Biology: Chemistry in Biology: 12: Catalysts and Enzymes - Medical Animation
This animation may only be used in support of a single legal proceeding and for no other purpose. Read our License Agreement for details. To license this image for other purposes, click here.
Biology: Chemistry in Biology: 12: Catalysts and Enzymes - Medical Animation
MEDICAL ANIMATION TRANSCRIPT: Today, we're going to talk about catalysts and enzymes. To understand enzymes, we need to know that chemical reactions require energy to occur. Recall that chemical reactions break the chemical bonds in reactants and rearrange those bonds to make products. Let's look at an energy diagram to see how energy changes as a chemical reaction progresses. At the start of a reaction, the reactants will have some amount of energy. If the products end up with more energy than the reactants had at the beginning, then this means the reaction absorbed energy from the environment. This is called an endothermic reaction. However, if the products end up with less energy than the reactants, then this means the reaction released energy. This is called an exothermic reaction. Either way, notice the peak in the energy hill just before the products begin to form. This peak represents the minimum energy the reactants required for the reaction to take place. The reactants need this energy to break their chemical bonds so that different bonds can be formed to make new products. This minimum amount of energy required for a reaction to take place is called activation energy. If the activation energy isn't reached, no reaction takes place. Sometimes, scientists need to make a reaction happen faster. If you want to speed up a reaction, you could increase the energy of the reactants by increasing their temperature, or you could add something called a catalyst. A catalyst is a substance that catalyzes or speeds up a chemical reaction without it being changed or used up by the reaction. Catalysts work by lowering the activation energy needed for the reaction to take place. By requiring less energy, catalysts make reactions happen faster and more efficiently because more of the reacting particles are likely to have sufficient energy or activation energy. And the higher the catalyst concentration, the faster the reaction takes place. Since catalysts aren't changed or used up by a reaction, they're available to catalyze more reactants. Chemical reactions are done in labs, but many chemical reactions also happen constantly inside your body. In living organisms, many reactions require catalysts. Biological catalysts are called enzymes. An enzyme is always made up of proteins. Proteins are one of the four types of organic compounds. We'll discuss them in more detail separately. Enzymes make life possible by lowering the amount of activation energy needed and, therefore, speed up reactions that would otherwise take too long. You need enzymes to stay alive. A reactant acted upon by an enzyme is called a substrate. Each enzyme has a unique active site that only a certain substrate can attach to, like a very specific puzzle piece. When attached, they form what is called an enzyme-substrate complex. This fit between an enzyme and substrate is so specific that it's often compared to a lock and key. When the substrate attaches to the enzyme, the enzyme lowers the activation energy needed to break the bonds in the substrate. Once the bonds break in the substrate, it separates into multiple components called products, which leave the active site. Afterward, the enzyme is still available to participate in another reaction with the same type of substrate. So, what factors affect how well an enzyme works? Well, enzymes work best around particular pH levels and certain temperatures, and the presence or absence of other chemicals can also impact their effectiveness. Not surprisingly, humans and other organisms have adapted to use enzymes that are most effective at the organism's natural temperature and pH values. To sum up, chemical reactions require energy to break the reactants' chemical bonds. The minimum amount of energy required for a reaction to happen is called the activation energy. Catalysts speed up reactions by lowering the activation energy. Catalysts aren't used up by chemical reactions. Biological catalysts are called enzymes. Enzymes are made of proteins. Enzymes act on reactants called substrates. Substrates bind to unique locations called active sites on enzymes. And factors that affect how well an enzyme works include pH, temperature, and other chemicals.
"Your firm is great to work with and, most importantly for me, you get the
job done on time and with the utmost professionalism. You should be proud of
all those you employ, from KJ to Ben B. I've been especially pleased over
the years with the work of Brian and Alice, both of whom seem to tolerate my
idiosycratic compulsion to edit, but I've not found a bad apple in the bunch
(and, as you know, I've used your firm a bunch!).
I look forward to our continued professional relationship."
Kenneth J. Allen Kenneth Allen & Associates
Valparaiso, IN
"It is with great enthusiasm that I recommend Medical Legal Art. We have
used their services for three years and always found their professionalism,
quality of work, and timely attention to detail to exceed our expectations.
We recently settled two complicated catastrophic injury cases. One medical
malpractice case involving a spinal abscess settled for 3.75 million and the
other involving injuries related to a motor vehicle accident settled for 6.9
million. We consider the artwork provided by MLA to have been invaluable in
helping us to successfully conclude these cases.
I highly recommend MLA to anyone seeking high quality, detailed medical
legal artwork."
E. Marcus Davis, Esq.
Davis Zipperman, Krischenbaum & Lotito
Atlanta, GA www.emarcusdavis.com
"Thank you very much for the great work on the medical exhibits. Our trial
resulted in a $16 million verdict for a 9 year old boy with catastrophic
injuries, and the medical illustrations definitely played key role in the
trial."
David Cutt
Brayton Purcell
Salt Lake City, UT
"Our practice involves medical negligence cases exclusively. We have six
attorneys and one physician on staff. We have used Medical Legal Art's
staff for every one of our cases over the past 12 years and have found their
services to be extraordinary. The transformation of medical records into
powerful graphic images has without fail been handled expertly,
expeditiously and effectively translating into superb results for our
clients, both in the courtroom and in settlement. Every case can benefit
from their excellent work and we unqualifiedly recommend their services.
They are the best!"
Chris Otorowski
Morrow and Otorowski
Bainbridge Island, Washington
www.medilaw.com
Medical Legal Art creates medical demonstrative evidence (medical
illustrations, drawings, pictures, graphics, charts, medical animations,
anatomical models, and interactive presentations) for use during legal
proceedings, including research, demand letters, client conferences,
depositions, arbitrations, mediations, settlement conferences, mock jury
trials and for use in the courtroom. We do not provide legal or medical
advice. If you have legal questions, you should find a lawyer with whom you
can discuss your case issues. If you have medical questions, you should seek the advice of a healthcare provider.