Biomolecules

• Living organisms are made of the same chemicals (elements and compounds) as non-living matter like the earth's crust
• Relative abundance of carbon and hydrogen is higher in living organisms compared to the earth's crust
• Chemical analysis of living tissues involves grinding in trichloroacetic acid to obtain acid-soluble and acid-insoluble fractions
• Thousands of organic compounds are found in the acid-soluble pool of living tissues
• Living tissues contain inorganic elements and compounds, which are revealed through a destructive experiment involving burning and analyzing the remaining 'ash'
• Elemental analysis gives the elemental composition of living tissues like hydrogen, oxygen, chlorine, and carbon
• Amino acids are organic compounds found in living tissues, containing an amino group and an acidic group on the same carbon
• Proteins are made up of twenty different proteinaceous amino acids with varying R groups
• Amino acids can be classified as acidic, basic, neutral, or aromatic based on their functional groups
• Lipids in living tissues are generally water-insoluble and can be simple fatty acids or more complex structures like phospholipids found in cell membranes
• Lipids can be saturated or unsaturated fatty acids, and can also include glycerol esterified with fatty acids
• Living organisms contain nitrogen bases like adenine, guanine, cytosine, uracil, and thymine, which are part of nucleosides and nucleotides
• Nucleic acids like DNA and RNA consist of nucleotides and function as genetic material
• Primary metabolites in living organisms include amino acids, sugars, etc., while secondary metabolites in plants, fungi, and microbes include alkaloids, flavonoids, essential oils, antibiotics, and pigments
• Biomolecules in living organisms are classified as micromolecules (molecular weight less than 1000 daltons) and macromolecules (molecular weight above 10000 daltons), with proteins, nucleic acids, polysaccharides, and lipids being macromolecules
• Lipids, although small molecular weight compounds, are considered macromolecules due to their arrangement in structures like cell membranes
• The chemical composition of living tissues includes water as the most abundant component, followed by proteins, nucleic acids, carbohydrates, lipids, and ions
• Water is the most abundant chemical in living organisms
• Proteins are polypeptides, linear chains of amino acids linked by peptide bonds
• A protein is a heteropolymer, not a homopolymer, as it consists of 20 types of amino acids
• Certain amino acids are essential for health and must be supplied through diet
• Dietary proteins are the source of essential amino acids
• Proteins carry out various functions in living organisms, such as transporting nutrients, fighting infectious agents, acting as hormones, and functioning as enzymes
• Collagen is the most abundant protein in the animal world
• Ribulose bisphosphate Carboxylase-Oxygenase (RuBisCO) is the most abundant protein in the biosphere
• Polysaccharides are long chains of sugars, with cellulose being a homopolymer consisting of glucose
• Starch is a variant of cellulose found as an energy store in plant tissues, while animals have glycogen
• Inulin is a polymer of fructose
• Nucleic acids are polynucleotides, with DNA containing deoxyribose and RNA containing ribose
• Proteins have a primary structure (sequence of amino acids), secondary structure (folded helix), tertiary structure (folded upon itself), and quaternary structure (assembly of multiple polypeptides or subunits)
• Enzymes are proteins that catalyze reactions, with an active site where substrates bind and react to form products
• Enzymes catalyze reactions at high rates, with thermal stability being important for enzyme function
• Enzymes can accelerate reaction rates significantly, with thousands of types of enzymes each catalyzing unique chemical or metabolic reactions
• Enzymes can form metabolic pathways, where multiple enzyme-catalyzed reactions lead to the conversion of substrates into products
• Enzymes bring about high rates of chemical conversions by binding substrates at their active sites and forming enzyme-substrate complexes
• Enzyme action involves the formation of an 'ES' complex, where E stands for enzyme, and it is a transient phenomenon
• During the state where the substrate is bound to the enzyme active site, a transition state structure of the substrate is formed
• After bond breaking/making is completed, the product is released from the active site, transforming the structure of the substrate into the structure of the product(s)
• The pathway of transformation must go through the transition state structure, with many unstable intermediate structural states
• Each enzyme has a substrate binding site, forming a highly reactive enzyme-substrate complex (ES) that dissociates into product(s) P and the unchanged enzyme