Learning Objective
The learner will be able to,
• List out the inorganic and organic components of a cell.
• Understand about bonding pattern of water and properties of water.
• Familiarise with the classification of carbohydrates and its functions.
• Recognise the basic structure of carbohydrates, proteins, lipids and nucleic acids and differentiate the various pattern of classification with respect to structure.
• Identify the structure and functions of carbohydrates.
• Familiarise with the general structure of amino acids and its classification based on the functional group.
• Comparative study of the primary, secondary, tertiary and quaternary structure of proteins.
• Know the structure and classification of enzymes.
• Know about the factors affecting the mode of action of enzymes with relevant examples.
• Understand lipids as a biomolecule and discuss the properties of lipids.
• Have a deeper knowledge about structure of nucleic acids.
• Recognize nucleic acids as a polymer which plays a vital role in carrying the genetic information.
• Learn about the different forms of DNA and types of RNA.
Chapter Outline
8.1 Water
8.2 Primary and Secondary Metabolites
8.3 Carbohydrates – Classification and Structure
8.4 Lipids – Classification and Structure
8.5 Proteins and Amino Acids –
Classification and Structure,
8.6 Enzymes – Classification, Nomenclature, Structure and Concepts, Mechanism of Enzyme Action, Activation energy, factors affecting enzyme action.
8.7 Nucleic Acids general Structure and composition – Forms of DNA and Types of RNA.
Having learnt the structure of the cell, we can now understand that each component of the cell is responsible for a specific function. The cell components are made of collection of molecules called as cellular pool, which consists of
both inorganic and organic compounds.Inorganic compounds include salts, mineral ions and water.
Organic compounds are carbohydrates,lipids, amino acids, proteins, nucleotides,hormones and vitamins. Some organic molecules remain in colloidal form in the aqueous intracellular fluid. Others exist in non-aqueous phases like the lipid membrane and cell walls. The cell maintains this pool by the intake and elimination of specific molecules (Figure 8.1).
The minerals essential for plant growth are of two types: macronutrients,which are required in larger amounts (Eg. Potassium, phosphorus, calcium,magnesium, sulphur and iron) and micronutrients, which are required in
trace amounts (Eg. Cobalt, zinc, boron,copper, molybdenum and manganese) and are essential for enzyme action.Example, Manganese is required for activity of enzyme needed for synthesis of oligosaccharides and glycoproteins. Molybdenum is necessary for fixation of nitrogen by enzyme nitrogenase.
8.1 Water
Water is the most abundant component in living organisms. Life on earth is inevitably linked to water. Water makes up 70% of human cell and upto 95% of mass of a plant cell (Figure 8.2).
8.1.1 Chemistry of Water
Water is a tiny polar molecule and can readily pass through membranes.Two electronegative atoms of oxygen share a hydrogen bonds of two water molecule. Thus, they can stick together by cohesion and results in lattice formation (Figure 8.4).
8.1.2 Properties of Water
• Adhesion and cohesion property
• High latent heat of vaporisation
• High melting and boiling point
• Universal solvent
• Specific heat capacity
