Chapter 2 Molecular Interactions

Chapter 2 Molecular Interactions - Or, Chemistry class in...

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Unformatted text preview: Or, Chemistry class in one lecture! Key Concepts Elements, Atoms, Isotopes etc. Chemical formulas, Chemical bonds Solutions, Concentrations, pH Organic Chemistry / Biochemistry The number of protons and neutrons in a nucleus of an atom constitutes the A. Atomic weight B. Atomic number C. Atomic mass D. Nuclear number The bond between an oxygen and a hydrogen in a water molecule is a(n) A. Non-polar covalent bond B. Polar covalent bond C. Hydrogen bond D. Ionic bond Deuterium and Tritium are examples of A. elements B. Ions C. Buffering compounds D. Isotopes E. None of these Element = Building block of matter Contains only atoms with same # of protons Periodic Table of the Elements (See also Fig 2-2) In human: 11 major essential elements COHNSPMgKCaFe + trace elements Organic Chemistry = Chemistry of Carbon Structure of Atoms (AKA elements) Fig 2-3 • Some Terminology: – – – – Atomic Number Atomic mass Ion Isotope Fig 2.1 Isotopes = Atoms of an element that have different numbers of neutrons. Same Atomic Number, variable Atomic Mass Most common Much rarer Heavy water = ? Some isotopes are unstable: Radioisotopes 3 types of radiation: 1. α radiation – protons and neutrons 1. (If protons are emitted, the element changes!) 2. β radiation - electrons 3. γ radiation: high energy waves, not particles More stable atom of same element Nuclear Medicine: use of radioisotopes in Nuclear diagnosis & treatment of disease. I is “normal” iodine 131 I has 4 extra neutrons 127 α and β radiation Medical Imaging ? Treatment? Importance of Electrons in Physiology • Ion formation = gain or loss of electrons • Bond formation between atoms ⇒ molecules • Energy capture & transfer • Free radical formation Ions are often called electrolytes! Chemical Bonds – Ionic: electrons pulled from one atom to another: Na+ and Cl– Covalent: electrons shared equally: C --- C – Hydrogen: weak attraction between H atoms and O, N, and Fl. Causes surface tension in water. – Van der Waal’s forces: weak attractions between nuclei of atoms Ionic Bonding Fig 2-4 Important Ions in Physiology cations anions Covalent bond: Water The electrons are shared equally If two electrons are shared, that is a “double bond.” Polar covalent molecule Non-polar covalent molecules Consequence: ions and polar molecules dissolve well in water Hydrogen bonds Hydrogen = weak attraction between H and nearby O, N or F. Critical for protein structure Hydrogen bonding of H2O leads to important characteristics: Liquid at RT Universal solvent for polar molecules Temp. buffer / frozen water less dense Capillary action Surface tension Solutions, concentrations and pH will be covered in lab. Refer to textbook when doing the lab exercises. The atomic mass of an atom indicates the average total number of A. Protons B. Neutrons C. Electrons D. Protons and neutrons E. Protons and electrons Elements that have full outer shells of electrons A. Will form many compounds B. Will normally form anions C. Will normally form cations D. Frequently form hydrogen bonds E. Are inert, and don’t bond readily with other atoms When a molecule is referred to as polar, it means that A. The positive and negative charges of the molecule are unevenly distributed B. The molecule has ionized and now carries a charge C. The molecule is likely to dissolve in water D. A and C are true E. A, B, and C are true Organic Chemistry / Biochemistry Biomolecules ( = organic molecules associated with living organisms) living 1) Protein 2) Fat (lipid) 3) CHO 4) Nucleotides •2 common features of biomolecules ?? •Carbon Backbone •Presence of C, H, O Functional Groups = partial molecules. Frequently occur in biological molecules. Moved around as a single units. Often make a big difference in the strength or function of a molecule Which of the following statements about proteins is false? A. All proteins are enzymes B. A given protein may contain over twenty different amino acids C. The tertiary structure of a protein results from interactions between its amino acids D. Proteins are gigantic polypeptides E. All of the above statements are true. Which of the following nucleotide bases in DNA can form H-bonds with the base adenine? A. Thymine B. Uracil C. Guanine D. Cytosine E. Both A and B Carbohydrates Carbohydrates See Fig 2-7 • Basic formula ? (see name!!) • Monosaccharides – examples ?? = simple sugars • Disaccharides – examples ?? • Polysaccharides – examples ?? = complex CHOs Fig 2-13: Monosaccharides Fructose Disaccharides Sucrose Glucose = Dextrose Maltose Galactose Lactose Fig 2-7 Function?? Polysaccharides Polysaccharides • Function ? Storage! • Why is it better to store polysaccharides than monosaccharides for future energy use? Lipids Lipids • Most diverse group of biomolecules • Solid at room temp = fat; – liquid at RT = oil • Contain much less O2 than CHOs – Often long chains of C • 4 categories: Fatty Acids can be (un)saturated Mono-, di-, and triglycerides Phospholipids (polar) Steroids Eicosanoids (prostaglandins et al.) Functions? Unsaturated (mono- & polyunsaturated) fats are liquid at room temp. Trans fats have added hydrogen (hydrogenated) (p 29) Triglycerides: 3 FA + Glycerol Saturated Unsaturated Polyunsaturated Phospholipids Steroids Cholesterol decreases cell membrane permeability to small water-soluble molecules. Function? Names of the 2 functional groups ? Proteins Proteins • Made up of amino acids – Amino = - NH2 • Peptide → oligopeptide → polypeptide → protein • Most versatile of biomolecules in structure and function Learn these Globular protein This picture illustrates the hydrophobic core of protein ras p21 The backbone is colored purple, and the hydrophobic residues are colored green. All the hydrophilic residues in the protein are colored yellow. Combination Molecules Combination • Lipoproteins in cell membranes and carriers for hydrophobic molecules (e.g.?) • Glycoproteins in cell membranes (stability, receptors, markers) • Glycolipids Nucleotides and Nucleic Acids • A–C–G–T–U • ATP, ADP, cAMP, FAD, NAD • Differences of DNA and RNAs • Function – information storage – info and energy transmission complementary basepairing Chromatin = DNA + proteins Euchromatin = active Heterochromatin = inactive Some Nucleotides are Involved in Some Energy Transfer ATP ADP NAD & FAD or Info Transfer cAMP A polypeptide consists of 100 amino acids. How many peptide bonds does it contain? A. 50 B. 100 C. 99 D. 101 E. Impossible to say without knowing the exact amino acid composition Each of the following is a function of proteins except one. Identify the exception. A. Support and structure B. Transport C. Carrying of messages D. Body defense E. Storage of genetic information A fatty acid that contains three double bonds in its carbon chain is said to be A. Saturated B. Monounsaturated C. Polyunsaturated D. Hydrogenated E. carboxylated Magnesium atoms have two electrons in the outermost shell and chlorine atoms have seven. The compound magnesium chloride would contain A. 1 magnesium and 1 chlorine B. 1 magnesium and 2 chlorine C. 2 magnesium and 1 chlorine D. 2 magnesium and 7 chlorine E. Impossible to tell without more info ...
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This note was uploaded on 12/24/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.

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Chapter 2 Molecular Interactions - Or, Chemistry class in...

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