09 15 2013 LECTURE ONE Characteristics of living systems A Metabolism sum of all cellular chemical processes Breakdown of large molecules into small to provide chemical energy for cells and body heat Construction of new structural components such as proteins B Responsiveness the ability to respond to change Detection and response to changes in internal or external environment Physiological signals include temperature cell electrical signals hormones and blood nutrient levels C Movement The body an organ a cell or cell component D Growth Differentiation Increase in number or size of cells or the material between cells Specialization of cells for a specific function E Reproduction Formation of new cells or new individuals LEVELS OF STRUCTURAL ORGANIZATION Chemical Atomic and molecular level Smallest living unit of the body Cellular Tissue Organ Level Organ system Organismic One living individual HOMEOSTASIS Claude Bernard Group of cells and the materials surrounding them that work together on one task Grouping of 2 or more tissue types into a structure Collection of related organs with a common function o The constancy of the internal environment is the condition for a free and independent life o The physical and chemical parameters of living systems tend to remain constant over time Living systems exist within limits of heat moisture pressure chemical composition Homeostasis is the condition which the body s internal environment remains relatively constant within physiological limits Negative feedback acting to reverse a change Changing something your body cannot detect Makes a decision in order to maintain body temperature and instructs effector Mediate response In this loop Original stimulus is reversed Most feedback systems in the body are negative Used for conditions that need frequent adjustment such as body temp blood sugar and blood pressure Positive feedback loop Original stimulus intensified Seen during normal childbirth A hypothesis is a tentative answer to the question it is not the Scientific method 1 Observation 2 Hypothesis and prediction question itself 3 Experimental testing 4 Analysis and conclusion Does the data support the hypothesis 5 Development of new hypothesis A constant state maintained through time is called steady state homeostasis A constant state achieved without energy expenditure is called equilibrium LECTURE TWO Protons are positive Electrons are negative The number of protons and electrons defines if the particle has a net neutral positive or negative charge Cations Anions Major elements Hydrogen 10 Carbon 18 Oxygen 65 Nitrogen 3 MOLECULE compound Assemblage of atoms same or different held together by chemical bonds Chemical bonds attach adjacent atoms by Sharing electrons covalent bond Using attractive force of electrical charge Ionic bond Covalent bonds outermost orbits Stability of atoms is influenced by the number of electrons in the Oxygen atom oxygen atom molecule oxygen gas O2 Nitrogen atom nitrogen atom molecule of nitrogen gas N2 Hydrogen Carbon methane Atoms Atoms molecule CH4 Sharing can be equal or non polar Sharing can be unequal Polar Ionic Bonds atom or atoms Sometimes one atoms donates one or more electrons to another o The atom that donates electrons then becomes an ion o The atom that accepts the electrons becomes negatively cations charged anion Covalent bonds share electrons The bond becomes ionic when the sharing becomes taking Hydrogen bonds The poles of polar covalent bonds have partial electrical charges Chemical reactions Making bonds release energy Breaking bonds require energy To break bonds you must input energy but you get a lot out Unequal sharing of electrons polar covalent Equally sharing in electrons is high energy Metabolism Is the manipulation of chemical energy in the form of chemical bonds Catalysts compounds that make reactions go faster by reducing the amount of energy required to get them started Solution mixture of two or more components Solutes are mixed in a solvent Any solution with water as its solvent is aqueous Dissolving a solute in water Molecules with polar or ionic bonds can interact with water molecules Water molecules can surround each particle solvating dissolving it thereby holding it in solution Concept of Concentration Amount of compound Unit of volume Concentration is a ratio Moles Liter Typical amount a mole is 6 10 23 Avogadro s number A mole of a compound A and a mole of a compound B may have different masses But they have the same number of particles Concept of pH The concentration of hydrogen ions H H o H is a naked proton and very reactive Tends to bind to some atoms and come off of others Adds or subtracts electrical charge and thereby influences structure and function of molecules Shorthand H concentration PH log H So if H 1 10 7 moles liter 0000001 mol liter o PH log 7 7 Buffer systems of the body The pH of body fluids is maintained within narrow ranges through the influence of buffering systems Buffers donate or pick up H ions keeping the total H relatively constant o Buffers are like sponges on H Adding or removing hydrogen to keep it constant o Mixture combination of elements or compounds that are physically blended together but not chemically bound Colloid solute particles are large enough to scatter light just as water droplets in a fog scatter light from a car s headlight beams When inorganic acids bases or salts dissolve in water they dissociate they separate into ions and become surrounded by water molecules Acid substance that dissociates in one or more hydrogen ions o Because H is a proton with one positive charge an acid is referred to as a proton donor and one or more anions Base a base removes H from a solution and is therefore a proton accepter o Many bases dissociate into one or more hydroxide ions OH and one or more cations Salts are important for carrying electrical currents Especially in nerve and muscular tissues These INS provide many essential chemical elements in intracellular and extracellular fluids such as blood lymph and interstitial fluid of tissues Acids and bases react with one anther to form salts Organic compounds Always contain carbon 1 Lipid C H primary energy storage 2 Carbs C H O 3 Protein C H O N 4 Nucleic acid C H O N P LIPIDS Lipids have a hydrocarbon tail a hydroxyl group and 4 rings CARBOHYDRATES One carbon one hydrogen and one oxygen PROTEIN NECLEIC ACIDS DNA AND RNA LECTURE THREE The cellular level of organization 1 cells are the building