The   Energy Page

I. Some Forms of Energy 
    1. Light energy
    2. Heat energy
    3. Electrical energy
    4. Chemical energy
    5. Mechanical energy

II. Law of conservation of energy: Energy cannot be created nor destroyed, but can change form.  (With the exception of some rare nuclear fusion/fission reactions)

III. Types of energy
    1. Potential Energy-- stored energy
    2. Kinetic Energy-- energy of work or motion

IV. Energy and Chemical reactions
    1. Endergonic reactions
            A. Reactions that require energy
            B. These reactions are usually anabolic or synthesizing
                 reactions.
            C. Energy is usually required for new bonds to form.
            D. These reactions result in molecules with a greater
                 potential energy.

    2. Exergonic reactions
            A. Reactions that release energy
            B. These reactions are usally catabolic or "breaking
                 down" reactions.
            C. Energy is usually released when bonds are broken.
            D. These reactions result in molecules with less
                 potential energy.

    3. Activation energy
            A. The energy required by ALL chemical
                 reactions to get started.
            B. In the lab, this energy is usually supplied by heat.
            C. In living things,  this energy is supplied by ATP.
            D. In living things, this energy requirement is lowered
              by using enzymes.

    4. ATP
            A. Adenosine triphosphate (name)
            B. Consists of adenine (base) connected to ribose (sugar)
                connected to 3 phosphate groups.
            C. Symbolized as:  ("A" represents  adenine-ribose)
                    1. Adenosine triphosphate:         ATP:     A-P~P~P
                    2. Adenosine diphosphate:         ADP:     A-P~P
                    3. Adenosine monophosphate:   AMP:     A-P
            D. Bonds
                    1. -P bonds are very stable, have low potential energy
                    2. ~P bonds are very unstable, have a great deal
                        of potential energy
                    3. ~bonds were once called "high energy bonds" but
                        students misunderstood this to mean very strong
                        bonds, when in fact these bonds are very weak
                        and unstable.
            E. Formation of ATP--
                    1. Requires lots of energy
                            a.      A-P    + P  + energy --->   A-P~P
                                   (AMP  + P  + energy --->   ADP)

                            b.     A-P~P  +  P  +  energy ---->   A-P~P~P
                                   (ADP    +  P  +   energy ---->    ATP)
 
                    2. Occurs during cellular respiration in the
                        mitochondria of cells.

            F. Breakdown of ATP and ADP-->
                    1. Releases a lot of energy
                            a. A-P~P~P   --->  A-P~P  +  P  + ENERGY
                            b. A-P~P   --->      A-P  +  P  +    ENERGY
                    2. Occurs in every cell of an organism whenever the
                        organism needs energy.

V. Energy and Organisms

RETURN TO MRS. PELLEGRINI'S  BIOLOGY HOMEPAGE

©1998 Linda Pellegrini. All rights reserved.