Chemical Energy

Energy

1. Definition

2. “If two possible events could happen…”

3. What two types of energy does biology focus on?

4. Do events require energy? Do events release energy? Both?

1. Definition: The ability to cause change

2. “…the one that requires less energy is more likely to occur”

3. Thermal energy and kinetic energy

4. All events require energy, but only some events release energy.

Kinetic energy (definition)

Energy of motion (particles moving/vibrating)

Thermal energy

1. Definition

2. What is it measured in?

1. Definition: Energy of heat

2. Measured in calories

What is the relationship between kinetic and thermal energy?

When particles move (kinetic energy), they generate heat (thermal energy)

1. What action are atoms constantly doing?

2. What happens when atoms bond (what does the bond itself do?)

3. What do bonds between atoms store? What happens to that storage when you break a bond?

4. What happens to atoms when a bond between them is broken?

1. Vibrating/moving

2. The bond between atoms restricts their movement, acting as a coil.

3. Bonds between atoms store energy. If you break the bond, it releases that energy.

4. They fly away with kinetic energy, like a bow shooting an arrow.

Potential energy (definition and 2 examples)

Energy stored in an object that is not yet being utilized (such as energy being stored in bonds, or water waiting to be released behind a dam)

Do all bonds take an equal amount of energy to break?

No, they can be easier or harder to break and release their stored energy.

What three main things need to happen correctly in order for a chemical reaction to occur?

1. Collisions: Molecules have to physically collide and with enough kinetic energy

2. Position: Molecules must collide in a specific orientation

3. Available components: Some reactions need extra molecules, electrons/protons, or further components.

What two factors increase the chance of molecular collisions occurring?

1. High concentrations of molecules

2. Higher temperatures (increase kinetic energy)

Enzymes

1. Definition (in relation to reactions)

2. What do enzymes decrease?

3. Why are enzymes necessary?

4. What acts as an enzyme’s “on/off switch”?

1. Definition: Proteins that hold molecules in the right orientation for reactions to happen

2. Enzymes decrease activation energy (the minimum amount of energy needed for a reaction

3. Enzymes are necessary for cells to work at an efficient speed

4. The action of adding/removing a phosphate group turns an enzyme “on” or “off”.

Phosphorylation

The act of a phosphate group attaching to an enzyme

What must enzymes maintain in order to function?

Enzymes must maintain their tertiary and/or quaternary structure for functioning.

Reagent

A substance that participates in a chemical reaction

How selective are enzymes’ receptor/acceptor sites?

Very selective, but have a small degree of flexibility (modern medicine takes advantage of this)

What change can affect an enzyme’s functionality?

Genetic mutations, since enzymes are proteins.

Are enzymes reusable? Why or why not?

Yes, enzymes are reusable. They facilitate reactions but are not directly involved (their structure doesn’t change).

Do enzymes need to be replaced? Why or why not?

Enzymes do need to be replaced. Byproducts of the reactions they facilitate can damage them over time.