Biochemistry of Lipids and Carbohydrates

Biomolecules

• Biomolecules are organic compounds found in living organisms
• They are essential for life processes
• The four major classes of biomolecules are carbohydrates, lipids, proteins, and nucleic acids

Carbohydrates

• Organic compounds consisting of carbon, hydrogen, and oxygen
• Known chemically as polyhydroxy aldehydes or ketones
• Simple carbohydrates have one or two sugar molecules, while complex ones have three or more
• Common examples include glucose, sucrose, cellulose, and starch
• General formula: Cx(H₂O)y

Monosaccharides

• Simple sugars
• Cannot be hydrolyzed into smaller units
• Contain an aldehyde or ketone group
• Examples include glucose, fructose, and galactose

Disaccharides

• Carbohydrates made up of two monosaccharides
• Linked together by a glycosidic bond
• Can be hydrolyzed into their constituent monosaccharides
• Common examples are sucrose, maltose, and lactose

Polysaccharides

• Large carbohydrate molecules composed of multiple monosaccharides
• Used for energy storage or structural support
• Examples include cellulose and starch
• Can be homopolysaccharides (identical monosaccharides) or heteropolysaccharides (different monosaccharides)
• Can be linear or branched

Carbohydrate Properties

• Solubility: The number and arrangement of hydroxyl groups determine solubility in water, crucial for transport
• Reducing Properties: Act as reducing agents in biological processes due to their ability to donate electrons
• Optical Activity: Possess optical activity due to chiral carbon atoms, existing as enantiomers
• Isomerism: Molecules with the same chemical formula but different structures or spatial configurations.

Carbohydrates in Biotechnology

• Early Biotechnology: Fermentation processes used microorganisms to produce cheese, yogurt, bread, and alcoholic beverages. Domestication of crops for food.
• Modern Biotechnology: Enzyme production using microorganisms, carbohydrate-based biopolymers for tissue engineering, smart hydrogels for responding to environmental stimuli, and carbs-based therapeutics

Lipids

• Macromolecules composed of fatty acids and their derivatives
• Insoluble in water but soluble in organic solvents
• Examples include fats, oils, hormones, and certain membrane components
• Grouped together due to hydrophobic interactions
• Essential constituents of a diet in the human body

Lipid Properties

• Nonpolar Nature: Oily, nonpolar molecules stored in adipose tissue
• Diverse Compounds: A diverse group of compounds primarily composed of hydrocarbon chains
• Energy Source: Energy-dense organic molecules crucial for various life processes
• Insolubility: Characterized by insolubility in water
• Structural Role: Fundamental structural components, creating barriers like cell membranes

Types of Simple Lipids

• Fats: Esters of fatty acids containing glycerol. Liquid fats are oils.
• Waxes: Esters of fatty acids and high-molecular weight monohydric alcohols.

Types of Complex Lipids

• Phospholipids: Composed of fatty acids, alcohol, a phosphate group, and nitrogen-containing bases and other substituents
• Glycolipids: Composed of a fatty acid, sphingosine, and a carbohydrate component

Types of Fatty Acids

• Saturated: Absence of carbon-carbon double bonds
• Unsaturated: Presence of one or more carbon-carbon double bonds

Types of Precursor and Derived Lipids

• Unsaturated fatty acids
• Cholesterol: Wax-like substance, found in animal sources. Combination of steroids and alcohol.

Lipid Functions

• Energy storage
• Insulation and protection
• Regulation and signaling
• High-energy source

Lipids in Biotechnology

• Early Biotechnology: Soap production via saponification. Fuel for lamps and candles
• Modern Biotechnology: Biofuels derived from algae and other sources. Nutraceuticals and cosmetics using plant-based and biotechnologically sourced lipids.

Proteins

• Naturally-occurring unbranched polymers of amino acids
• Most abundant molecules in cells after water
• Account for about 15% of a cell's overall mass

Amino Acids

• Organic compounds with an amino group (-NH₂) and carboxyl group (-COOH) attached to the same carbon atom (alpha-carbon)
• Differ by their R-groups (side chains)
• Classified as nonpolar, polar, polar acidic, or polar basic

Essential vs. Nonessential Amino Acids

• Essential: Must be obtained from the diet
• Nonessential: The body can synthesize them

Protein Structure

• Primary: The sequence of amino acids in a polypeptide chain
• Secondary: Alpha-helices and beta-sheets formed by hydrogen bonds
• Tertiary: The 3D shape of a polypeptide formed by various bonds(covalent and noncovalent)
• Quaternary: Multiple polypeptides forming a functional protein, held together by bonds

Protein Classifications

• Based on functions: Catalytic, defense, transport, messenger, contractile, structural, transmembrane.

Proteins in Biotechnology

• Early Biotechnology: Identification of albumin and gluten, important proteins
• Modern Biotechnology: Pharmaceuticals (treating diseases via targeting specific proteins), recombinant antigens, and biodegradable plastics from specific protein combinations(e.g. PHA)

Nucleic Acids

• Complex macromolecules essential for storing and transmitting genetic information in all living organisms
• Initially discovered within the cell nuclei
• Consist of carbon, hydrogen, oxygen, nitrogen, and phosphorus

Types of Nucleic Acids

• DNA (deoxyribonucleic acid): An organism's genetic blueprint. Composed of four nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G). Double helix structure
• RNA (ribonucleic acid): Plays a key role in translating genetic information from DNA into proteins, including messenger, transfer, and ribosomal RNAs. Contains uracil (U) instead of thymine. Usually single-stranded

Nucleic Acid Structure

• Nucleotides: Monomer units of nucleic acids.
• Each nucleotide has a sugar, a nitrogenous base, and a phosphate group
• DNA typically forms a double helix, RNA single-stranded.

Nucleic Acid Functions

• DNA: Stores genetic information, transmits information across generations and replicates
• RNA: Translates the genetic information into instructions for protein synthesis, involved in protein synthesis

Nucleic Acids in Biotechnology

• Early Discoveries: Structure of DNA, DNA synthesis, mRNA. Technologies for manipulating genetic information
• Modern Biotechnology: Gene Editing (CRISPR-Cas9), synthetic biology, diagnostic tools (PCR), therapeutics (mRNA vaccines), personalized medicine, and environmental monitoring

Biomolecules in Early and Modern Biotechnology

• Various applications in early and modern biotechnology