Introduction to Biomolecules

• Biomolecules are molecules produced by living organisms
• They include carbohydrates, lipids, nucleic acids, and proteins
• These molecules are essential for various biological processes and life

Carbohydrates

• Carbohydrates serve as a primary source of energy for living organisms
• They also play structural roles in cells and tissues
• Carbohydrates are composed of carbon, hydrogen, and oxygen atoms
• Their general formula is (CH2O)n, where n is the number of carbon atoms
• Monosaccharides are the simplest form of carbohydrates
• Examples of monosaccharides include glucose, fructose, and galactose
• Disaccharides consist of two monosaccharides joined together by a glycosidic bond
• Examples of disaccharides include sucrose (glucose + fructose) and lactose (glucose + galactose)
• Polysaccharides are complex carbohydrates made up of many monosaccharides
• Examples of polysaccharides include starch, glycogen, and cellulose
• Starch is the primary energy storage form in plants
• Glycogen is the primary energy storage form in animals
• Cellulose is a structural component of plant cell walls

Lipids

• Lipids are a diverse group of hydrophobic molecules
• They include fats, oils, phospholipids, and steroids
• Lipids serve as energy storage, structural components of cell membranes, and hormones
• Triglycerides (fats and oils) are composed of glycerol and three fatty acids
• Saturated fatty acids contain no carbon-carbon double bonds
• They are typically solid at room temperature
• Unsaturated fatty acids contain one or more carbon-carbon double bonds
• They are typically liquid at room temperature
• Phospholipids are composed of glycerol, two fatty acids, and a phosphate group
• They are major components of cell membranes, forming a lipid bilayer
• Steroids are characterized by a four-ring structure
• Examples of steroids include cholesterol, testosterone, and estrogen
• Cholesterol is a precursor for many steroid hormones and a component of cell membranes

Nucleic Acids

• Nucleic acids store and transmit genetic information
• There are two main types of nucleic acids: DNA and RNA
• DNA (deoxyribonucleic acid) contains the genetic instructions for all living organisms
• RNA (ribonucleic acid) is involved in protein synthesis and gene regulation
• Nucleic acids are polymers of nucleotides
• Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base
• The sugar in DNA is deoxyribose, while the sugar in RNA is ribose
• The nitrogenous bases in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T)
• The nitrogenous bases in RNA are adenine (A), guanine (G), cytosine (C), and uracil (U)
• DNA is a double-stranded helix, with two strands held together by hydrogen bonds between complementary bases
• A pairs with T, and G pairs with C
• RNA is typically single-stranded, although it can fold into complex structures
• Messenger RNA (mRNA) carries genetic information from DNA to ribosomes
• Transfer RNA (tRNA) carries amino acids to ribosomes during protein synthesis
• Ribosomal RNA (rRNA) is a component of ribosomes

Proteins

• Proteins are involved in virtually all biological processes
• They serve as enzymes, structural components, transport molecules, and hormones
• Proteins are polymers of amino acids
• There are 20 different amino acids commonly found in proteins
• Amino acids are joined together by peptide bonds
• A polypeptide is a chain of amino acids
• The primary structure of a protein is the sequence of amino acids
• The secondary structure refers to local folding patterns, such as alpha helices and beta sheets
• The tertiary structure is the overall three-dimensional shape of a protein
• The quaternary structure refers to the arrangement of multiple polypeptide chains in a protein complex
• Enzymes are proteins that catalyze biochemical reactions
• They bind to substrates and lower the activation energy of reactions
• Antibodies are proteins that recognize and bind to foreign substances, such as bacteria and viruses
• Transport proteins carry molecules across cell membranes or in the bloodstream
• Hormones are signaling molecules that regulate various physiological processes