Biology Chapter 6 Energy and Metabolism

The 2 states of energy

Kinetic, potential

What provides energy for all living organisms?

The Sun

Oxidation

The loss of an electron in a chemical reaction

Reduction

The gaining of an electron in a chemical reaction

First Law of Thermodynamics

Energy cannot be created or destroyed

Second Law of Thermodynamics

Some energy is lost as entropy increases.

Usually heat

Disorder is always increasing

Free energy

The energy available to do work in any system

Equation for free energy

G=H-TS

Free energy=Enthalpy-Temperature*Entropy

Enthalpy

The energy contained in a molecule's bonds

Endergonic

A reaction that requires energy

G is +

Endergonic

A reaction that requires energy

G is -

Spontaneous but not instantaneous

Releases free energy

Activation energy

The energy required for a reaction to initiate

What kind of enzymes are there? (2)

Protein or RNA

Substrate

The molecule(s) that use enzymes for catalysis

Active site

The opening in an enzyme where the substrate binds to

Enzyme substrate complex

The enzyme as the substrate is bound to it

Multienzyme complex

A sequence of enzymes that catalyze a sequence of reactions

Advantages of multienzyme complexes

Product of one reaction can move right into the next reaction

Side reactions are avoided

All reactions can be controlled as a unit

Enzyme inhibitor

A substance that binds to an enzyme to reduce its activity

Enzyme activator

A substance that increases an enzyme's activity

Competitive inhibitor

Bind to the active site of an enzyme to reduce its activity

Noncompetitive inhibitor

Changes the shape of the enzyme without binding to the active site

Allosteric inhibitor

Reduces enzyme activity by binding to the allosteric (secondary) site

Allosteric site

The on/off switch for an enzyme

Enzyme cofactors

Chemical components that aid enzyme function

Coenzymes

A cofactor that is a non protein organic molecule

Metabolism

The chemical reactions carried out by an organism

Anabolism

Building molecules by expending energy

Catabolism

Break down molecules and harvest energy

Biochemical pathways

Product of one reaction becomes the substrate for the next reaction

Feedback inhibition

Last product binds to the first enzyme in the process

How do enzymes lower activation energy

Thy stress the bonds in the substrate

Electron carriers (4)

Cytochrome mb

Quinomes mb

NADH mobile

FADH2 mobile