8/29Parts of CH3 and 4: A Quick Review of what

you ought to review from Bio 241/242

Please also review the cell structure power point for cell structure review materials which are also important.Peptides: bonds and structureNucleosides: ATP, GTP, DNACarbohydrate classes: mono, di and polyLipids: 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. 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). You can ask Dr J Hardin. Our book shows it as a –NH3+ added to a –COO- -> H2O _ peptide bond

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

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Bonds and Interactions between R-groups of the peptide backboneDirectly Determine Protein Folding and Stability.

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

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

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The Four Levels of Organization of Protein Structure

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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.

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Nucleotide remove sugars Nucleoside

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

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

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

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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 bondsProvides structural support to cells and/or organisms

Structure:Mostly unbranchedSometimes water insoluble(two special types are branched)

Types:Cellulose-plantsChitin-insects and crabsCell wall- bacteria

Important fact:VERY Indestructible!

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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.

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Two types of “BRANCHED” polysaccharide store energy for later useStarch = plant only Glycogen = animal onlyCellulose in plants is for structure and is “UN”branched

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Seven Major Classes of Lipid (non polar)1)Fatty Acids: used for energy and movement into/out of cells2)Triglycerides: used for energy storage you know where3)Phospholipids: strongly amphipathicplasma membrane possible

-CH=CH- give lipid a “kink” (V.I.P.)

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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 LipidClassesNot Shown

Glycolipids like sphingomyelin

Terpenes like vitamin A