Most reactions within the cell have to occur once molecules have absorbed enough energy to become unstable. Once reactants reach the “transition state” they are able to form products but they need activation energy to reach this point, enzymes provide this activation energy. Enzymes aid reactions that would eventually occur, but they speed up the process.
How do Enzymes work?
An enzyme has only a specific shape that allows only certain reactants to fit into the enzyme. This shape or cut out is called the active site once the reactant(s) are inside the active site they enzyme is able to speed up their breaking apart and then release them as separate products. The enzyme either speeds up the process by allowing the optimal conditions (position Ph ect) for the reactions or by fitting into the active site it puts stress on the reactants decreasing their stability making it easier for them to react.
What is the difference between an Exergonic and endogonic reaction?
An exergonic reaction is also known as a spontaneous reaction it will just happen without the input of energy. It releases free energy that can be used for work or more reactions. These reactions start with a high energy potential and move to a lower more stable energy potential this is also know as it moving towards equilibrium. Endergonic reactions start with a lower potential energy and then as it absorbs energy it moves to a higher potential. These reactions take the free energy from their surroundings and essentially store it for a later exergonic reaction.
Facts:
-All chemical reactions within organisms are referred to as metabolism
- Most energy within the cell is produced by ATP (exergonic reaction)
- A substrate is what an enzyme is aiding in reaction
- If a cell reached metabolic equilibrium it would die the system keeps it from reaching equilibrium so the cycle of energy can continue
- Inhibitors prevent a substrate from bonding with the enzyme thus preventing enzymatic processes
This figure describes the process of ATP breaking down in order to produce energy for the cell. Since ATP is at an unstable energy level the original reaction occurs from the desire for energy equilibrium and so one of the phosphates breaks off forming ADP and an a single phosphate. The first reaction is exergonic and then the cell uses energy from other sources such as food intake or photosynthesis to take the ADP and by an endergonic reaction reform ATP. In this cycle the ATP→ADP + P→ATP so the energy is continually recycled within the cell.
Summary:
Energy is the ability to do work and all living organisms need energy to live energy is constantly being released and absorbed by chemical reactions within the cell also called metabolism. Metabolism follows pathways either catabolic (breaking down) or anabolic (building molecules). There are three types of energy kinetic (motion), Potential energy, or activation energy (energy needed to get kinetic energy going). There are two laws of thermodynamics: 1. Energy can’t be created or destroyed only transferred into a different form 2. Transfers of energy increase entropy.
Free energy is the energy able to do work in the cell and reactions move one of two ways either from high potential energy to low potential energy releasing free energy in the process or from stable potential energy to high potential energy essentially absorbing free energy and storing it. The cell needs to break down things with stored energy and enzymes aid in this process by bonding to the molecule and creating conditions optimal for it to react.
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