NRG and Enzymes

Definition: Ability to do work or cause change

Types of Energy

Potential and Kinetic Examples include: Chemical, Heat,

Mechanical, Solar/Radiant,

Electrical

Newton’s Laws of Thermodynamics

1st Law: Energy is neither created nor destroyed, it is conserved.

All energy is accounted for.All energy in universe is same, just

different forms.

Movement of Energy through an ecosystem

Trophic levels (Trophic levels are literally the levels of nourishment within an

ecological system, and hence describes how energy is transferred within food webs

and chains)

Organisms are Energy Organisms are Energy convertersconverters

Example of Trophic/Energy Pyramid

Another energy pyramid showing loss of available energy to heat energy

Newton’s Laws of Thermodynamics 2nd Law: "in all energy exchanges, if no energy enters or leaves the

system, the potential energy of the state will always be less than that of the initial state." This is also commonly referred to as entropy.

Example: A watchspring-driven watch will run until the potential energy in the spring is converted, and not again until energy is reapplied to the spring to rewind it.

Example: A car that has run out of gas will not run again until you walk 10 miles to a gas station and refuel the car. Once the potential energy locked in carbohydrates is converted into kinetic energy (energy in use or motion), the organism will get no more until energy is input again. In the process of energy transfer, some energy will dissipate as heat. Entropy is a measure of disorder: cells are NOT disordered and so have low entropy. The flow of energy maintains order and life. Entropy wins when organisms cease to take in energy and die.

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEner1.html

Entropy

Entropy is a measure of disorder. Entropy in the universe is increasing as more and more energy is converted to heat energy (energy that dissipates and can’t be trapped as potential energy).

Cells are NOT disordered and so have low entropy. The flow of energy maintains order and life.

Entropy wins when organisms cease to take in energy and die.

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEner1.html

Why study energy in regards to living organisms? Organisms need

energy to: Grow Find a

mate/Reproduce Find food Create a habitat

On the cellular level: Divide Repair Synthesize and

Catabolize Biomolecules

Chemical Reactions

Enzyme Characteristics

Decrease activation energy so chemical reactions can take place within cells.

Most are proteins (what are the monomers?)

Lock and key hypothesis Function within specific

environment (pH, salt concentration, temp.)

How enzymes work?

Lower Activation Energy

Active Site

How enzymes work?

How enzymes work?

Lock and Key Hypothesis Induced Fit Hypothesis

When things go wrong…change in enzyme shape

Denaturing Mutation in the genetic codeFor example: phenylketonuria is caused by an enzyme malfunction in the enzyme phenylalanine hydroxylase, which catalyses the first step in the degradation of phenylalanine. If this enzyme does not function, the resulting build-up of phenylalanine leads to mental retardation.