Class Notes (837,186)
Canada (510,155)
Biology (6,817)
Biology 1002B (1,346)
Lecture 4

Lecture 4.docx

3 Pages
Unlock Document

Biology 1002B
Denis Maxwell

Lecture 4: Energy and Enzymes 1. Isolated, closed and open systems.  Isolated system – Does not exchange matter or energy with its surroundings E.g. thermos  Closed system – Does not exchange energy but not with its surroundings E.g. green house, earth  Open system – Energy and matter can move freely between system and surroundings E.g. ocean 2. First law of thermodynamics  Energy transformed into another form or transferred to another place but not created or destroyed 3. Second law of thermodynamics  Energy transformations increase disorder 4. What is meant by the phrase "it takes energy to maintain low entropy" (section 4.1e)  The universe favours higher entropy  Life obeys the second law o Molecules, structures and living cells created order from less order structures o Cells are an open system o Uses energy (food) to maintain order and give off heat (increase disorder) o Entropy of a system is allowed to decrease as long as entropy of universe as a whole increases 5. Potential, kinetic, chemical energy  Potential energy – energy possessed by virtue of its position relative to others  Kinetic Energy – mechanical energy that a body has by virtue of its motion  Chemical Energy – part of energy in a substance that can be released by a chemical reaction 6. Entropy, enthalpy (H), DH, exothermic, endothermic  Entropy o + ∆S = more disorder o - ∆S = less disorder  Enthalpy (potential energy) o + ∆H = endothermic (energy gained from surrounding, potential energy of products > reactants) o - ∆H = exothermic (potential energy of products < reactants – see graph) 7. Gibbs Free Energy, exergonic, endergonic, spontaneous reaction  + ∆G = endergonic o Not spontaneous  - ∆G = exergonic = spontaenous o Spontaneous reaction  Potential energy of products < reactants (exothermic) *tends to be spontaneous  Products are more disordered (increase in entropy) o Phase change from solid  liquid  gas  Endothermic process but positive entropy is large enough to make - ∆G  Entropy driven since more disorder of molecules 8. Catalyst, rate of reaction, energy of activation (EA), transition state, kinetic stability  Catalyst – substance that increases rate of chemical reaction without permanently changing itself  activation energy o amount of energy needed to overcome the barrier to get totransition state o where bonds start t
More Less

Related notes for Biology 1002B

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.