Biology II Chapters 6-8

Enzymes

Proteins that act as critical catalysts to speed up thousands of different reactions in cells

Chemical reaction

A process in which one or more substances are changed into other substances

How does a chemical reaction work?

Molecules attaching to each other to form larger molecules or them breaking apart to form two or more smaller molecules

Metabolism

Sum total of all chemical reactions that occur within an organism

What are two general factors that govern the fate of a chemical reaction?

Direction and rate

Energy

The ability to do work or cause change

Kinetic energy

Energy associated with movement

Potential energy

Energy associated with structure or location

Chemical potential energy

Energy stored in atoms and in the bonds between atoms

Heat

Transfer of kinetic energy from one object to another or from an energy source to an object

Electrical / ion gradient

The movement of charge or the separation of charges can provide energy

First law of thermodynamics

States that energy cannot be created or destroyed

Second law of thermodynamics

Any energy transfer or transformation from one form to another increases the degree of disorder of a system. This is called entropy.

Entropy

The degree of disorder in a system. When energy is transferred some becomes unusable. Especially the more transfer there is.

Enthalpy

The total energy of a system

Free energy

The amount of energy in a system that can do work

Exergonic reaction

Reactions that release free energy and occur spontaneously.

Endergonic reaction

Reactions that require an addition of free energy and do not proceed spontaneously

adenosine triphosphate (ATP)

Primary energy currency of cells, providing energy for various biological processes

Hydrolysis

Chemical breakdown of a compound due to a reaction with water

Hydrolysis removes a phosphate group from ATP to make what?

adenosine diphosphate (ADP)

What does it mean that ATP is a cyclic molecule?

Loses a phosphate group, becoming ADP, which can be phosphorylated back to ATP in an endergonic reaction. Essentially a single ATP can be reused.

How many cycles a day does the average ATP go through?

10,000 cycles

Catalyst

Speed up the rate of chemical reactions without being consumed by the reaction

Biological catalysts include

Enzymes and ribozymes

Activation energy

Initial input of energy needed to start a chemical reaction

Collision theory

Reactants must collide with enough energy and in the correct orientation to achieve transition state

What are are common ways to overcome activation energy?

Heat and catalysts