Energy and OrganismsCh. 2-2

Importance:

-All living organisms use energy.-Amount of energy in the universe remains the same over time, but changes from one form to another.-Biologist study the transfer of energy from the sun to and through almost every organism.

Energy:

-Energy is defined as the ability to do work.-Energy occurs in various forms:

1. chemical2. thermal3. electrical4. mechanical5. radiant

Energy & Chemical Reactions:

-Living organisms are constantly undergoing thousands of chemical reactions.

-Energy is absorbed (endergonic) or released (exergonic) when chemical bonds are broken and new ones are formed.

-Your body takes in carb’s, lipids, and proteins (reactants) and chemically breaks them down into carbon dioxide, water, and other substances (products).

-This process is called your metabolism. These reactions release energy which is used to:

-maintain body cells, tissues, and organs.

Chemical Reactions and the need of Enzymes:

-For a majority of the chemical reactions to occur effectively in our metabolism, energy needs to be added first. This is called the activation energy.

-To make the metabolic process more efficient, our bodies created a specialized substance known as a catalyst (enzymes in living organisms) to reduce the amount of activation energy required therefore speeding up the reaction.

Understanding Enzymes:

-enzymes are proteins or RNA molecules that speed up metabolic reactions. Enzymes can alter/affect proteins.

-enzymes are specific to their job they perform in living organisms.

-enzymes generally have the suffix –ase. Example: Lipase

-different enzymes have different shapes that are specific to their function. (lock & key model)

-enzyme function will vary based upon the temperature or pH level they are exposed to.

Oxidation-Reduction Reactions-Recall: there is a constant transfer of energy into and throughout living organisms.

-The chemical reactions that help the transfer of energy involve the transfer of electrons.

-These reactions are called Oxidation-Reduction reactions or Redox Reactions.

oxidation or being oxidized = reactant loses one or more electrons.

reduction or being reduced = reactant gains one or more electrons.

-Redox reactions always occur together.