Objectives. in living cells.

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1 Objectives The studient will know the definition of matter, energy potential energy and kinetic energy. the student will be able to define element and be able to list the elements that make up most of the body. The student will be able to define atom and describe the subatomic particles found in it. The student will be able to define atomic number, atomic mass, isotope, radioisotope, and molecule. The sudent will know the difference between compound and mixture, a solution and a suspension. The student will know the role of electrons in chemical bonding in relation to the octet rule. The student will differentiate between ionic, covalent and hydrogen bonds. The student will be able to identify the major types of chemical reactions: synthesis, decomposition, exchange and oxidation-reduction reactions. The student will be able to explain the properties of water and its importance to body homeostasis. The student will be able to define ph, acid, base, and buffer. The student will be able to describe concepts about each of the four types of organic compounds. Including what elements are most common to each, their monomers, and their functions. The student will be able to explain dehydration synthesis and hydrolysis in relation to the major organic compounds. The student will be able to describe the general suructure of protein and the four levels of protein structure. The student will be able to explain the general mechanism of enzyme activity. The student will know the structure and role of ATP in living cells.

2 Dr. Prince, what are the parts of the atom? The positively charged protons and the uncharged neutrons are located in the center or the nucleus of the atom. The negatively charged electrons, equal in number to the protons, orbit the nucleus in various energy levels, depending on the total number of electrons. Dr. Prince could you explain ionic vs covalent bonds. Chemical bonding involves either donating or receiving electrons or sharing electrons between atoms. In an ionic bond atoms are held together by the opposite electrical charges created by donating or receiving electrons. In a covalent bond, two atoms share electrons to stabilize their outer electron orbitals without loss or gain of electrons. Most organic compounds are held together by covalent bonds. Electrolytes are held together by ionic bonds. General functions of water. Solvent - due to polar covalent bonds, tends to pull ionic compounds apart Participant in chemical reactions - digestive breakdown of molecules via hydrolysis or formation of larger molecules via dehydration synthesis Maintenance of body temperature - great heat absorbing capacity without large increases in temperature, a high heat of vaporization provides excellent cooling mechanism as sweat evaportates Acts as a lubricant - as major part of mucus and other lubrication fluids to reduce friction between body parts Dr. Prince how do enzymes work? Enzymes are biological catalysts. Substrates are the molecules upon which enzymes work. Enzymes speed up chemical reactions by lowering the activation energy and properly orienting colliding molecules. There is a specific relationship between enzymes and their substrates. the enzyme has an active site that fits the substrate in a manner similar to a lock and key mechanism. The type of reaction catalyzed is also specific. DNA vs RNA DNA and RNA are both formed from nucleotides. DNA nucleotides contain deoxyribose a phosphate group and a nitrogenous base (A,T,C,G). RNA nucleotides contain ribose, a phosphate group and nitrogenous base (A,U,C,G). DNA molecules are made of two strands of nucleotides joined by complementary base pairing (A-T and G-C). RNA are single stranded nucleotides, and are much shorter than DNA. Help with HYDROLYSIS! Hydrolysis is the breakdown of larger molecules into smaller units by the addition of water. The major groups of biochemicals are degested via

3 hydrolysis reactions in the intestinal tract. Matter Energy Chapter 2 Chemistry Comes Alive The "stuff" of the universe everything" Anything that has mass and takes up space States of matter Solid Liquid Gas The capacity to do work (put matter into motion) Types of energy Kinetic energy of motion Potential energy of position; stored (inactive) energy such as that found in chemical bonds Forms of Energy Chemical stored in the bonds

4 Electrical from the movement of charged particles Mechanical directly moving matter Radiant or electromagnetic energy traveling in waves (i.e., visible light, ultraviolet light, and X rays) Energy Form Conversions Energy can be converted from one form to another During conversion, some energy is "lost" as heat (when you convert the energy in the food that you eat in to movement you give off heat) Composition of Matter Element "a type of matter" has unique physical and chemical properties Physical properties those detected with our senses Chemical properties how atoms interact with one another Atoms the smallest amount of an element that retains the properties of the element Atomic symbol one- or two-letter chemical shorthand for each element Major Elements of the Human Body Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N) These make up about 96% of your body

5 "CHONes" Other elements 3.9% of the body: Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe) Trace elements make up less than 0.01% of the body Atomic Structure The nucleus consists of neutrons (no charge) and protons (positive charge) Each have a mass of one atomic mass unit (amu) Electrons are found orbiting the nucleus (negative charge) Have a mass of 0 amu (for us "no mass") Identification of Elements Atomic number equal to the number of protons it is the atoms "identity" Mass number equal to the mass of the protons and neutrons Atomic weight average of the mass numbers of all isotopes Isotope atoms with same number of protons but a different number of neutrons (atoms of the same

6 element that have different atomic masses) Molecules and Compounds Molecule two or more atoms held together by chemical bonds Compound is a molecule made of two or more different elements Solutions and Suspensions Solutions homogeneous mixtures of components Solvent substance present in greatest amount Solute substance(s) present in smaller amounts Suspensions are heterogeneous mixtures with visible solutes that tend to settle out Concentration of Solutions Molarity, or moles per liter (M) A mole of an element or compound is equal to its atomic or molecular weight (sum of atomic weights) in grams Chemical Bonds Electron shells, or energy levels, surround the nucleus of an atom Bonds are formed using the electrons in the

7 outermost energy level (valence electrons) to be "happy campers" Octet rule except for the first shell which is full with two electrons, atoms interact to have eight electrons in their valence shell to be "happy campers" Chemically Inert Elements Inert elements have their outermost energy level fully occupied by electrons Chemically Reactive Elements Reactive elements do not have their outermost energy level fully occupied by electrons "NOT happy campers" Types of Chemical Bonds To become "happy campers" atoms will lose, gain, or share valance electrons this results in chemical bonds Ionic Covalent Hydrogen Ionic Bonds Ions are charged particles resulting from the gain or

8 loss of electrons Anions have gained one or more electrons and have an overall negative charge Cations have lost one or more electrons and thus have an overall positive charge Formation of an Ionic Bond In Ionic bonds there is an actual loss and gain (transfer) of one or more electrons Ionic compounds form crystals instead of individual molecules Example: NaCl (sodium chloride) Covalent Bonds Covalent bonds are formed by the sharing of two or more electrons Electron sharing produces molecules Polar Molecules Unequal sharing of electrons produces polar molecules Electronegative is when an atom attracts electrons Atoms with six or seven valence shell electrons are electronegative like O & N

9 Hydrogen Bonds Chemical Reactions Occur when chemical bonds are formed, rearranged, or broken Are written in symbolic form using chemical equations Types Chemical Reactions Synthesis reactions which always involve bond formation A + B AB Decomposition reactions: Molecules are broken down into smaller molecules AB A + B Exchange reactions: Bonds are both made and broken AB + C AC + B Oxidation-Reduction (Redox) Reactions Reactants losing electrons are oxidized Reactants that gain electrons are reduced When an atom is oxidized another is always reduced! Energy Flow in Chemical Reactions

10 Exergonic reactions reactions that release energy Endergonic reactions reactions that consume energy Factors Influencing Rate of Chemical Reactions Temperature chemical reactions proceed quicker at higher temperatures Particle size the smaller the particle the faster the chemical reaction Concentration higher reacting particle concentrations produce faster reactions Catalysts increase the rate of a reaction without being chemically changed Enzymes are biological catalysts Biochemistry Organic compounds Contain carbon, are covalently bonded, and are often large Inorganic compounds Do not contain carbon Water, salts, and many acids and bases Properties of Water

11 High heat capacity absorbs and releases large amounts of heat before changing temperature High heat of vaporization requires large amounts of heat to evaporate Polar solvent properties dissolves ionic substances, forms hydration layers around large charged molecules, and serves as the body s major transport medium Reactivity is an important part of hydrolysis and dehydration synthesis reactions Cushioning resilient cushion around certain body organs Acids, Bases and Salts Inorganic compounds Are electrolytes; they conduct electrical currents Acids release H + and are therefore proton donors HCl H + + Cl Bases release OH and are proton acceptors NaOH Na + + OH Salts release cations other than H + and anions other than OH Acid-Base Concentration (ph) Acidic solutions have higher H + concentration and a lower ph # Alkaline solutions have lower H + concentration and a higher ph # Neutral solutions have equal H + and OH

12 concentrations and a ph of 7 Buffers Acidic: ph Basic: ph Neutral: ph 7.00 Anything that resists change ph buffers resist abrupt and large changes in ph Carbonic acid-bicarbonate system Organic Compounds Molecules unique to living systems contain carbon and hence are organic compounds They include: Carbohydrates Lipids Proteins Nucleic Acids Carbohydrates Contain C, H, and O Their major function is to supply a source of cellular

13 food Lipids Always have a 2:1 H:O ratio Monosaccharides or simple sugars Disaccharides or double sugars Polysaccharides or polymers of simple sugars Contain C, H, and O, but no 2:1 ratio of H to O Examples: Neutral fats or triglycerides Phospholipids Steroids Neutral Fats (Triglycerides) Composed of three fatty acids bonded to a glycerol molecule Other Lipids Phospholipids modified triglycerides with two fatty acid groups and a phosphorus group Other Lipids Steroids flat molecules with four interlocking hydrocarbon rings Eicosanoids 20-carbon fatty acids found in cell membranes

14 Representative Lipids Found in the Body Neutral fats found in subcutaneous tissue and around organs Phospholipids chief component of cell membranes Steroids cholesterol, bile salts, vitamin D, sex hormones, and adrenal cortical hormones Protein Fat-soluble vitamins vitamins A, E, and K Eicosanoids prostaglandins, leukotriens, and thromboxanes Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Structural Levels of Proteins Primary amino acid sequence Secondary alpha helices or beta pleated sheets Tertiary superimposed folding of secondary structures Quaternary polypeptide chains linked together in a specific manner Fibrous and Globular Proteins Fibrous proteins Strandlike proteins like keratin, elastin, collagen, and contractile

15 fibers found in muscle Globular proteins Compact, spherical proteins with tertiary and quaternary structures like antibodies, hormones, and enzymes Protein Inactivation Reversible unfolding of proteins due to drops in ph and/or increased temperature Protein Denuaturation Irreversibly change and cannot refold due to extreme ph or temperature changes Characteristics of Enzymes Most are globular proteins that act as biological catalysts Holoenzymes consist of an apoenzyme (protein) and a cofactor (usually an ion) Enzymes are chemically specific Frequently named for the type of reaction they catalyze and end in -ase Lower activation energy of a reaction Nucleic Acids Composed of C, O, H, N, and P

16 Their structural unit is the nucleotide made of a N- containing base, a pentose sugar, and a phosphate group Five nitrogen bases contribute to nucleotide structure adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U) Two major classes DNA and RNA Structure of DNA Deoxyribonucleic Acid (DNA) Replicates itself before the cell divides, ensuring genetic continuity (during the S phase of the cell cycle) Provides all the instructions for protein synthesis Ribonucleic Acid (RNA) Single-stranded molecule found in both the nucleus and the cytoplasm of a cell (smaller than DNA, much smaller) Uses the nitrogenous base uracil instead of thymine Three types of RNA: messenger RNA, transfer RNA, and ribosomal RNA Adenosine Triphosphate (ATP) How ATP Drives Cellular Work

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