1.2: Thermodynamics Flashcards
What is a system?
Anything of interest to a scientist.
What is a biological system?
An open system (matter + E exchanged). Bio systems must acquire E/matter from surroundings and excrete waste.
What to make sure before going MORE into DETAIL (YOU MUST GO MORE INTO DETAIL)?
MASTER learning objectives (80%) before getting nitpicky with readings/prereadings + external sources.
What are the surroundings when working with systems?
EVERYTHING OUTSIDE of the system.
What is the waste of bacteria?
The unused products of their metabolic reactions.
What is Energy?
The ability to do work or cause change.
What is Work?
The change that requires energy. Cells do work through every cell processes since they all require energy.
Potential vs Kinetic Energy?
Potential E is energy due to position (prospection of change) while Kinetic E is energy due to motion (Ek IS the change vs chance of change). They can be converted to one another.
How does Ep explain electron energy levels?
Farther away electrons are attracted by center of nucleus but further away- greater distance to cover implies greater POTENTIAL E.
What determines the amount of potential energy within a molecule?
The arrangement of electrons in its chemical bonds (polar vs nonpolar). Nonpolar has higher Ep.
Whaat difference in electronegativity is considered non-polar?
0.4 or less.
What is a common source of cellular energy?
Electrochemical gradients (or concentration gradients). Nature wants stability and things to be equally shared (less Ep) so buildup of [chemical] over time will be broken and (like dam) high Ep will be converted to high Ek.
What is the principles of minimum potential energy?
A restatement of the second law. If particles are more spread out they are less likely to collide.
What is the first law of thermodynamics?
Energy is neither created or destroyed. Energy can change location and convert into different forms. ALL ENERGY that enters and leaves a system must come from the surroundings!
Where do molecules get potential energy from?
The energy stored in their chemical bonds.
What is Enthalpy?
The sum of all kinetic and potential energy.
What happens to enthalpy when work occurs?
Remember that work IS the change (work = change in Ek), so when work occurs, Ek changes, and when Ek changes, Enthalpy changes (deltaH).
What happens when heat is released from a system?
deltaH is negative (system losing heat/energy to surroundings). aka Exothermic reaction (ex; glucose + atp to glucose6p)
What happens when heat is absorbed by a system?
deltatH is positive (system gaining heat from surroundings). aka Endothermic reaction (ex; glucose to fructose) where the products have more total E (enthalpy) than the reactants (system absorbing E for reaction to go through).
What does deltaH determine?
The change in enthalpy- whether the products have more or less total energy than the reactants.
What is a spontaneous reaction?
A reaction that is able to occur under current conditions without external energy required. Has nothing to do with speed (doesn’t mean instantaneous). ex; oxidation of glucose is spontaneous because it occurs under regular physiological conditions. If a reaction is spontaneous in one direction than it is NON-SPONTANEOUS in the other direction.
What is a non-spontaneous reaction?
A reaction that cannot occur under current conditions.
Relationship between endothermic/exothermic and spontaneity of reaction?
THERE IS NO CORRELATION BETWEEN heat released and spontaneity of reaction.
What conditions does spontaneity consider?
Initial conditions of the collision/reaction, not conditions as they change over time.
BEST STUDY METHOD.
Go over brainscape study methods first + review couple days before and just do practice tests leading up to it.
What is entropy?
How dispersed the energy of the universe is. Energy iin all forms is considered, and the higher the [E], the lower the entropy (S).
What does deltaS measure?
The change in enthalpy, before or after a reaction. If energy has become more dispersed then deltaS is positive, if the concentration of energy increases then deltaS is negative.
Second law of thermodynamics
Total entropy must always increase. ANY energy transfer or conversion must increase the entropy of the universe.
What determines if a reaction is spontaneous?
Entropy. If a reaction increases entropy, it is spontaneous (deltaS+).
Enthalpy vs Entropy units?
Enthalpy is Kj/mol and entropy is kj/molxK.
How to understand concepts at a higher level?
Sit with them. Analyze them and MAKE AN ATTEMPT TO ANSWER YOUR OWN QUESTIONS before searching them up.
What to remember about total entropy?
It is the sum of a system and its surroundings (so system could lose entropy as long as surroundings is MORE POSITIVE). deltaS = deltaSsystem + deltaSsurroundings
What is free energy (G)?
Molecules have free energy, which is the measure of the energy in a system available to do work. For work (a change) to happen, enough E must be available to carry it out.
Free E reactants vs products?
The reactants must have more free energy than the products for the forward reaction to happen.
What is deltaG
The change in free energy, or the energy required to carry out a reaction. If deltaG is negative that means that E from reactants was used up in the reaction (spontaneous). Same units as enthalpy.
What are exergonic reactions?
Spontaneous reactions where deltaS is positive and deltaG is negative. ALL bio/cellular reactions are exergonic (have negative deltaG).
genic vs thermic?
All types of energy vs heat energy
How to relate deltaG and deltaS
deltaG = -T x deltaStotal (where K is T, watch units)
What are endergonic reactions?
Non-spontaneous reactions where deltaG is positive (products have more free E) and deltaS is negative which implies the enthalpy of the universe is decreasing.
How do endergonic reactions occur despite decreasing the entropy of the universe?
Endergonic reactions occur by being coupled with exergonic reactions. Read textbook. Buy labbook biol?
How to conceptualize/visualize free E?
It is consumed in a reaction.
How to relate deltaG to deltaH and deltaS ?
deltaG = deltaH - TdeltaSsystem (-heat of energy going into universe gives heat released by system). This is only at CONSTANT PRESSURE where enthalpy change of reaction is equal to heat leaving system.
When does chemical equilibrium occur?
When deltaG = 0 which implies that reactants and products have the same free energy and the forward/reverse reaction are occuring at the same rate. Our body excretes because cells would die if equilibrium was ever reached (how is E for sustenance processed?) so we keep as much reactants and little products as possible.
What happens at chemical equilibrium?
The reactants in a spontaneous reaction no longer have the free energy required to cause further change.
What is standard free energy change?
deltaG measured under standard conditions (temp, pressure, ect.). Controlled vs physiological conditions are different- a reaction may be spontaneous under (controlled) standard conditions but non-spontaneous under physiological conditions.
Relating deltaG to deltaGstandard?
deltaG = deltaGstandard + RT ( [product]/[reactants] )
What is metabolism?
The sum of all chemical reactions in a living cell is metabolism. Catabolism + Anabolism. Metabolic reactions are what lead to biochemical pathways such as the kreb cycle.
What is the breaking down of complex molecules such as eating carbohydrates and protein?
Catabolism breaks complex molecules into smaller ones to be used. Catabolism is exergonic in total since complex molecules have a lot of free energy.
What is the creation of complex molecules for the bodie’s use?
Anabolism puts energy/molecules from catabolism to use and creates the molecules the body needs to survive and grow. Anabolism is endergonic in total since the products of the process (complex molecules) have more free energy than the reactants (it is accoomplished through coupled exergonic reactions).
What is a connected reaction?
Connected reactions happen when the PRODUCT of a 1st reaction BECOMES REACTANT (aka substrate/agent of interest) of a 2nd reaction.
What is adenosine triphosphate (ATP)?
A Nucleotide Triphosphate (nitrogenous base tied to 5 carbon sugar and 3 phosphate groups) that has a lot of potential energy due to [negative charges around P]. REMEMBER nature hates [gradients] and wants E spread so work done with ATP by braking phosphate group through hydrolysis (adding h20 and filling bonds).
Besides ADP, what is created from the hydrolysis of ATP?
Pi or inorganic phosphate (phosphate group with 2 OH from water addition). Remember it’s not a hydrolysis but a PO4 or too much heat created.
What is a coupled reaction?
A reaction with 2 things happening at the same time in the same time.
Glycolysis?
Break down of glucose into simpler molecule. First reaction is a coupled reaction and connected to the second, while the second one is NOT a coupled reaction.
How to conceptualize gibbs equation?
Visualize particles colliding before/after + heat interactions. REMEMBER 2nd law states entropy of UNIVERSE is always increasing not necessarily system (heat spreads), and ALL FORMS of energy are considered in entropy.
