L4 Cell Metabolism Flashcards
Reaction requiring the addition of free energy
• Must be pushed “uphill”
•is the molecule used by organisms to power this reaction
- Enderggonic Reactions
- ATP
Energy in a system available to do work
Free energy
In molecules, it is the energy present in a chemical bonds minus the energy that cannot be used
Free energy
Some of these require small non protein groups,cofactors to perform enzymatic function.
Enzymes
Cofactor is organic
Coenzymes
Possess enzymatic activity
RNA
Reactants in enzymatic reactions
Substrates
Region of an enzyme to which the substrate binds
+ Located in cleft or oocket and has flexible surface that enfolds and conforms to the substrate
Active site
Binding if enzyme forms
Enzyme-substrate complex
Es complex
Enzymes may catalyze billions of reactions until worn out and degraded by in cell.
Scavenger enzyme
reactions are reversible reactions.
Most reactions tend to go predominantly in one direction.
Net direction of a reaction depends on relative energy contents of the substances involved.
If there is little change in chemical bond energy of substrate and products, then the reaction is more easily reversible.
Enzyme catalyze reactions
If large quantities of energy are released as the reaction proceeds, more energy must be provided to drive the reaction in the
Reversing a reaction
function of many enzymes is tightly controlled.
Quantity of enzymes regulated by molecules that switch on or off enzyme synthesis
Activity of enzymes controlled by presence or absence of metabolites that cause conformational changes in enzymes
Activating or inhibiting the enzyme
Feedback inhibition occurs when the end product of a metabolic pathway inhibits the first enzyme in the pathway
Enzyme regulation
Activity of enzymes may be controlled by presence or absence of a
Phosphate group
Drives energetically unfavorable reactions
Formed primarily in mitochondria
Most free energy in resides in two phosphoanhydride (highenergy) bonds between the three phosphate groups.
ATP
