can be micro (e.g. monosaccharides, amino acids,
etc.) or macro (e.g. polysaccharides (large-sized, high molecular weight, insoluble or
slightly soluble and non-diffusible, e.g., proteins, fats, nucleic acids, etc.).
Phases of Cellular pool
There are two types of it: aqueous and non-aqueous.
1. Aqueous phase: Chemicals distributed in water create a true or colloidal solution in the
aqueous phase. Crystalloids are substances that create true solutions, while colloids are
substances that make colloidal solutions. A true solution is homogeneous in nature with a
particle size of 1 nm or less, while the colloidal solution is heterogeneous with particle size
1-100 nm.
2. Non-aqueous phase: Chemicals are deposited in diverse structures such as chromatin, cell
membrane, and cell wall in the non-aqueous phase. Living and non-live matter are both
made up of the same sorts of elements. Still, the relative abundance of C and H in relation to
other elements is larger in any living thing than in non-living matter or the earth’s crust.
Biomolecules
Biomolecules are organic molecules that are involved in the structure, function, and regulation of
living organisms. They are the building blocks of life, playing a vital role in the maintenance and
metabolic processes of cells. Common biomolecules include carbohydrates, proteins, lipids, and
nucleic acids.
Macromolecules
Macromolecules are large, complex biomolecules with high molecular weights. They are
typically formed by the polymerization of smaller subunits called monomers. The four main
classes of macromolecules in biology are:
1. Proteins: Made up of amino acids linked by peptide bonds. They serve numerous
functions, including acting as enzymes, structural components, and signaling molecules.
2. Nucleic Acids: DNA and RNA, composed of nucleotide monomers. They carry genetic
information and are essential for protein synthesis.
3. Carbohydrates: Polysaccharides like starch and cellulose are macromolecules formed by
monosaccharides (simple sugars) linked in chains. They provide energy and structural
support.
4. Lipids: Although not always polymers, some lipids, like triglycerides and phospholipids,
are considered macromolecules due to their large size and structural complexity. They are
key in storing energy and forming cell membranes.
Micromolecules
Micromolecules are small, low molecular weight compounds that serve as building blocks or
serve vital roles in metabolism. They include:
1. Monosaccharides: Simple sugars like glucose and fructose, which are the monomers for
carbohydrates.
2. Amino Acids: Small molecules that combine to form proteins.
3. Nucleotides: The building blocks of nucleic acids like DNA and RNA.
4. Fatty Acids and Glycerol: Basic units of lipids.
5. Vitamins and Minerals: Essential for various biochemical reactions within the body.
Constituents of Cellular Pool
The cellular pool consists of various substances. They can be categorized into two types of
constituents: Inorganic and Organic. Inorganic substances are those that do not contain
carbon in addition to hydrogen. Carbon and hydrogen are found in organic.
Inorganic Constituent
Inorganic biomolecules do not contain carbon-hydrogen (C-H) bonds. They are simple molecules
and ions that are also essential for life processes. Examples include:
1. Water: 70% to 90% of the cellular pool is made up of water. It makes up 65 per cent (about
two-thirds) of the human body. In the cell, 95 per cent of the water is in its state, while just
5% is in its mixed form. Water aids in the maintenance of life processes. Be a result, water
is referred to as an elixir or cradle of the lips, as life cannot exist without it.
2. Oxygen: Oxygen is required for life since it is primarily used in aerobic cell respiration of
nutrients inside the mitochondria to make energy-rich ATP molecules. Only 5% of the
energy available is released when there is no oxygen present.
3. Inorganic Acids, Bases, and Salts: Substances like hydrochloric acid (HCl) in the stomach aid
digestion, while salts like sodium chloride (NaCl) help regulate fluid balance and nerve function.
4. Minerals: Inorganic elements like calcium, potassium, sodium, magnesium, iron, zinc, and
phosphorus. They play various roles, such as maintaining bone health (calcium), nerve impulse
transmission (sodium, potassium), and oxygen transport (iron).
Organic Constituent
Organic biomolecules are carbon-containing compounds typically found in living organisms.
These molecules are the building blocks of life and are characterized by the presence of carbon-
hydrogen (C-H) bonds. The main classes of organic biomolecules include:
1. Carbohydrates: Carbohydrates are organic substances made up of the elements C, H, and O
in a 1:2:1 ratio. Saccharides are the common name for these sugars. Carbohydrates are the
most common storage molecules, and most organisms use them as a source of energy by
breaking these bonds and releasing energy to keep them alive.
2. Proteins: Proteins are polymeric molecules made up of amino acids linked together by
peptide bonds. Only roughly 20 amino acids are biologically significant out of a total of
about 100. Proteins are essential for the development of structures in living organisms.
Protein, like carbohydrates and fats, maybe broken down when energy is released. Protein is
not stored in the body and is generally only used as a significant source of energy in times
of hunger.
3. Lipids: Lipids are a large category of insoluble hydrocarbons that serve a variety of
functions. These polymers are made up of alcohols (such as glycerol) and fatty acids bonded
together by ester bonds. True fats, for example, are complex lipids that are vital chemical
compounds that give energy. Animal fats also offer insulation against heat loss.
4. Nucleic Acid: Polynucleotides are polymers of nucleotides interconnected by
phosphodiester linkages and referred to as nucleic acids. Each nucleotide is made up of
three parts: a pentose sugar (ribose in RNA and deoxyribose in DNA), a phosphate group,
and an inorganic nitrogen-base (a purine or a pyrimidine). In most organisms, DNA serves
as the genetic material and regulates the production of structural and functional proteins. In
all plant viruses, such as TMV, RNA serves as genetic material and aids in protein
synthesis.
