Biology 1202B Lecture Notes - Cellular Respiration, Electron Donor, Endergonic Reaction

162 views3 pages
Published on 19 Apr 2013
Study of energy in living systems and the organisms that utilize it
Potential Energy – energy that matter occupies because of its position
Kinetic Energy – energy in the process of doing work (energy of motion)
Isolated – no energy/matter is transferred between system and surrounding
Closed – energy can be transferred but matter cannot
Open – both energy and matter can be exchanged with environment
Laws of Thermodynamics
First: Energy cannot be created or destroyed, only converted to other forms
oAmount of energy in the universe always remains constant
Second: All energy transformations are inefficient because every reaction result in
an increase in entropy and the loss of unstable energy as heat
oEntropy – amount of disorder in a system
Biological Work
Entropy – energy that is no longer available to perform useful work (quality of heat
flowing between two bodies) nature tends to move from order to disorder in
isolated systems
Free Energy – part of a system’s total energy that can perform work when temp is
constant (G)
oChange in free energy (from one state to another): ΔG = ΔH -TΔS
Types of Reactions
Endergonic – nonspontaneous/requires a net input of energy (ΔG > 0) e.g.
Exergonic – spontaneous/releases energy (ΔG < 0) e.g. cellular respiration
Coupled Reactions – use exergonic processes to drive endergonic ones (overcome
energy barrier)
Redox Reactions – involve the transfer of one more electrons from one reactant to
oElectron donor = reducing agent, electron acceptor = oxidizing agent
oPhotosynthesis – reduction of CO2 into sugars + oxidation of H2O into O2
oRespiration (reverse reaction) – oxidizes sugars to produce CO2 and O2
Cellular Metabolism
Definition – sum of total chemical activity of all cells (2 types)
Anabolic –consumes energy to build complicated molecules from simpler ones
Catabolic – releases energy by breaking down complex molecules into simpler
ones (respiration)
Anabolic (synthesis) + catabolic (breakdown) = metabolism
Biological Organic Molecules (composed of subunits/building blocks)
Monomers combine to make polymers (large organic molecules are called
Dehydration Synthesis – combining/exchange reaction with removal of H2O
(reverse = hydrolysis)
oExergonic hydrolysis of ATP s coupled with the endergonic process of
transferring a phosphate group to another molecule (ATP + H2O = ADP + P)
Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.