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116 Cards in this Set
- Front
- Back
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homeostasis
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tendency of an organism to regulate and maintain relative internal stability
Claude Bernard coined the term in the 1800's |
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physiology
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the study of how living things function
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adaptation
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a gradual change over many generations
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acclimatization
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a change in an individual over its lifetime of biochemical or anatomical alterations
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acclimation
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like acclimatization but induced by experimentation
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feedback
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controlling mechanism by which homeostasis is achieved
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August Krogh Principle
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there is an animal optimally suited to yield an answer of a physiologically problem to be addressed
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acid
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any substance that can donate a proton
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base
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any substance that can accept a proton
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water
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polar; can be used to interact with other ions
lets NaCl dissolve in body fluids needed for the rapid transport of ions |
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pH scale
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1-12
1-6= acidic (gastric juices, vinegar, interior of lysosomes, cytoplasm of muscles) 7= neutral (water) 8-12= basic (salt water, ammonia, lime sol'n, alkaline lakes) |
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saturated
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each carbon has single bonds and is saturated with hydrogens
-MP: increased - solid fat at room temperature (single, solid, SATURATED) - easily converts to sterols (i.e. cholesterol) |
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unsaturated
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some carbons have double or triple bonds and therefore are not saturated with hydrogens
MP: decreased -form oils (liquid) or soft fats at room temperature |
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cholesterol
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needed for steroid-based hormone production
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high energy content: fats, proteins, or carbs?
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fats> proteins> carbs
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Types of fats
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lipids, phospholipids, waxes
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phospholipids
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hydrophilic head, hydrophobic tail
membrane bi-layer |
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waxes
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waterproof surface of insects
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proteins
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comprise 1/2 the dry weight in cells
have primary, secondary, tertiary, and quaternary structures |
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solvation/ hydration
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clustering of water molecules about individual ions and polar molecules.
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avogadro's number
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-used to convert units to and from moles
- +6.00 * 10^23 |
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colligative properties
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properties that depend on the total number of solute particles in a given volume, irrespective of their chemical nature
ex: osmotice pressure, depression of the freezing pt, elevation of the bp, depression of the water vapor pressure. - quantitatively related to the number of solute particles dissolved in a given volume of solvent. |
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osmolarity vs. molarity
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-equivalent for solutions of ideal nondissociating solutes exhipiting the same colligative properties
- not equivalent for electrolyte solutions because of ionic dissociation. |
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activity
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effective free concentration of an electrolyte as indicated by its colligative properties
- coefficient is "y" (gamma) |
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strong vs. weak electrolytes
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strong: electrolytes that dissociate to a large extent (large activity coeff.)
weak: electrolytes that dissociate only slightly |
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amphoteric
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can act as a base or an acid
example: water |
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pH = ?
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pH= -log[H+]
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Kw=?
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Kw = [H+][OH-] = 10^-14
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zwitterion
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the dipolar configuration that amino acids normally exist in solution (charges expressed)
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cathode/ anode
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cations (+) travel toward cathode (-)
anions (-) travel toward anode (+) |
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pH = pK` + log ([proton acceptor] / [proton donor])
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Henderson- Hasselbach equation
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pK`= -log K`
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pK`=11 then K`= 10^-11
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low pK`= strong acid
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high pK` = weak acid
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water conductivity
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- rate of charge transfer caused by migration of ions under charge difference.
- is greater than that of oils and other nonpolar liquids - electrons, which carry charge in semiconductors and metals, play no direct role in electric current in aq. soln's - greatly enhanced by addition of electrolytes which dissociate into cations and anions |
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voltage
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-difference in potential existing between separated (-) and (+) charges.
- is related to current (I) and resistance (R) as described by Ohm's law |
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factors that determine resistance to current flow in solution
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- ion concentration (more dilute soln= higher resistance, lower conductivity)
- cross-sectional area of solution (smaller the area, higher resistance encountered by the current) -distance traversed in solution by current (total R encountered by current passing through soln is directly proportionate to distance current traverses) |
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4 types of biological molecules
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lipids, proteins, carbohydrates, amino acids
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lipids
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water-insoluble with relatively simple chemical structures.
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Fat
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serves as an energy store, composed of triglyceride molecules (glycerol + 3 fatty acids connected by ester linkages)
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phospholipids, sterols
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major components of membranes
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what determines the physical properties of a fat?
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degree of saturation and length of fatty acid chain.
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carbohydrates
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(CH2O)n
- monosaccharides < disaccharides < polysaccharides |
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monosaccharides
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-most common are pentoses (5C) and hexoses (6C)
- typically exist in ring structure - 2 most important pentose sugars: ribose and 2-deoxyribose (backbones of all nucleic acids) |
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Green plants manufacture glucose by PHOTOSYNTHESIS
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Glucose used and broken down for energy in CELLULAR RESPIRATION
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cellular respiration
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- complete or partial degradation of glucose to water and carbon dioxide
- releases chemical energy stored in structure of glucose during photosynthesis. |
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polymers of glucose used for storage
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starch - plants
glycogen- animals |
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main structural substance of plants
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cellulose (unbranched polymer of d-glucose)
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chitin
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major constituent of exoskeletons of insects and crustaceans
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primary structure
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specific linear sequence of amino acids in a polypeptide
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secondary structure
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the local organization of parts of the polypeptide chain, which can assume several different arrangements.
- alpha helix, beta-pleated sheet |
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tertiary structure
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foldings of the chain to produce globular or rodlike molecules
- stabilized by van der Waals forces (weak attractions between nonpolar groups) and disulfide linkages (covalently joins residues) |
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quaternary structure
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joining of two or more polypeptide chains to form dimers, trimers, and larger aggregates
- heme group, hydrogen bonding |
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denaturation of protein
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heating a protein disrupts the noncovalent interactions (VDW, h-bonding, electrostatic interactions) that stabilize the protein and reduces it to a disordered state.
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molecular chaperones
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family of proteins that features prominently in the folding of other proteins and the preservation of their complex folded states.
> assist in the folding of newly synthesized proteins > bind to and stabilize proteins that are partially unfolded or improperly folded, protecting them from degradation > rescuing the cell after environmental insult such as heat shock |
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heat-shock proteins
stress proteins |
a.k.a. molecular chaperones
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DNA (deoxyribonucleic acid)
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carries coded information arranged into genes that is passed from each cell to its daughter cells and from one generation of organisms to the next
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RNA (ribonucleic acid)
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instrumental in translating the coded message of DNA into sequences of amino acids during synthesis of protein molecules
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nucleic acids
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polymers of nucleotides, each of which consists of a pyrimidine or purine base, a pentose sugar, and a phosphate residue.
-phosphodiester linkages join the carbon rings together |
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DNA nucleotides
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contain deoxyribose and the bases adenine, thymine, guanine, and cytosine
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RNA nucleotides
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contain ribose and the bases adenine, uracil, guanine, and cytosine
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transcription
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DNA strand acts as a template for synthesis of mRNA in the cell nucleus
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translation
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mRNA strand leaves nucleus and enters cytoplasm, where it is decoded by a ribosome into the amino acid sequence of a polypeptide chain.
- tRNA matches codons to anticodons and create the polypeptide |
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metabolism
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material and energy transactions that take place in an organism
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metabolic pathways
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intricate reaction sequences at an intracellular level in which a single cell can involve thousands of different kinds of reactions
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energy
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capacity to do work
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work
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product of force times distance (w= f*d)
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first law of thermodynamics
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energy is neither created nor lost in the universe
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second law of thermodynamics
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energy of the universe wll inevitably be degraded to heat and the organization of matter will tend toward entropy
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Gibbs free energy eq
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change in free energy (G) = change in enthalpy (H) - T * change in entropy (S)
delta G = delta H - T * delta S |
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endergonic reaction
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reaction which requires the input of energy
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exergonic reaction
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reactions which release energy (heat)
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dG = -RTlnK`eq
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if K`eq > 0, dG <0;
if K`eq < 0, dG >0 |
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what do enzymes do to activation energy and free energy change?
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- enzymes lower activation energy doesn't affect overall free energy change (dG)
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catalysts
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substances that are neither consumed nor altered by a reaction, but facilitate the interaction of the reactant particles.
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enzymes may:
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> hold substrate molecules in a particular orientation
> for unstable intermediate with substrate so that it then readily moves to the final product > have side groups within active site that act as proton donors/ acceptors in acid-base rxns |
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enzyme saturation
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when all enzyme molecules can become tied up as ES if substrate conc. is high enough relative to enzyme conc.
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optimal pH and temperature
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enzyme activity will increase to a optimal point in both factors, but will denature if that point is passed
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where does energy kept in cells?
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organelles
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different forms of energy
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thermal, mechanical, etc.
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ATP --> ADP; energy lost
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ADP --> ATP; energy required
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chymotrypsin
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hydrolyzes any peptide bond in qhich the carbonyl group belongs to a phenylalanine, tyrosine, or tryptophan residue
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Ohm's law
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I = V/R
strength of current (I) varies directly with voltage (V) and inversely with resistance (R) |
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coupled reaction
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the ability of one reaction to drive another, depending on the amount of energy one outputs and how much the other requires to begin
(example: exergonic rxn drives an endergonic rxn) |
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Km (Michaelis- Menten constant)
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the substrate concentration at which the initial rxn rate is half what it would be if the substrate were present to saturation.
- the concentration of substrate at which half the total enzyme present is combined with substrate in ES - greater the affinity between an enzyme and its substrate, the lower the Km of the enzyme for its substrate. - doesn't depend on enzyme concentration whereas Vmax does. |
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Lineweaver-Burk eq
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m = -Km/ vmax
x-int = -1/Km y-int= 1/vmax plotted: 1/Vo (y axis) / 1/[S] (x axis) |
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competitive inhibition
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molecules that appear to react directly with active site; can be reversed by increase in substrate conc.
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noncompetitive inhibition
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molecules that bind to a region of enzyme outside of active site and change the enzyme conformation so it can't bond to substrate.
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competitive graphing
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1. binds at active site
2. increase in [I] more blockage until saturated (alter rate and increase Km, w/o change on Vmax) 3. Increases in [S] removes inhibition 4. slope changes |
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noncompetitive graphing
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1. doesn't bind at active site
2. Increase in [S] no effect 3. Increase in [I]more block til saturated (no change on Km, but decrease in Vmax) 4. Slope changes |
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end-product inhibition
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limits the rate of accumulation of end product by slowing the entire sequence from the beginning.
Enz1>Enz2>Enz3>Enz4>product> inhibits use of Enz1 |
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gap junctions
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provide a means of communication between cells by allowing inorganic ions and small water-soluble molecules to pass directly from the cytosol of once cell to the cytosol of another.
- couple cells both electetically and metabolically with important functional consequences for the tissue ex: fluorescein and procion yellow |
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tight junctions
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seal cells together into an epithelial sheet but don't proeide a channel; even small molecules can't get from one side of the sheet to another.
substances can only pass through the ends of cells (transcellutlar) but not around them (paracellular) |
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serosal
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internal
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mucosal
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external
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frog skin
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studied icompartment tacing the mucosal side is designated the outer compartment, serosal- the inside compartment. solutions are oxygenated. tested how ions could pass through membrane, learning about the Na+/K+ pump (epithelial salt transport)
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water transport
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1) by a specific carrier mechanism driven by metabolic energy
2) by osmosis as a consequence of solute transport. |
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nervous and endocrine systems
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contribute to coordination within an animal's body
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neurons
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nerve cells
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soma
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cell body
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dendrites
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extend from soma; serve as receivers that gahter signals from other neurons
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axons
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extensions of neuron; conduct signals away from soma
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spike initiating zone
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integrates signals from many input neurons
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action potential (AP)
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voltage across plasma membrane rapidly rises and then falls.
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passive electrical properties
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capacitance, resistance
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active electrical properties
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allow neurons to conduct electrical signals without loss of signal strength
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afferent fiber
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axon of sensroy neuron
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synapses
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gap between neurons
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eferent
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nurons that carry info away from processing regions
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all or none signals
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signals whose amplitude is invariant
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graded signals
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signals whose amplitude varies
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glial cells
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fill space between neurons.
CNS contains 10-50 glials more than neurons and they occupy about 1/2 volume of nervous system |
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schwann cells
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glial cells that wrap axons in insulating myelin sheath
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membrane potential
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potential difference m that exists across a membrane
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resting potential
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steady inside-negative potential recorded when no action potentials or postsynaptic events are occuring
between -20 and -100mV |
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depolarization
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diminishing of the potential difference across the membrane.
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threshold
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value of mp at which an ap is triggered 50% o the time.
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