Steroid Structure Protein Structure and Function Proteins Polymers

Steroid Structure

Protein Structure and Function Ü Proteins Ü Polymers made of amino acid monomers Ü Amino acids: Ü Central carbon bonded to carboxyl Ü Amino group Ü Hydrogen Atom Ü R group

Peptide Bonds Ü Peptide Bond Ü Link amino acids Ü dehydration synthesis Protein function depends On # and order of amino acids

Four levels of protein structure Ü Primary: sequence of amino acids Ü Secondary: refers to one of two 3 D structures that result from H bonding Ü Alpha helix “spring” Ü Beta pleated sheet “accordion” Ü Tertiary: Complex globular shape Ü Result of interactions between R groups Ü Hydrophobic interactions Ü Van der Waals Ü Disulfide bridges Ü Quaternary: two or more polypeptides forming one large protein.

Levels of Protein Structure

Shape Dictates Function Ü Improper protein folding can lead to a variety of diseases Ü Cancer Ü Sickle-cell disease: abnormal hemoglobin Ü Prions Ü Alhezimers disease Ü Chaperonins: Ü assist in proper folding Ü Provide proper folding environment Ü Denaturation Ü Protein looses shape and or function Ü Heat Ü p. H Ü Salt concentrations

Chaperonin

Alzheimer's disease Ü Beta-amyloid is a fragment from a larger protein called amyloid precursor protein APP. Ü Cut by enzymes Ü Leads to plaque formation Ü Plaques disrupt calcium concentration, accumulate on mitochondria, induce apoptosis

Magnetic Resonance Imaging Ü Research from Drs. Yang and Meadowcroft at the Penn State Hershey Med Center, Center for Nuclear Magnetic Resonance Research.

Nucleic Acids Ü Store and transmit hereditary information Ü DNA (deoxyribonucleic acid) Ü RNA (ribonucleic acid) Ü Both have monomer nucleotides Ü Nucleotides 3 parts Ü Nitrogenous Base: adenine, thymine, cytosine, guanine, uralic Ü Pentose: 5 carbon sugar Ü Phosphate:

Nucleic Acid Structure

DNA & RNA Ü DNA is the molecule of heredity Ü Double stranded helix Ü Composed of Ü Adenine Ü Thymine Ü Cytosine Ü Guanine Ü G bonds C Ü A bonds T Ü RNA Ü Single Stranded Ü Composed of Ü Adenine Ü Cytosine Ü Guanine Ü Uracil

Monomer & Polymer Summary Table Macromolecule/P olymer Monomers/Comp onents Examples Functions Carbohydrates Monosaccharides Sugar, starch, glycogen, cellulose Energy, energy storage, structural Lipids Fatty Acids and Glycerol Fats, Oils Energy source, insulation Proteins Amino Acids Hmoglobin, Ppsin Enzymes, movemnent Nucleic Acids Nucleotides DNA, RNA Heredity; code for amino acid sequence

Concept Check 1. Which two functional groups are always found in amino acids? 2. Describe why phospholipids are important components of cell membranes, based on their structure and properties 3. Hydrolysis is involved in 1. 2. 3. 4. 5. 4. A. Formation of starch B. hydrogen bond formation between nucleic acids C. Peptide bond formation of proteins They hydrophilic interactions of lipids The digestion of maltose to glucose Compare and Contrast DNA vs RNA

Concept Check Responses 1. Carboxyl (the acid part), amino (the amino part) 2. Polar head, apolar tail, bilayer, fluid, semipermeable membrane 3. E is correct, hydrolysis, hydro-water, lysis-splits. Look for a large polymer split to monomer. 4. DNA double stranded RNA Single stranded, DNA Thymidine, RNA Uracil, DNA deoxyribose, RNA ribose