Biology 101 Unit 2

Anabolism

the BUILDING of molecules from smaller units, REQUIRING an input of energy (ATP) (endergonic)(+ ΔG)

Catabolism

the BREAKDOWN of molecules into smaller units, PRODUCING energy (ATP) (exergonic)(- ΔG) 

Metabolism

the building and breakdown of carbon sources to harness or release energy

Potential energy

energy that is not associated w movement but rather is stored

Kinetic energy

energy of motion

Chemical energy

a form of potential energy held in the chemical bonds between atoms (do strong or weak bonds have less potential energy?)

first law of thermodynamics

Energy cannot be created or destroyed, it can ONLY be transferred 

second law of thermodynamics

The amount of disorder in the universe, or entropy, is increased when energy is transformed.

Gibbs free energy ΔG

amount of energy in a system available to do work 

ΔS

change in entropy

Endergonic reactions

REQUIRE energy (nonspontaneous) (+ΔG) (anabolic) 

Exergonic reactions

RELEASE energy (spontaneous) (-ΔG) (catabolic) 

Enzymes

proteins that catalyze chemical reactions, highly specific for their substrate(reactant molecule that binds to enzyme), lower activation energy

activation energy (Ea)

is the energy required to reach the transition state, lower Ea = faster reaction

active site of an enzyme

where the substrate binds and the reaction is catalyzed 

inhibitors

DECREASE enzyme activity and can be reversible or irreversible 

Activators

INCREASE the activity of enzymes 

allosteric enzymes

activated or inhibited by a molecule binding to a site other than the active site 

negative feedback

when a later product inhibits an earlier step 

cellular respiration (4 steps)

converts energy like glucose into energy ATP

oxidation

losing electrons, glucose is the reducing agen?

reduction

gaining electrons, oxygen is the oxidizing agent?

anaerobic

does not use/consumes oxygen

glycolysis

an anaerobic process, 3 phases, splits glucose into pyruvate

Preparatory phase (phase 1)

Glucose is phosphorylated during this phase, trapping it inside the cell and destabilizing it (glycolysis)

Cleavage phase (phase 2)

where fructose 1,6 bisphosphate is split into two molecules, 2 molecules of glyceraldehyde 3-phosphate proceed to the next phase (glycolysis)

Payoff phase (phase 3)

where high-energy carriers are produced, Net yield: 2 pyruvate, 2 NADH & 2 ATP (glycolysis)

Pyruvate Oxidation

In the presence of oxygen, pyruvate can be further broken down to release more energy, Pyruvate is oxidized to acetyl Co-A in the matric of the mitochondria 

Citric acid cycle

completes the oxidation of glucose into carbon dioxide, Also referred to as the Krebs cycle or TCA cycle, 3NADH, and 1 ATP made 

electron transport chain

located in inner membrane of mitochondria (oxidative phosphorlyation)

proton gradient

Protons flow down their concentration gradient and power ATP synthase to make ATP  (oxidative phosphorlyation)

ATP synthase

Potential energy from the proton gradient is converted to kinetic energy in ATP synthase (oxidative phosphorlyation)

fermentation in animals and bacteria

w/out oxygen, pyruvate cannot be reduced to acetyl CoA,  Instead, pyruvate is broken down via fermentation to produce lactic acid 

fermentation in plants and fungi

Without oxygen, pyruvate cannot be reduced to acetyl CoA. Instead, pyruvate is broken down via fermentation to produce ethanol