Energy, Catalysis and Biosynthesis Flashcards
Second Law of Thermodynamics
Systems will change spontaneously toward arrangements with greater entropy. Therefore, the degree of disorder (entropy) will always increase over time.
What is entropy?
The dispersal of energy
A campfire is an example of entropy. The solid wood burns and becomes ash, smoke and gases, all of which spread energy outwards more easily than the solid fuel.
Why is entropy always increasing?
Changes towards ‘disorder’ are overwhelmingly more likely than those towards ‘order’.
Example: Releasing Heat
Everything done has an amount of inefficiency so energy gets loss in some way, increasing disorder to the system.
If creating and growing requires ‘order’ in cells, how is the second law of thermodynamics obeyed?
In the process of cells growing and creating chemical functions, some energy is inevitably loss in the form of heat, increasing entropy
What is the first law of thermodynamics?
Energy cannot be created or destroyed. They can be converted from one form to another.
How do cells manage to create and maintain order despite ever increasing entropy?
Cells use a tremendous amount of energy to create and maintain order. Cells get their energy from light and food and convert them to a usable energy.
Free Energy
Energy that can be harnessed to do work or drive chemical reactions
What determines whether a chemical reaction can occur?
Delta G
Reactions that create disorder by decreasing the amount of free energy of the system because they are energetically favorable. Basically, a reaction can only occur if delta g is negative.
Energetically favorable reactions have a negative Delta G
What does it mean for change in free energy to be zero
The reaction is at equilibrium, meaning the rate of the forward reaction equals the rate of the reverse reaction. All reactions tend to proceed towards equilibrium.
Note: the concentration of reactant and product may NOT be equal.
How does delta g naught relate to K
It is directly proportional. If K is bigger, delta g naught is more negative, thus there is more free energy and more favorable.
What is a coupled reaction?
A reaction where the the free energy of a favorable transformation and a unfavorable transformation join into a new reaction to drive unfavorable reaction.
Coupled Reaction- Activated Carrier
Activated Carrier: ATP
Glucose + Fructose -> Sucrose = 23 kj/mol (unfavorable)
but when we add ATP
Glucose - ATP + Fructose -> Sucrose + P = -7.5 kj/mol (favorable)
What is an activated carrier? What is it use for?
Small organic molecules that contain one or more energy-rich covalent bonds. In a cell setting, cells used activated carrier to carry out unfavorable reaction.
What is a catabolic pathway?
Catabolic pathways are those that generate energy by breaking down larger molecules.
Energy is released when breaking down larger molecules
What is an anabolic pathway?
Anabolic pathways are those that require energy to synthesize larger molecules. Anabolic pathway used the energy generated from catabolic pathway to synthesize larger molecules.
Anabolic pathway is powered by catabolic pathway.
How does catabolic pathway contribute to creating order in cell?
The catabolic pathway break down foodstuff into smaller molecules, thereby generating
both a useful form of energy for the cell and some of the small molecules
that the cell needs as building blocks.
How does anabolic pathway contribute to order in the cell?
Anabolic pathway use the generated energy (catabolic pathway produces energy when breaking down molecules ) to synthesize larger molecules.
What is oxidation?
Losing an electron for another compound to gain an electron (reduction)
What is reduction?
Gaining an electron
How does cell obtain energy by the oxidation of organic molecule?
Cellular Respiration
Cellular respiration is an oxidative process where glucose is being oxidized. This produces energy for the cells.
Hydrogenation
Hydrogenation: chemical reaction between a compound and H2.
Electron usually gets transfer with a proton. Therefore, an increase in the number of C–H bonds, in an organic molecule indicates a reduction
Dehydrogenation
Chemical reaction that involves the removal of hydrogen, usually from an organic molecule.
Electron usually gets transfer with a proton. Therefore, a decrease in the number of C–H bonds, in an organic molecule indicates an oxidation.
What are enzymes?
Proteins that binds onto substrate, responsible for its (nearly all) chemical transformation that occur in cell.
What is an activation energy?
The minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo chemical transformation or physical transport.