Video 1
Enzymes- a fun introduction
Hey professor, just the other day I saw the small man swallowed an entire steak bigger than the size of his head. And it got me to thinking how could he possible digest all that in just a few hours. Well, the steak is first chewed in the mouth into bits and pieces that falls into the stomach. You might already know that the stomach contains a powerful acid that can dissolve even metals. But what you do not know is that this acid is not what ultimately breaks down the steak. Now it is very tiny and special molecules called enzymes that do the job. Strangely these enzymes find the stomach acid a cozy place to work in. Wow, it is like small piranhas finishing up a whale in a sea of acids, imagine what can I do with that. Well it doesn’t work that way. What do you mean it doesn’t work that way I know you were going to say that, to find out you need to know what exactly enzymes are and how they work. Whenever you are ready, click next to continue.
What are enzymes? They are proteins that speed up chemical reactions, without them reactions can still occur but they would be too slow to support life. There are many different types of enzymes, and they come in all manners of shapes and sizes. For example, what you call the piranha enzyme, it is actually Pepsin. It is only found in the stomach and digest proteins. In your mouth, there is amylase which break down starch. In your cells alone, there are hundreds of enzymes that control your cells activity and defend from the invasions by microbes like bacteria and viruses. Though enzymes can appear very different, they all share a few characteristics in common. Let’s now take look at what these are.
No.1 each enzyme has an active site.
This is the groove in the enzyme where the molecules they act on, called substrate, are captured and made undergo a reaction. The substrates are either broken apart or combined together to form products. For instance, starch found in the bread that you eat is digested to form simple sugars called “glucose” that is then absorbed into the body. Glucose is used up as energy but when there is too much of it, special enzymes combine the glucose molecules together to form a giant molecule called glycogen which is then stored in liver and muscles for later use.
No.2 enzymes are very specific
Each enzyme can only bind to one type of substate. Let’s look at the case of the lipase enzyme which breaks down fats. Molecules like glucose and proteins cannot fit into the active site of lipase, only fats cells can bind to the active site because they have the right shape. This ability to act on just fat cells is very important for lipase. Lipase converts fats into energy, now imagine what would happen if lipase can also convert protein into neural chemicals for the brain to function well. If you no longer need the extra energy from your storage of fats, lipase would be deactivated, but this means the lipase can no longer produce precious neural chemicals for your brain. In other words, when you stop burning fats, you end up damaging your brain. To prevent such freak scenarios from happening in your body, enzymes must only act on one type of molecule.
No.3 enzymes are recycled
Enzymes are not altered by the reactions they speed up. Immediately after they finish one reaction they can act on a new substrate. This way, only a small amount of enzymes is needed to speed up thousands of reactions.
Video 2
How to speed up chemical reactions (and get a date)
Meet our chemist Hurry. She has chemical reaction that needs to occur more quickly. Our chemist has process that are disposal and how can help speed up the reactions? And she knows five ways, and to remember them she thinks back to her days as a high school student. On the day she gets a date for the dance, Hurry was at high school studying between classes. She lost track of time and was going to be late to class. And beknows to her, Harold, who is just around on the corner and running late too, they both sprint to class and as it happened, to sprint directly into one another. Now this is no small collision, they run squarely into one another in such a way he knocked books right out of her hand. “I’m sorry”, he said, “let me help you with your books”. He kindly helped her recollect her belongings and politely offered to walk her to the class. You’ll never guess who went together to the dance later that year. Yep, those two, so as we can see from this example the key to get a date for a dance is to collide with someone and knock the books out of their hands. And probably you are already aware that not all collisions lead to the date for the dance, thankfully.
The collisions must have two important characteristics. One, correct orientation that allows books to be knocked from one’s hands and two enough energy that knock the books out. Surely after, since then Hurry decided to tell me, her chemistry teacher all about it. I noticed some interesting parallels between her story and chemical reaction rates, which happened to be what she was studying in the hallway at the date of collision. Together, we decided to set out on two missions. Hurry wanted to help all chemistry students and chemists to remember how to speed up the rate of chemical reactions, and I, being a nice guy that I am, decided to make my mission to help create educational environments, in which more book dropping collisions can take place to increase future chemist chances of getting a date for dance.
In order to facilitate this improved dance-date-getting process, I propose five changes to all schools that parallel Hurry’s five ways to increase chemical reaction rates. First I propose we shrink the size of the hallways, this will make it more difficult to safely navigate in the hallways and will cause more collisions than the larger hallways. And by increasing the number of collisions we increase the likelihood that some of those collisions will have the correct alignments and enough energy to create a date to the dance. Now chemically speaking, this is equivalent to lowing the volume of a reaction thus lower the reaction mixture. And doing so, the individual particles are close together, and more collisions will occur. More collisions means the greater likelihood to collisions with appropriate energy and configuration will happen.
Second I propose increasing the overall population in the school. More students equals more collisions. By increasing the number of particles available for collision, we create an environment where more collisions can take place. Third, we must reduce the time allowed between classes. Hack, let’s just cut in half. In doing so students would need to move more quickly to get from one class to the next. This increasing velocity will help to make sure collisions have appropriate energy necessary to ensure book dropping. This is analogous to increasing the temperature of the reaction mixture. Higher temperature means particles are moving faster. Faster moving particles means more energy and a greater likelihood of reaction-causing collision. Fourth, students must stop traveling in packs, by traveling in packs, those students on the outside of the pack insolate those in the middle for undergoing in the collisions. By splitting up, each student has more area exposed that is available for a collision. When particles travel in packs, the surface area is very small and only the outside particles can collide. However, by breaking up the clumps into individual particles, the total surface area is increased and each particle has an exposed surface that can react.
Fifth and finally we hire a matchmaker. Is this colliding and book dropping too violent? Is there an easier way to get a date that requires less initial energy? And a matchmaker will help with this. The matchmaker makes it easier for a couple to get together by coordinating the match. Our matchmaker is like a catalyst. chemical catalysts function by lower the activation energy, in other words by lowering the energy required to start reaction. They do this by bringing two particles together and orienting them correctly in space so the two can meet in correct configuration and allow a reaction to take place.
So, to sum up, if a future chemist wants a date for a dance, he must collide with another person and knock the book out of her hands. And if a chemist wants to make a chemical reaction occur, the particles must collide in the correct orientation with appropriate amount of energy. And both of these processes can be accelerated in the five methods as described.
2026 biochemistry chapter 6 enzymes part 1.pdf
