Campb ell et al., Chapter 4 and beginning of Chapter 5

ORGANIC CHEMISTRY is the chemistry of carbon (C) which makes 4 bonds.
In "Star Trek" (the first movie), people were called "carbon based units" by the alien.

Hydrocarbon (Hydro-carbon - prefix suggests hydrogen, suffix suggests carbon).
They are hydrophobic and nonpolar.
CH4 methane, TRANSPARENCY (Fig. 4.2) - natural gas
Gasoline has typically 8 carbons (octane) and is fluid. Long chains are thick, like oil and vasoline.
nonpolar, hydrophobic

Carbohydrate (Carbo-hydrate is also sort of a compound word, carbon, but note that "hydrate" suggests water, not hydrogen) - the general formula is Cn(H2O)n
Monosaccharides TRANSPARENCY (Fig. 5.3)
Hexose (hex = 6 [carbons], "-ose" always means sugar)- glucose, the most famous monosaccaccharide, is good to illustrate that monosaccharides usually assume a ring structure TRANSPARENCY (Fig. 5.4)
Pentose - ribose, deoxyribose (that are in RNA and DNA) are famous
Compound dehydration synthesis, hydrolysis (hydro-water, lysis-breakdown) TRANSPARENCY (Fig. 5.2)
In digestion, macromolecules are broken down to monomers.
Disaccharide - sucrose, lactose (milk) TRANSPARENCY (Fig. 5.5) shows maltose and sucrose, and shows dehydration synthesis.
Polysaccharides starch (plant), glycogen (glyco-sugar, gen-give birth to) (animal)
alpha 1-4 linkage TRANSPARENCY (Fig. 5.7)
Carbohydrates are used for energy.
Carbohydrates are used for structure: cellulose (beta-1,4 glucoses), the most plentiful biological molecule on Earth,
Carbohydrates are used for bulk since people cannot digest fiber, but termites & cattle can. This introduces the topic of symbiosis (living together) and mutualism (where it is to the benefit of both organisms since, for termites, zooflagellates, which are protozoa, break down cellulose and for cattle, bacteria do the job.
Carbohydrates are used for structure in some proteins
Carbohydrates contribute to exoskeleton in arthropods, a polymer called chitin that has some nitrogen and is also in cell walls of fungi

Lipids (fats) store more energy (2x sugar) 1 tablespoon of sugar is 50, fat 100 "Calories" = kilocaloriies
Glycerol & 3 fatty acids (16-24 C long) - triglyceride ester bonds TRANSPARENCY (Fig. 5.10), note the dehydration synthesis
The -COOH defines an organic acid such as a fatty acid, otherwise the molecule is a hydrocarbon.
C-C (single bond) vs. C=C (double bond) unsaturated (vs saturated with H's), with several, it is referred to as "polyunsaturated" PUFA = polyunsaturated fatty acid
Animal fats tend to be saturated, bad for arteries leads to atherosclerosis; vs vegetable fats better.
Polar phospholipids -TRANSPARENCY Fig 5.13 - contribute to membranes because polar group is hydrophilic and fatty acid (acyl) tail is hydrophobic
TRANSPARENCY (Fig. 5-12) polar-glycerol-FA1-FA2 (more double bonds, fluidity)
Here are some famous fatty acids: stearic C18, Oleic-18:1, TRANSPARENCY (Fig. 5.11)
There are also glycolipids with sugar attached to lipid in membranes.
Steroids-cholesterol TRANSPARENCY (Fig. 5.14)- fit into membranes and serve as precursors for hormones,
especially "sex hormones" like testosterone, progesterone, estrogen TRANSPARENCY (Fig. 4.8)
Howard Cossel "anabolic steroids" (metabolic: catabolic vs anabolic) - androgens, the hormones like testosterone that favor nitrogen retention (muscle growth)
Salts of cholesterol are in bile (from liver) that acts like a detergent to emulsify fats to aid in digestion.
Interestingly, cholesterol is required in animals and is an "essential" nutrient in insects that cannot synthesize it; too much bad in people, and that can be controlled by diet though people also biosynthesize cholesterol.
Waxes: fatty acid + long chain alcohol (instead of glycerol) prevent water loss also used for structure in nbee hive.Blubber, especially in warm blooded cetaceans, serves as insulation.
In summary, lipids are used for energy, structure, hormones (including second messengers, see Chapter 11), insulation, water loss, digestion


This page was last updated 6/11/02

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