Please enable JavaScript.

Coggle requires JavaScript to display documents.

Chapter 8 Intro to Metabolism the totality of an organism's…

- - - - Types of Energy & Association:
        Kinetic: the relative motion of objects
        Thermal: the random movement of atoms or molecules
        Potential: energy that matter possesses because of its location or structure
        Chemical: potential energy available for release in a chemical reaction
        
        Heat: thermal energy in transfer from one object to another
        
        Thermodynamics: the study of the energy transformations that occur in a collection of matter
        
        Isolated system: unable to exchange either energy or matter with its surroundings outside the system. Ex: Thermos bottle
        Open system: energy and matter can be transferred between the system and its surroundings. Ex: organisms
        
        Laws of Thermodynamics
        
        First Law (Principle of conversation of energy): the energy of the universe is constant" Energy can be transferred and transformed, but it cannot be created or destroyed.
        
        Second Law:* Every energy transfer or transformation increases the entropy of the universe*
        
        Entropy: a measure of molecular disorder, or randomness
        
        1 more item...
        
        the change in the system's entropy; T is the absolute temperature in Kelvin (K) units (K= C + 273
- - - - Free energy is the measure of a system's instability- its tendency to change to a more stable state
        < 0, negative: process occurs spontaneously in a system, the system must lose free energy during the change from initial state to final state
        = 0 Stable system:, a system at equilibrium cannot spontaneously change, it can do no work
        > 0, positive: less stable, storage of free energy
        
        More Stable (Lower G) Ex: Diver floating in water, Unstable systems (Higher G) Ex: Diver on platform
        
        Exergonic reactions: proceeds with a net release of free energy, chemical mixture loses free energy (G is negative, G decreases) as standard for spontaneity, release energy in one direction
        Endergonic Reactions: is one that absorbs free enerfy from its surroundings, the quantity of energy required to drive the reaction (G is positive, G increases), as a standard for non-spontaneous, using energy
- - - - ATP (adenosine triphosphate)
        
        contains sugar ribose, the nitrogenous base adenine and chain of three phosphate groups bonded to it
        
        also one of the nucleoside triphosphates used to make RNA
        
        useful to the cell because the energy it releases on losing a phosphate group is greater than the energy most molecules could deliver
        
        ATP Broken by Hydrolysis:
        
        Hydrolysis releases energy - referred to as high-energy phosphate bonds
        
        When ATP is hydrolyzed in organisms, the release of free energy - the cell's proteins harness the energy to perform cellular work: chemical, transport, and mechanical
        
        Phosphorylated intermediate: the recipient molecule with the phosphate group covalently bonded to it
        
        the key to coupling exergonic and endergonic reactions is this formation, more reactive than original molecule (less stable, with more free energy)
        
        How ATP drives Chemical Work
        
        How ATP drives Transport and Mechanical work
        
        ATP Cycle:
        
        How ATP is regenerated from ADP:
- - - - Transition state: when molecules have absorbed enough energy for the bonds to break, the reactants are in an unstable condition
        
        Enzyme's Substrate: this is the reactant an enzyme acts on is referred to as
        
        Enzyme-substrate complex: when the enzyme binds to its substrate (or substrates, when there are two or more reactants)
        
        Active Site: the only restricted region of the enzyme molecule that actually binds to the substrate, the pocket or groove on the surface of the enzyme where catalysis occurs
        
        Induced fit: the tightening of the binding after initial contact, like a clasping handshake
        
        brings chemical groups of active site into positions that enhance their ability to catalyze the chemical reaction
      - First: High Temperature or Change in pH denatures proteins and kills cells
        
        Up to a temp point, rate of enzymatic reaction increases with increasing temp
        
        Above that temp, the speed of the enzymatic reaction drops sharply, thermal agitation disrupts the Hydrogen bonds, iconic bonds, and other weak interactions that stabilize the enzyme shape
        
        Optimal Temp, allows the greatest # of molecular collisions and the fastest conversion of reactants to products
      - Second: Organisms carry out catalysis
        
        the process by which a catalyst selectively speeds up a reaction without itself being consumed.
        
        Heat would speed up all reactions, not just those that are needed.
        
        Lowers the E(a) barrier, enabling reactants to absorb energy to reach transition state at mod temps
        
        Enzymes cannot change for a reaction; it cannot make an endergonic reaction exergonic
    - - Noncompetitive inhibitors: do not directly compete with the substrate to bind to the enzyme at the active site, but can change the structure
      - Feedback Inhibition: the common mode of metabolic control, in which a metabolic ATP-generating pathway is halted by the inhibitory binding of its end product to an enzyme that acts early in the pathway
- - - - Self Regulation:
        Ex: If ATP production lags behind its use, ADP accumulates and activates the enzymes that speed yp catabolism, producing ATP. If the supply of ATP exceeds demand, then catabolism slows down as ATP molecules accumulate and bind to the same enzymes, inhibiting them.
      - Cooperativity: the mechanism amplifies the response of enzymes to substrates: one substrate primes an enzyme to act on another substrate more readily
        - Ex: Hemoglobin is not an enzyme but elucidate the principle