Energy
What is kinetic energy?
The energy of motion.
What is the transition state in a chemical reaction?
The high-energy, unstable stage that molecules pass through before products form.
What are enzymes made of?
Proteins, though some RNA molecules can also act as enzymes.
What is ATP?
Adenosine triphosphate, a molecule that stores and transfers energy in cells.
What is a regulatory site on an enzyme?
A site where molecules bind to turn the enzyme on or off, separate from the active site.
What is potential energy?
The stored energy in an object or molecule due to its position or structure.
What is the difference between endergonic and exergonic reactions?
Endergonic reactions absorb energy, while exergonic reactions release energy.
What is the relationship between an enzyme, its active site, and a substrate?
The substrate binds to the enzyme’s active site, where the reaction happens.
Why is ATP a high-energy molecule?
Its phosphate bonds release a lot of energy when broken.
How does allosteric regulation differ from competitive inhibition?
Allosteric regulation changes the enzyme’s shape, while competitive inhibition blocks the active site.
Which molecule has more potential energy: one with O-H bonds or C-H bonds?
A molecule with C-H bonds because these bonds store more chemical energy.
What is activation energy?
The energy required to start a chemical reaction.
How do enzymes lower activation energy?
By stabilizing the transition state, making it easier for the reaction to proceed.
What is phosphorylation?
The addition of a phosphate group to a molecule, often transferring energy.
What is feedback inhibition?
When the product of a pathway inhibits an earlier step to prevent overproduction.
Why do molecules with C-H bonds store more energy than O-H bonds?
C-H bonds are less polar, so breaking them releases more usable energy.
Why do some reactions need energy input to proceed?
Because they are endergonic and require energy to overcome the activation energy barrier.
What’s the difference between competitive and non-competitive inhibitors?
Competitive inhibitors block the active site, while non-competitive inhibitors bind elsewhere, changing the enzyme's shape.
How does ATP change protein shape?
ATP transfers a phosphate group to the protein, causing it to change shape and perform work.
What does an allosteric activator do?
It binds to the enzyme and increases its activity.
How do organisms use stored potential energy?
They convert it into kinetic energy to power cellular processes like movement and transport.
How do coupled reactions drive biological processes?
An exergonic reaction (like breaking down ATP) provides energy to power an endergonic reaction.
What are cofactors and coenzymes?
Non-protein molecules that help enzymes function. Cofactors are usually metal ions, and coenzymes are organic molecules like vitamins.
How is ATP regenerated?
By adding a phosphate group to ADP using energy from cellular respiration.
How do pH and temperature affect enzymes?
They can change the enzyme’s shape, either increasing or decreasing activity.