Biology 1 Chapter 8 (Lecture) Flashcards
Cellular Respiration
The process of extracting energy stored in sugars and other fuels.
Metabolism
The totality of an organism’s chemical reactions.
Metabolic Pathways
A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule in to simpler compounds.
Catabolic Pathways
(BREAKDOWN) Breakdown pathways. There is a release of energy by breaking down complex molecules to simpler compounds (e.g. cellular respiration)
Anabolic Pathways
(BUILD UP) Consume energy to build complicated molecules from simpler ones; these are sometimes called biosynthetic pathways. An example is the synthesis of protein from amino acids.
Energy
The capacity to cause change; a rearrangment of a collection of matter.
Kinetic Energy
The energy associated with relative motion of objects.
Potential Energy
Energy matter possesses because of its location or structure (e.g. water behind a dam).
Heat
A form of thermal energy. It is the kinetic energy associated with random movement of atoms or molecules.
Chemical Energy
Potential energy available for release in chemical reaction.
Thermodynamics
The study of energy transformations that occur in a collection of matter.
The first law of thermodynamics states…
That energy can be Transferred or Transformed, but it cannot be Created or Destroyed.
The second law of thermodynamics states that…
Due to a loss of usable energy during energy transfer, that things in the universe tend to go toward Entropy whcih is randomness or disorder.
Exergonic Reaction
Proceeds with a net release of energy. These are reactions that occur spontaneously. (-DELTA G)
Endergonic Reaction
Is one that absorbs free energy from its surroundings. These reactions are nonspontaneous. Energy is required to drive the reaction. (+DELTA G)
A cell does three main kinds of work:
- Chemical Work
- Transport Work
- Mechanical Work
Chemical Work
Pushing reactions which would otherwise occur spontaneously (synthesis of polymers from monomers)
Transport Work
Pumping of substances across membranes against the direction of spontaneous movement.
Mechanical Work
E.G. the beating of cilia or the contraction of a muscle cell
Energy Coupling
The use of an exergonic process to drive an endergonic one.
ATP
Adenosine Triphosphate
It contains the sugar Ribose, the nitrogenous base Adenine and a chain of 3 Phosphate groups bonded to it.
Bonds between phosphate groups of ATP can be…
Hydrolized by adding water. Energy is released when this happens.
Coupling
When two reactions can be coupled so that overall, the coupled reactions are exergonic. It involves the transfer of a phosphate group from ATP to some other molecule. The recipient of the phosphate group is said to be Phosphorylated.
ATP Cycle
The shuttling of inorganic phosphate and energy
Enzymes
Macromolecules (proteins) that acts as a catalyst.
Catalyst
A chemical agent that speeds up a reaction without being consumed by the reaction itself.
Activation Energy
The initial investment of energy for starting a reaction. The energy required to contort the reactant molecules so the bonds can break.
An enzyme catalyzes a reaction by…
Lowering the activation energy enabling the reactant molecules to absorb enough energy to reach transition state even at a moderate temperature.
Enzymes cannot make reactions occur that would not…
Normally occur. They just hasten those that would occur anyway.
Substrate
The reactant an enzyme acts on.
The enzyme binds to the substrate to form
An enzyme-substrate complex.
Active Site
A restricted region of an enzyme molecule where the enzyme molecule actually binds to the substrate.
How does the temperature effect enzyme activity?
Increases enzyme activity to a certain point.
How does pH effect enzyme activity?
Depends on enzyme
Cofactors
Nonprotein helpers many enzymes requires for catalytic activity.
Coenzyme
If the cofactor is an organic molecule
Two types of enzyme inhibitors
- Competitive Inhibitors
- Noncompetitive Inhibitors
Competitive Inhibitors
Mimic the substrate and reduces productivity of enzymes by blocking substrates from entering the active sites.
Noncompetitive Inhibitors
Impede enzymatic reactions by binding to another part of the enzyme. This causes the enzyme molecule to change shape in a way that the active site becomes less effective.
