Intro to Metabolism 1 Flashcards
Metabolism
total of all chemical reactions occurring in cell
Catabolism
reactions that release usable energy (ATP)
breakdown complex, ordered molecules into simple, disordered molecules
Anabolism
reactions that require energy;
build complex, ordered molecules from simple disordered molecules
Compare anabolism to catabolism
They do the opposite things
Energy
Energy = capacity to do work
3 types of work
chemical
transport
mechanical
Chemical work
Requires energy to synthesize complex biological molecules from simpler precursors
Transport work
Requires energy to take up nutrients,
eliminate wastes
maintain ion balances
mechanical work
Requires energy for cell motility and the movement of structures within cells
(i.e., partitioning of chromosomes during cell division)
Thermodynamics
analyzes energy changes in a collection of matter (i.e., a cell or a plant) called a system
Focuses on energy differences between initial state and final state of a system
How many laws of thermodynamics
2
First law of thermodynamics
Energy can be neither created nor destroyed, but can be converted from one form to another
Second law of thermodynamics
Physical and chemical processes proceed in such a way that the randomness or disorder of the universe (the system and its surroundings) increases
How is the second law measured
entropy
what is entropy
measure of the randomness or disorder of a system
Free Energy Change
How much energy is available to do work?
How is free energy calculated? (G)
^G = ^H – T^S ^= change in
What is ^H stand for in free energy calculation
change in enthalpy (bond energy; heat energy)
Absorb heat = +^H vs. Release heat = -^H
What does T stand for in free energy calculation
T = “temperature in Kelvin (K)” (K = degree C + 273)
What does S stand for in free energy calculation
change in entropy (disorder)
If S is increasing
Increasing (requires input of E for less entropy (more ordered))
what is ^Go’
the standard free energy change Standard conditions (298K, 1 atm (pressure), at pH 7.0 (i.e., most living cells))
what if ^Go’ is positive
exergonic reaction (proceeds spontaneously) Provides energy to cell (with appropriate enzyme & pathway(s))
what if ^Go’ is negative
endergonic reaction (does not proceed spontaneously) Requires input of energy (with appropriate enzyme & pathway(s) to proceed)
What is free energy G measured in
Joule (J) = energy unit; 1000 J = 1kJ (kilojoule)
List of electron carriers
NAD+ (ox), NADH (red)
FAD (ox), FADH2 (red)
NADP+ (ox), NADPH (red)
List of oxidation electron carriers
they get reduced (add a H)
NAD+, FAD, NADP
List of Reduction electron carriers
they get oxidized (take off H and e)
NADH
FADH2
NADPH
What do you notice with redox electron carriers
End with Hyrdogen
A reduction reaction is one in
which a reactant in a chemical reaction gains one or more electrons (-).
So loses H+
higher energy
A reduction reaction is one in
which a reactant in a chemical reaction gains one or more electrons (-).
So loses H+, Lose oxygen
higher energy
An oxidation reaction is one in
see slide 7
an electron is removed (-)
so gains H+, Gain oxygen
lower energy
Dehydrogenation
Does molecule have more or less energy when it gains electrons
MORE
Oxidation-reduction reactions
LEO-GER; OIL-RIG
Leo= losing electrons oxidation
GER gaining electrons reduction
Oxidation is loss
reduction is gain
Strongest reductants
see slide 10
More negative E0’ = donate e-
electron tower
slide 10
e- “fall” down tower. Further e- “fall”, more energy released
electron tower postive
slide 10
More positive E0' = accept e- Strongest oxidants (accept e-)
