Exam 1 Review:  Chapter 2 - Carbohydrates and Lipids

macromolecule - Any very large molecule (more than one hundred atoms bound together at a minimum), e.g., a polymer, consisting of many smaller structural units linked together.  [Examples include carbohydrates, proteins, nucleic acids, but few lipids.]

monomer - The relatively small molecular subunit which join (form covalent bonds) with similar units to form a polymer.

polymer - Any of the numerous natural and synthetic compounds, usually of high molecular weight, which consist of up to millions of repeated, covalently linked units; each subunit (monomer) is a relatively small, simple molecule.

carbohydrate = polysaccharide - One of the groups of biologically important organic polymers which includes starches, celluloses, chitin and gums; they are constructed from simple sugars = monosaccharides as subunits; they contain primarily carbon, hydrogen, and oxygen, usually in the ratio 1:2:1 [represented by the shorthand formula: (CH₂O)_N]; some function as storage forms for nutritional energy, others function as structural components of cells and tissues.

sugar = monosaccharide - Any of several carbohydrate subunits (monomers), such as trioses (3 carbons), tetroses (4 carbons), pentoses (5 carbons), and hexoses (6 carbons), which cannot be broken down to simpler sugars by hydrolysis; most are sweet tasting; all are crystalline, water soluble, and can be catabolized to produce useful chemical energy by oxidation and fermentation reactions.  aka - simple sugar.

glucose - A crystalline monosaccharide, a hexose sugar, C₆H₁₂O₆, occurring widely in most plant and animal tissues; it is the principal circulating sugar in the blood and the major physiological energy source of the body; its blood levels are regulated by insulin, glucagon, and certain other hormones; it is the monomer for starch, glycogen and cellulose synthesis.  aka - dextrose in the food industry.

sucrose - A crystalline disaccharide of fructose and glucose, C₁₂H₂₂O₁₁, found in many plants but extracted as ordinary ("table") sugar mainly from sugar cane and sugar beets' it is widely used as a sweetener or preservative and in the manufacture of plastics and soaps; it is perceived to be the most sweet tasting of the common mono- and disaccharides found in foods.

lactose - A crystalline disaccharide of glucose and galactose, C₁₂H₂₂O₁₁, found in milk; it has a slightly sweet taste and is much less soluble in water than either sucrose or glucose.  aka - milk sugar.

ribose - A crystalline monosaccharide, a pentose sugar, C₅H₁₀O₅, occurring as a component of the vitamin riboflavin, and a monomer of nucleotides and ribonucleic acids (RNA).

deoxyribose - A crystalline monosaccharide, a pentose sugar, C₅H₁₀O₄ (containing one less oxygen than ribose), occurring as a monomer of nucleotides and deoxyribonucleic acids (DNA).

starch - A branching carbohydrate polymer [represented by the shorthand formula: (CH₂O)_N] composed of many repeating units of glucose, C₆H₁₂O₆; this polymer of glucose serves to store energy in plants and is a major dietary nutrient for the human body; it is digested by salivary and pancreatic amylases in the digestive system.

glycogen - A branching carbohydrate polymer [represented by the shorthand formula: (CH₂O)_N] composed of many repeating units of glucose, C₆H₁₂O₆; this water-soluble compound serves to store glucose in the liver and muscle tissue and elsewhere as a nutrient for future use by the body; its metabolism in the body is regulated by hormones, insulin and glucagon in particular, and also by other insulin antagonists.

cellulose - An unbranching carbohydrate polymer composed of many repeating units of glucose ((C₆H₁₀O₅)_N) which are linked in a different configuration than in starch; this strong insoluble compound serves as the main structural component of the cell wall in most plants, and is important in the manufacture of numerous products, such as paper, textiles, pharmaceuticals, and explosives; it cannot be digested by animals but serves as "roughage" = dieatary fiber which contributes to the proper flow of digested foods through the intestines.

lipid - Any of a heterogeneous group of organic compounds, formed primarily from carbon and hydrogen with relatively few oxygens, all linked by nonpolar covalent bonds; examples include the fats, oils, waxes, sterols, triglycerides, cholesterol, cerebrosides, and phospholipids; these compounds are insoluble in water but soluble in nonpolar organic solvents; they are oily or waxy to the touch; certain of them are important biological signal molecules, e.g., steroid hormones and prostaglandin and leukotriene local hormones; together with carbohydrates are the major energy storage compounds in the body; and, together with carbohydrates and proteins, constitute the principal structural material of living cells.

amphipathic - An adjective describing any molecule which has both hydrophobic and hydrophilic regions; it applies to both large and small molecules, such as the proteins and lipids, respectively, which are found within cell membranes; most soaps, detergents and surfactants are also amphipathic.

hydrophilic - Any molecules with polar covalent bonds giving the molecules an affinity for water; so that they are readily absorbed or dissolved in water.

hydrophobic - Any molecules with few or no polar covalent bonds giving the molecules an little affinity for water; so that they are poorly or not at all absorbed or dissolved in water; such compounds do dissolve in non-polar (lipid) organic solvents such as alcohols, ethers, etc.

lipoproteins - Any of the series of soluble lipid-protein complexes which are transported in the blood; each aggregate particle consists of a spherical hydrophobic core containing triglycerides and cholesterol esters surrounded by an amphipathic monolayer of phospholipids, cholesterol and apolipoproteins; classes of lipoproteins include chylomicrons, very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL).

triglyceride - A common biological lipid, occurring as the ester of three fatty acids and glycerol, which is the chief constituent of natural fats and oils; this group of lipids is an important energy source forming much of the fat stored by the body; elevated blood levels are correlated with the development of cardiovascular disease. aka - neutral fats.

steroid - The general term for lipids derived from cholesterol including a variety of hormones:  sex hormones = gonadocorticoids (estrogens, progesterone, androgens); glucocorticoids (cortisol, cortisone, hydrocortisone, etc.) which regulate glucose metabolism and have anti-inflammatory effects; and mineralocorticoids (aldosterone) which regulate plasma water and electrolyte levels.

cholesterol - A multiple (4-membered) carbon-ring lipid molecule which serves as a minor structural component in cell membranes and is also the precursor for synthesis of estrogen, testosterone, and related steroid hormones; elevated blood levels are correlated with the development of cardiovascular disease.

phospholipid  - Any of the amphipathic molecules found in cellular membranes which consist of a glycerol residue, two non-polar fatty acid side chains and a third polar side chain which contains a phosphate ion among other polar molecular components.

List:

 6. two examples of major functions for carbohydrate molecules.

          (1) structural components of cells and intercellular materials
          (2) energy storage compounds

 7. three examples of major functions for lipid molecules.

          (1) structural components of cellular membranes
          (2) energy storage compounds
          (3) regulatory molecules = signal compounds