Biological Chemistry

Macromolecules Large organic molecules Basic Structure POLYMERIZATION!

Macromolecules Carbohydrates Lipids Proteins Nucleic Acids

Carbohydrates

Carbohydrates Monomers are called monosaccharides Primarily made of carbon, hydrogen, and oxygen Only ratio: 1 C: 2 H: 1 O C6H12O6 Note the shape or kind of ring that glucose has… we call this a hexose. Sugars that have a 5-sided carbon ring is a pentose, so on and so forth.

Monosaccharides Glucose 3 isomers Notice the shape of each monosaccharide example Hexagon shape = hexose Pentagon = pentose Notice the slight differences of glucose and galactose. Their differences can be seen on C-4 and C-5.

6 5 4 1 There are also variable of each monosaccharide. When distinguishing between an alpha or beta glucose, we look at the position of the hydroxyl group of Carbon-1. The carbons are numbered as shown in the slide. 2 3

Bond strength within the polymer can be determined which type of monosaccharide is being used; as you will later see with polysaccharides

Disaccharides (dimer) Formed by a condensation reaction between two monosaccharides Condensation or dehydration reaction  water is lost in the process Opposite of a condensation reaction is hydrolysis (meaning: splitting of water)

Disaccharides (dimer) Maltose = glucose + glucose malt sugar Syrup Alpha & Beta glucose

Disaccharides (dimer) Sucrose = glucose + fructose table sugar 1 2 syrup

Disaccharides (dimer) Lactose = glucose + galactose milk sugar syrup

Polysaccharides Long chains of monosaccharides

Polysaccharides Cellulose: long, unbranched structural material in plants  wood! Cannot be digested by humans, but important in “regularity” by stimulating mucus production in intestines  Glycosidic bonds occur between many beta-glucose  very strong  therefore, structural material! Humans cannot break glycosidic bonds between beta-glucose, so we cannot break it down and use its glucose. However, it provides bulk (or ruffage; fiber) to help our digestive system move things along. This happens because cellulose stimulates mucus production in our intestines… helping to create lubrication for our feces. 

Polysaccharides Starch may be branched Food storage in plants Think of potatoes, rice, etc. Picture: amylopectin Bonds occur between alpha-glucose

Polysaccharides Glycogen similar to starch, but HIGHLY branched Food storage in animals Bonds occur between alpha-glucose

Polysaccharides

Lipids

Lipids Nonpolar Examples Vital components in cell membranes Oils Cholesterol Fats Vital components in cell membranes Can form waterproof coatings on leaves, wool, and feathers There are no monomers of lipids… well, sort of.  Some lipid molecules combine to form larger ones, but do not, technically, qualify as polymers.

Fatty Acids Long hydrocarbon chain with a carboxyl group at one end Charged end is hydrophilic Nonpolar end is hydrophobic

“micelle” Detergents work this way. They have a polar group that interacts with water and a hydrocarbon chain that interacts with lipids (in this case, it’s oil) Most important in biological systems is BILE! It separates the fat into smaller components so that lipase can break up the fats into its “monomers”

Fatty Acids Saturated Fat (solid @ room temp) Full of hydrogen No double bonds within hydrocarbon chain Symmetric can pack more of these in a smaller area (bad fat!) Butter, lard, shortening

Fatty Acids Saturated Fat (solid @ room temp) Too much of this type can increase risk of heart disease

Fatty Acids Unsaturated Fat (liquid @ room temp) Not full of hydrogen Double bonds  kinks “good” fats oils

Triglycerides (Fats) 3 fatty acids +glycerol Formed by condensation 3 H2O molecules can form from the formation of a fat molecule.

Phospholipids Structural molecules  contribute to shape of cell Does not always have to be choline; variable polar group

Steroids 4 ring structure Make up hormones Testosterone Progesterone Cholesterol Structure shown: aldosterone

Bile