Biomolecules

• Carbohydrates


  Organic compounds that serve as the main source of energy in all organisms. Together with proteins, carbohydrates also function as structural components of living cells. Carbohydrates are made up of carbon, hydrogen and oxygen molecules where the proportion of hydrogen to carbon and oxygen atoms is two is to one. {Cn(H2O)n}
• Main groups of carbohydrates

  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides


  Simple sugars with only one sugar unit. Identified based on the number of carbon atoms they are made of. Triose (3 carbon atoms), Pentose (5 carbon atoms), Hexose (6 carbon atoms). Examples: glucose, fructose, galactose, mannose.
• Monosaccharides


  • Highly soluble in water and can easily pass through membranes
  • Glucose is an indispensable component of the mammalian blood and is found, at least in small quantities, in all animals
  • Fructose is commonly found in plants but is rarely found in animals
  • Ribose and deoxyribose form the backbones of RNA and DNA respectively
• Disaccharides


  Complex sugars made up of two molecules of monosaccharides chemically joined together. Chemical formula: C12H22O11. Examples: sucrose, maltose, lactose.
• Formation of disaccharides


  1. Condensation or dehydration synthesis (two monosaccharides joined together with loss of water molecule)

  2. Hydrolysis or hydrolytic reaction (water molecule added to split disaccharide into monosaccharides)
• Disaccharides have different degrees of sweetness
• Lipids


  Organic substances that include fats and fat-like substances such as phospholipids, waxes, steroids, and others
• Lipids


  • Generally hydrophobic substances and are insoluble in water
  • Made up of carbon, hydrogen and oxygen but they contain less oxygen in proportion to hydrogen
  • Have the "job" of storing energy for later use
  • Found in hormones and cell membrane components
• Functions of lipids in living organisms

  • Source and storage of energy
  • Essential part of cell structures such as cell membranes
  • Insulating material to prevent heat loss and protection against extreme cold
  • Solvent for fat-soluble vitamins and hormones
  • Prevents water loss from skin surface
• Fats


  Lipids composed of 1 molecule of glycerol (an alcohol containing 3 carbons) and 3 fatty acid molecules
• Fatty acids


  Two types - saturated and unsaturated
• Saturated fatty acids


  • Solid at room temperature
  • Mostly found in animals
  • Examples: Lard, margarine and butter
• Unsaturated fatty acids


  • Occur in liquid state at room temperature
  • Found most in plants
  • Examples: Vegetable oil and corn oil
  • Believed to be healthier sources of fats compared to saturated forms
• Polysaccharides


  Complex sugars made up of chains and/or branches of monosaccharides formed by condensation reactions. Basic formula: ((C6H10O5)n, where n refers to the number of monosaccharides present.
• Phospholipids


  • Important components of cell membranes
  • Made up of 2 fatty acid molecules and 1 phosphate group
  • Fatty acid components are hydrophobic while the phosphate group is hydrophilic
  • Responsible for the polar and non-polar characteristic of cell membranes
• Waxes


  Lipids which are important components for many organisms, such as the cuticle covering the surfaces of leaves and stems of plants and protective coverings on the skin and fur of some animals
• Steroids


  • Lipids with a carbon skeleton of 4 fused rings
  • Examples: Cholesterol, bile salts, sex hormones and vitamin D
  • Cholesterol adds strength to the plasma membrane of animal cells and serves as a precursor of in the formation of other steroids
• Triglycerides


  • Also known as blood fats, circulate in our blood stream along with cholesterol
  • We get triglycerides from the food such as meat and plant oil as well as our body makes its own
  • We need just the right amount of triglycerides because too much of it can increase our risk of heart and blood vessel diseases
• Polysaccharides


  • Can act as storage (starch, glycogen) or structural (cellulose, chitin) molecules
  • Starch is a plant storage carbohydrate composed of glucose molecules, easily digested by animals
  • Cellulose is the most abundant organic compound on earth, found in plant cell walls, indigestible by humans and many animals
  • Glycogen is an animal starch, stored in liver and muscles as a readily available glucose reserve
  • Chitin is a structural polysaccharide found in the outer coverings of crustaceans and insects, highly rigid and insoluble
• Nucleic acids


  Organic compounds that function for the storage of genetic information which is transmitted from one generation to the next in all living organisms
• One gram of burned carbohydrates releases 4 kilocalories (kcal) of energy
• Nucleic acids


  • They are the physical carrier of inheritance that is passed from parents to offspring
  • They function in protein synthesis as they carry the code needed in the formation of specific proteins
• Functions of carbohydrates


  • Must be converted to glucose and other simple sugars to be utilized by the body
  • Simple sugars burn quickly, providing instant burst of energy
  • Starch burns more slowly, providing longer-lasting, more stable energy source
  • Combine with proteins (glycoproteins) and lipids (glycolipids) to form molecules needed for bodily functions
  • Sugar ribose is a component of DNA and RNA
• Proteins


  The most abundant organic compounds found in any living organisms, responsible for as much as 15% of the body's dry weight
• A typical mammalian cell may contain as much as 10,000 different kinds of proteins having a diverse array of functions
• Proteins


  • Form the structural parts of cells and tissues such as the keratin in hairs, collagen in connective tissues, myosin and actin in muscle cells
  • Enzymes that accelerate chemical reactions
  • Antibodies responsible for the body's defense against infection
  • Hormones that regulate body functions
  • Growth factors that influence an organism's growth and development
  • Gene activators, membrane receptors, transporters, contractile elements, blood clots, toxins, etc.
  • Carry out virtually all the activities inside the cell
• Amino acids


  The basic building blocks of proteins
• There are 20 essential amino acids in living organisms that serve as building blocks in the formation of different proteins
• Amino acid


  Made up of amino group (NH2), a carboxyl group (COOH) and a hydrocarbon side chain referred to as the R group

  
• Types of nucleic acids

  • Deoxyribonucleic acid (DNA)
  • Ribonucleic acid (RNA)

  
• Types of amino acids

  • Essential
  • Nonessential
• Essential amino acids


  Not synthesized by the body but obtained from food
• Nonessential amino acids


  Naturally produced in the body
• Complete or high quality proteins


  Contain all essential amino acids in the ratio needed by the body, derived from animal sources
• Incomplete or low-quality proteins


  Deficient in one or more of the essential amino acids, obtained from plants
• Nucleotide


  The basic building block of nucleic acids, made up of a 5-carbon sugar, a phosphate group and a nitrogenous base

  
• Nitrogenous bases


  • Purines (guanine {G}, adenine {A})
  • Pyrimidines (cytosine {C}, thymine {T}, uracil {U})

  
• Ribose


  The sugar most commonly found in RNA
• Deoxyribose


  The sugar most commonly found in DNA, "deoxy" means lack or absence of oxygen