Macromolecules in cells



 Macromolecules in cell:

The macromolecules are large in size, have high molecular weights ( usually 10000 daltons and above), complex molecular structure and occur in colloidal state, being insoluble in intracellular fluid. They include only organic compounds, viz., polysaccharides, proteins and nucleic acids. They are formed by polymerization of large numbers of micromolecules. Macromolecules account for over 90% of the dry mass of cells.  Lipids molecules may be large, but are usually not large enough to be considered macromolecules. 



● Are large in size.
● Have high molecular weights.

● Have complex structure. 

● Occuras colloidal solution in the intracellular fluid.

● Formed by polymerization of micromolecules .

● Examples : only organic compounds ( polysaccharides,  proteins nucleic acids).


Common Macromolecules:

The most important macromolecules present in the cells are  polysaccharides, proteins and nucleic acids. These are chain _ like polymers formed by polymerization of micromolecules monomers, namely, sugars,   amino acids and nucleotides , respectively. Certain monomers also have other functions for their own.



Why are macromolecules important?

Macromolecules are crucial  to life as they play essential roles in various biological processes. There large molecules are made up of smaller subunits and include proteins, carbohydrates,  lipids , and nucleic acids (DNA and RNA). Here are some reasons why macromolecules are importan:

 1) Structure roles : Macromolecules provide the structural framework for cells and organisms. Proteins, for examples, are vital components of cell membranes, cytoskeleton, and tissues, giving cells their shape and stability. 

2) : Enzymatic functions: Proteins serve as  enzymes which are biological catalysts that facilitate and regulate chemical reactions in living organisms.  Enzymes are essential for metabolism,  signaling pathways, and numerous cellular processes.

3): Storage and energy:  Carbohydrates,  such as starch and glycogen, act, as energy reserves in plants and animals, respectively. Lipids also store energy and are crucial components of cell membranes. These molecules provide long__ term energy storage that cells can access when needed.

4): Genetic information:  Nucleic Acids ( DNA  and RNA) are responsible for storing and transmitting genetic information.  DNA  contains the genetic code that determines an organism's traits and characteristics. RNA  plays a critical role in translating the genetic information into functional proteins. 


5): Cell Communication: Cell surface carbohydrates and glycoproteins are involved in cell communication and recognition processes. They play roles in immune response, cell adhesion, and cell signaling.

6): Transport : Some proteins, like hemoglobin in red blood cells,transport essential substances like oxygen throughout the body. Lipids also facilitie the transport of fat__ soluble molecules and nutrients. 


7): Immune System Function: Antibodies, which are specialized proteins, play a crucial role in the immune system by recognizing and neutralizing for foreign invaders like bacteria and  viruses .

8): Cellular regulation:Macromolecules are involved in regulating various cellular processes, including gene expression, cell division,  and cell signaling pathways.

9): Enabling replication and cell division:
Nucleic acids, especially DNA, are essential for the replication and transmission of genetic information during cell division and reproduction. 

  Overall, macromolecules are essential for the structure, function, and regulation of living organisms. They are the building blocks of life and are fundamental to the functioning of cells and organisms in complex and intricate ways.

Biological macromolecules example  :

Biological macromolecules are large molecules that are essential for life and are composed of smaller subunits. Here are examples if each types of biological macromolecules:

1) proteins:

Example: Hemoglobin _ Found in red blood cells, hemoglobin is a protein responsible for carrying oxygen from the lungs to tissues throughout the body.

2):  Carbohydrates:

Examples: Glucose _ Glucose is a simple sugar and a primary source  of energy for cells. It is commonly found in fruits, vegetables, and other foods.

3):  Lipids :

Example: Triglycerides _ Triglycerides are a type of lipid found in fats and oils. They serve as a long _ term energy storage form in the body.

4): NucleicAcids: 

Example:  DNA  ( Deoxyribonucleic Acid) __ DNA is the genetic material that carries the hereditary information of an organism. It contains the instructions for building and maintaining the organism's structure and functions. 

5):  RNA ( RibonucleicAcid) _ RNA is involved in the process of protein synthesis by translating the genetic information from DNA and aiding in the synthesis of proteins. 

  Each of these macromolecules perform critical functions in living organisms, and  they work together to sustain life and ensure the proper functioning of cells and tissues. 



General Features of Macromolecules :

Being  polymers , the macromolecules are large, complex and have high molecular weights. However, they have poor solubility. In macromolecules, 

  (i) Covalent bonds between monomers are formed by elimination of water, a process called dehydration or condensation;
 
 ( ii) Formation of bonds requires energy and specific enzymes; and 

( iii) bonds between monomers are broken by addition of water, a process termed hydrolysis ( G.hydro = water, lysis = break).

  The macromolecules may be branched or unbranched.  Differences between human siblings are due to variations in polymers, specially DNA and proteins.  Molecular differences between unrelated individuals are greater and between species still greater. 

  For the formation of a bond between two monomers, one monomer provides a hydroxyle group ( ___ OH) and the other contributes a hydrogen ( __ H) to form water, which is lost. When a bond between two monomers breaks on addition of a water molecule, a hydrogen ( __ H) from water joins one monomer and a hydroxyle ( __ OH) attaches to the adjacent monomer.







































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