Lecture 10: Intro to Metabolism, Redox Flashcards
Describe chemical work and give an example.
Chemical work: the set of life-sustaining chemical interactions within cells of living organisms
Ex. Metabolism
Catabolism: Big to Small. The breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism.
Anabolic: Small to Big.
Constructive metabolism; the synthesis in living organisms of more complex substances from simpler ones. This requires energy.
Describe transport work and give an example.
Transport work: Work to take up nutrients, eliminating waste, and maintaining ion balances. Energy input is needed because molecules and ions often must be transported across cell membranes against an electrochemical gradient.
Ex.
Active transport
Facilitated transport
Describe mechanical work and give an example.
Mechanical work:Work for cell motility and the movement of structures within cells, such as partitioning chromosomes during cell division.
Ex.
Chemotaxis
Movement
Discuss how energy is generated in a cell
- Energy comes from transfer of electrons in chemical reactions
- Oxidation-Reduction
(Redox) reactions
-Energy released from chemical reactions can be stored and used in unfavorable reactions
ATP is formed form energy made available during aerobic respiration, anaerobic respiration, fermentation, chemolithotrophy, and phototrophy. Its breakdown to ADP and phosphate (Pi) makes chemical , transport, and mechanical work possible.
Define metabolism
Metabolism: The set of life-sustaining chemical reactions within the cells of living organisms.
Define Free Energy (G)
Free Energy (G): Energy available to do work
- Chemical reactions in a cell have a change in energy (energy required or released for a chemical reaction to occur)
- ΔG : Change in free energy during a chemical reaction (standard conditions)
- ΔG= Free energy of formation of products – Free energy of formation of reactants
Define Reduction Potential
Reduction Potential: The tendency of a molecule to want to donate (lose) electrons
E0 is standard reduction potential
< 0, a good e- donator
> 0, a bad e- donator (but a good acceptor!)
- The change in E0 can tell you how much free energy is available in the redox reaction
- The larger the ΔE0 value, the more energy you get from the reaction
What are the molecules on the right side of the half reaction best at?
And what molecule is at the top right?
- Molecules on the right side of the half reaction are the reduced forms (can donate electrons)
- Glucose is the best electron donor
What are the molecules on the left side of the half reaction best at?
And what molecule is at the bottom left?
- Molecules on the left side of the half reaction are the oxidized forms (can accept electrons)
- O2 is the best electron acceptor
How are metabolism, free energy, and reduction potential all related?
Metabolism which are the set of life-sustaining chemical reactions within the cells make it so that free energy is available through ETC and the change in reduction potential can tell you how much free energy is available in the redox reaction.
Define a catabolic reaction.
- Catabolic: Energy releasing
- Reactants: big molecule
- Products: Synthesized small molecules plus energy
Define an anabolic reaction.
- Anabolic: Energy requiring
- Reactants: Synthesized small molecules plus energy
- Products: Big molecule
Define Precursor metabolites.
Precursor metabolites: small organic molecules that provide carbon skeletons needed for biosynthesis of important chemical building blocks (monomers) an example is amino acids (protein synthesis).
Define reducing power.
Reducing power: ready supply of electrons (usually NADPH)
Understand oxidation-reduction reactions Understand the half reactions on the tower (Fig. 11.10), how to write a full redox reaction, identify e- donors/acceptors, calculate change in reduction potential (refer to in class worksheet)
PRACTICE!!!
