A: Metabolism is the totality of an organism's chemical reactions. It is an emergent property of life that arises from interactions between molecules within the orderly environment of the cell.
Q: What are the forms of energy?
A: There are kinetic energy, the energy of action or motion, potential energy, stored energy or the capacity to do work, and activation energy that is needed to convert potential energy into kinetic energy.
Q: What is an enzyme?
A: An enzyme is a macromolecule that acts as a catalyst, a chemical agent that speeds up a reaction without being consumed by the reaction.
1. An organism's metabolism transforms matter and energy, subject to the laws of thermodynamics.
2. The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously.
3. ATP powers cellular work by coupling exergonic reactions to endergonic reactions.
4. Enzymes speed up metabolic reactions by lowering energy barriers.
5. Regulation of enzyme activity helps control metabolism.
Figure 8.19
Inhibition of enzyme activity.
A normal binding is justr a normal binding where a substrate binds normally to the active site of an enzyme.
Competitive inhibition refers to when there is a competitive inhibitor that blocks the substrate from fitting in to the active site by mimicing, pretending to be the substitute, being in the place where the substitute should be.
Noncompetitive inhibition is what binds to the enzyme not where the active site is, but away, and still affects the substrate from completely fitting in the active site because the inhibitor alters the shape of the enzyme.
This chapter is about metabolism and it is the collection of chemical reactions that occur in an organism. Aided by enzymes, it follows intersecting pathways, which may be catabolic (breaking down molecules, releasing energy) or anabolic (building molecules, consuming energy).
Then there are free energy, ATP, enzymes and the activation energy, and the substrates and the active site. In this chapter, we can find that enzymes do a lot of work and that they are important. The enzymes make the reaction to happen faster by lowering the activation energy barrier and how they work in the active site, the catalytic cycle, is very important.
Key terms
Metabolism: an emergent property of life that arises from interactions between molecules within the orderly environment of the cell.
Bioenergetics: the study of how energy flows through living organisms.
Chemical energy: the term people use to refer to the potential energy available for release in a chemical reaction.
Thermodynamics: the study of the energy transformations that occur in a collection of matter.
Free energy: is the portion of a system’s energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell.
Exergonic reaction: An exergonic reaction proceeds with a net release of free energy.
Endergonic reaction: An endergonic reaction is one that absorbs free energy from its surroundings.
Active site: only restricted region of enzyme molecule actually binds to the substrate, this region, called the active site.
Competitive inhibitor: they reduce the productivity of enzymes by blocking substrates from entering active sites.
Noncompetitive inhibitor: they do not directly compete with the substrate to bind to the enzyme at the active site; instead they impede enzymatic reactions by binding to another part of the enzyme.
http://www.youtube.com/watch?v=2DRWqBld7XU&feature=related
No comments:
Post a Comment