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con = together mono = single
di = two -sacchar = sugar
glyco = sweet -poly - many
-lyse = break tri = three
macro = large
meros = part
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Polymer (poly = many, meris = part)
- long molecule consisting of many similar or identical building blocks linked by covalent bonds.
- Ex. cars linked by chains.
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Monomer (smaller molecules)
repeating units that serve as building blocks of a polymer
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Condensation reaction
Monomers are connected by condensation reaction, in which two molecules are covalently bonded to each other through loss of water molecule. More specifically called dehydration reaction.
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Dehydration Reaction a.k.a. condensation reaction
called dehydration reaction because a water molecule is lost. Each monomer contributes a water molecule that is lost ---OH and ---H, this process can be repeated as monomers make polymers. Dehydration process is sped up by enzymes which speeds up the process of chemical reaction.
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Hydrolysis (reverse of dehydration process)
- Polymers are disassembled to monomers by hydrolysis (reverse of dehydration). Process which bonds are broken by water, with ---H attaching to a monomer and ---OH (hydroxyl group) attaching to another monomer.
- Ex. of hydrolysis working in our bodies is digestion. Bulk of food is in forms of polymers, which is too big to enter our cells. Within the digestive track, enzymes attack polymers, speed up hydrolysis, then released monomers enter the bloodstream for distribution to all body cells. Those cells go through dehydration reactions to assemble monomers to polymers that can perform specific functions required by the cell.
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Carbohydrate (serve as fuel and building material)
include both sugars and polymer of sugars. Carbs also include polysaccharides, polymers consists of many sugar building blocks.
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Monosaccharide
- monosaccharides = simplest sugars. Most common: glucose consists of a carbonyl group (>C=O) and multiple hydroxyl groups (---OH). Depending on location of carbonyl group, it is either an aldose (aldehyde sugar) or a ketose (ketone sugar). Monosaccharides, particularly glucose, are major nutrients for cells.
- Ex. Glucose is an aldose (an aldehyde) & fructose, a structural isomer of glucose, is a ketose (ketone).
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Disaccharide
- Disaccharides = double sugars, 2 monosaccharides joined by a covalent bond, glycosidic linkage. Most prevalent disaccharides is sucrose, table sugar (2 monomers are fructose and glucose).
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Glycosidic Linkage
- covalent bond formed by two monosaccharides by a dehydration reaction.
- Ex. Maltose (a.k.a. malt sugar used for brewing beer) is a disaccharide formed by linking of 2 molecules of glucose (by Glycosidic Linkage)
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Polysaccharide
- polymers with a few hundred to a few thousand monosaccharide joined by glycosidic linkages.
- Some polysaccharides serve as storage material, hydrolyzed as needed to provide sugar for cells and others serve as building material for structures that protect the cell or the whole organism.
- (Architecture and function depends on its monomers and positions of its glycosidic linkages.
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Starch (storage polysaccharides)
- Plants store starch, polymer of glucose monomers, to stockpile surplus glucose.
- Starch = stored energy because glucose is a major cellular fuel.
- Sugars can be retrieved through carbohydrate bank through hydrolysis which breaks the bond of glucose monomers. Most plants and humans have enzymes to hydrolyze plant starch, making glucose available as nutrients for cells.
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Glycogen (storage polysaccharides)
- polysaccharide that animals store.
- Human and other vertebrates store glycogen mainly in liver and muscle cells.
- Hydrolysis of glycogen in these cells release glucose when the demand for sugar increases.
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Cellulose (structural polysaccharides).
Organisms build strong materials from structural polysaccharides.
- Cellulose, struc polysach, is a major component of the tough walls that enclose plant cells.
- Like starch, cellulose is a polymer of glucose but glycosidic linkage differ between two.
- Glucose form alpha and beta rings. Cellulose form beta rings and starch form alpha rings.
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Chitin (structural polysaccharide)
- carbohydrate used by arthropods (i.e. spiders, insects, crabs, etc.) to build their exoskeleton (hard case protecting soft inside) and by many fungi, which instead of cellulose, use chitin as a building material for cell walls.
- FUN FACT: pure chitin is leathery and soft, but hardens when encrusted with calcium carbonate (salt). Also used to make strong, flexible surgical thread that decomposes after the wound or incision heals.
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Lipid (not contain true polymers and not big enough to be considered macromolecules. they are grouped together because mix poorly, if at all, with water)
- Hydrophobic due to molecular structure. Maybe contain some polar bonds associated with oxygen, but it is mainly composed of hydrocarbon regions.
- Lipids vary in form and function (i.e. waxes and pigments). but FOCUS HERE on: fats, phospholipids, and steroids.
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Fat (lipids)
Major Function: is energy storage. Hydrocarbon chains are similar to gasoline molecule and just as rich in energy. A gram of fat stores twice as much energy than gram of polysaccharide. Plants are immobile so can carry bulky starch (polysaccharide) but animals move, so advantageous to have more compact fuel.
assembled by two small molecules (by dehydration reaction), glycerol and fatty acids.
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Fatty Acid
Long carbon skeleton (usually 16-18 carbon atoms), carbon at one end has a carboxyl group (hydroxyl and carbonyl group = carboxyl. O=C--OH), which the functional group that gives its name of fatty acid. This in turn is attached to a long chain of hydrocarbons, which is relatively a nonpolar C--H bonds that make fats hydrophobic.
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Triacylglycerol (fat) a.k.a. triglyceride found in most food packages.
3 fatty acids join glycerol by an ester linkage, a bond between a carboxyl group (fatty acid) and hydroxyl group (--OH of glycerol).
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Saturated Fatty Acid (fatty acid varying in length and location of double bonds)
- Fat saturated with hydrogen. Ex. Butter @ room temperature is a solid. This is due because there are NO double bonds between carbon atoms composing the chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton; HENCE, saturated with hydrogen = saturated fatty acid.
- FUN FACT: Fat made from sat. fatty acids are saturated fat i.e. most animal fats. Lard and butter are solid at room temp.
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Unsaturated Fatty Acid (fatty acid varying in length and location of double bonds)
Recent studies have shown that the process of hydrogenating vegetable oils produces not only saturated fats but also unsaturated fats with trans double bonds. These trans fats may contribute more than sarurated fats to atherosclerosis (see Chapter42) and other problems. Because trans fats are especially common in baked goods and processed foods, the USDA requires trans fatcontent
information on nutritional labels.
- has one or more double bonds formed by removal of hydrogen atoms from carbon skeleton.
- Fatty acid will have kinks in hydrocarbon chain wherever a cis double bond occurs.
- EX: fats of fish and plants are generally unsaturated (built of one or more types of unsaturated fatty acids). Usually in liquid form (@ room temp.) and are generally referred to oils (i.e. olive oil and cod liver oil)
- cis double bonds prevent molecules from packing closely together.
- FUN FACT: hydrogenated vegetable oil (on food packages) mean unsaturated fats has been synthetically converted to saturated fats by adding hydrogen. Ex. Peanut butter and margarine have been hydrogenated to prevent lipids from separating out in liquid (oil) form.
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Steroid (lipids characterized by carbon skeleton consisting of four fused rings)
Many hormones, as well as cholesterol, are steroids.
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Cholesterol
- Molecule where other steroids, including sex hormones, are synthesized. Produce steroids, including sex hormones.
- Cholesterol is crucial in animals
- Saturated fats and trans fat exert their negative impact on health by affecting cholesterol levels.
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Protein
- Some speed up chemical reactions, play a role in structural support, storage, transport, cellular communication, movement, and defense against foreign substances.
- Ex. Enzymes are proteins that act as catalysts, chemical agents that selectively speed up chemical reactions without being consumed by the chemical reaction.
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Polypeptide (protein polymers)
polymers constructed from the same set of 20 amino acids. A protein consists of one or more polypeptides.
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Amino Acid (carboxyl and amino group)
carboxyl (O=C---OH) and amino group (H2>N)
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