BIOL 112 Lecture Notes - Lecture 5: Chemical Bond, Protein Folding, Catabolism
15 Jun 2018
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ENERGY, ATP & ENZYMES
Metabolism can happen in two activities:
Anabolic – reactions that link simple molecules to make complex ones, require energy,
energy-storing
Catabolic – break down complex molecules into simple ones, release energy
Cells must constantly acquire energy from their environment
Energy Conversions:
- Potential energy due to position (brick up) → kinetic energy (brick fall) → heat
energy (brick floor)
- Bond Energies:
- Chemical bond energy in H2 and O2 → rapid molecular motions in H2O→ heat
energy
What drives E-Conversions?
- The drive to be evenly dispersed in the universe (e.g. hot coffee) until the
temperature is a tiny bit higher everywhere
- To go from low probability to high probability (e.g. swimmer in water)
- Entropy disorder increases; the dispersing energy is the driving force for energy
conversions [2nd law of Thermodynamics] (free energy before → free energy after
(change ())
1. How can a cell release free energy (drive a chemical reaction)?
- Breakdown the proteins in the cell, chew the individual amino acids which
increase the disorder within the cell which then disperses energy (entropy (
2. With a chemical reaction releasing heat which generates disorder/disperses
energy in the surroundings (
Total Free Energy: (H = enthalpy, T= temp, S = entropy, G= free E)
If G is negative, it is then dispersed/released energy (disorder in the universe). If it
is positive, energy is required
***Chemical reactions only occur when is negative – can’t when positive***
4 Types of Reactions:
1) Heat is released (- and disorder is increased; spontaneous, exergonic (most
catabolic reactions)
2) Heat is released, but disorder decreases ( e.g. protein folding,
spontaneous below a certain temp.
3) Heat is used, but disorder increases; spontaneous above a certain T (
e.g. dissolving NaCl
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BIOL 112 Full Course Notes
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Document Summary
Anabolic reactions that link simple molecules to make complex ones, require energy, energy-storing. Catabolic break down complex molecules into simple ones, release energy. Cells must constantly acquire energy from their environment. Potential energy due to position (brick up) kinetic energy (brick fall) heat energy (brick floor) Chemical bond energy in h2 and o2 rapid molecular motions in h2o heat energy. The drive to be evenly dispersed in the universe (e. g. hot coffee) until the temperature is a tiny bit higher everywhere. To go from low probability to high probability (e. g. swimmer in water) Breakdown the proteins in the cell, chew the individual amino acids which (change ( (cid:1833))) increase the disorder within the cell which then disperses energy (entropy ( (cid:1845) )) energy in the surroundings ( (cid:1834)) Total free energy: (cid:1833)= (cid:1834) (cid:1846) (cid:1845) (h = enthalpy, t= temp, s = entropy, g= free e) If g is negative, it is then dispersed/released energy (disorder in the universe).
