8/26 Parts of CH3 and 4: Review of Bio 241/242 Please also review the cell structure power point for cell structure review materials which are also important. Peptides: bonds and structure Nucleosides: ATP, GTP, DNA Carbohydrate classes: mono, di and poly Lipids: Fatty acid, triglyceride, phospholipid, cholesterol For Wednesdays quiz (20 pt total) be able to draw/recognize the 20 amino aicds, fatty acids (saturated or unsaturated), triglycerides, a phospholipid, and cholesterol. Be able to recognize a nucleoside (i.e. ATP) and the structural features of a carbohydrate. Also be able to compare their relative water solubility (VIP). If it is in the notes up to the end of this lecture it is good material for the quiz. 4 points of the quiz will review the others parts of the notes to this point.

Not all books write things in the same way, not all experts agree Not all books write things in the same way, not all experts agree. Welcome to life as a cell biologist. Here is how two Biochemistry books depict the formation of a peptide bond (Lehninger 1998, as well as Murray 2003 show it like this). Our book shows it as a –NH3+ added to a –COO- -> H2O + peptide bond

What does a peptide bond look like spatially What does a peptide bond look like spatially? This is called a “condensation” reaction because water is formed Becker_6e_IRCD_Chapter_3

Bonds and Interactions between R-groups of the peptide backbone Directly Determine Protein Folding and Stability. Becker_6e_IRCD_Chapter_3

Figure 3-6 The Four Levels of Organization of Protein Structure Becker_6e_IRCD_Chapter_3

Disulfides between adjacent cysteines determine the Primary Structure of the two chains that make up your Insulin. Becker_6e_IRCD_Chapter_3

The Four Levels of Organization of Protein Structure Becker_6e_IRCD_Chapter_3

Nucleotide consist of a ribose (3’ OH-sugar), base (A,T, G,C, or U) and a triphosphate. Link the phosphate to ribose with a phosphoester bond (cut off two phosphates) and you have RNA or DNA. Becker_6e_IRCD_Chapter_3

Nucleotide  remove sugars Nucleoside Becker_6e_IRCD_Chapter_3

Hydrogen Bonds between two antiparallel nucleotide chains creates the base pairs that stabilize your DNA (that’s why RNA is unstable) Becker_6e_IRCD_Chapter_3

Structures of Monosaccharides: ONE sugar sized units Structures of Monosaccharides: ONE sugar sized units. Carbohydrates contain a keto- or aldehydre group and many hydrocarbon groups Becker_6e_IRCD_Chapter_3

The Structure of D-Glucose: it is most stable as a ring Note: Aldol + hydrocarbons = carbohydrate Becker_6e_IRCD_Chapter_3

There are three main types of “Disaccharide” Two monosaccharides held together by a single glycosidic bond! Cells mostly absorb only monosaccharides, enzymes need cut linkage! “Polysaccharides” Consists of long chains of sugar units linked by glycosidic bonds Provides structural support to cells and/or organisms Structure: Mostly unbranched Sometimes water insoluble (two special types are branched) Types: Cellulose-plants Chitin-insects and crabs Cell wall- bacteria Important fact: VERY Indestructible! Becker_6e_IRCD_Chapter_3

The Structure of Starch (plant) and Glycogen (animal) These are used to STORE sugars for later use. These are water insoluble (precipitate) as white crystals inside cells. Becker_6e_IRCD_Chapter_3

Two types of “BRANCHED” polysaccharide store energy for later use Starch = plant only Glycogen = animal only Cellulose in plants is for structure and is “UN”branched Becker_6e_IRCD_Chapter_3

Seven Major Classes of Lipid (non polar) 1)Fatty Acids: used for energy and movement into/out of cells 2)Triglycerides: used for energy storage you know where 3)Phospholipids: strongly amphipathicplasma membrane possible -CH=CH- give lipid a “kink” (V.I.P.) Becker_6e_IRCD_Chapter_3

We All Need Steroids! Try to be able to recognize the steroid structure (3-6 carbon rings + one 5-carbon rings) Remember : Cholesterol is only made by mammals and cholesterol is the base that is used to create the more complicated and specific hormones below. Two Lipid Classes Not Shown Glycolipids like sphingomyelin Terpenes like vitamin A Becker_6e_IRCD_Chapter_3