Enzyme structure and function (article) | Khan Academy
enzymes. Enzymes, like other catalysts, speed up the rates of chemical reactions by lowering . Plot illustrating the mathematical relationship between enzyme. Enzymes as biological catalysts, activation energy, the active site, and environmental effects on enzyme activity. To catalyze a reaction, an enzyme will grab on (bind) to one or more reactant molecules. The part of the enzyme where the substrate binds is called the active site. Understanding the Relationship Between Enzyme. Structure . Historical Perspective on Enzyme Catalysis. Protein Test Set.
It teaches us how enzymes work and how they can be changed. It also includes illustrations, examples, and a brief quiz. Why We Need Enzymes When people complete seemingly routine life functions, such as eating, their bodies undergo chemical changes that are driven by enzymes.
Enzymes are specialized proteins that act as catalysts for chemical reactions, getting the reactions going. Catalysts speed up chemical reactions without themselves being changed. There are numerous enzymes within living organisms. Some of the more common ones found inside our bodies include amylase, protease, and lipase to name a few. Each of these performs a specific function. For example, amylase helps break down the carbohydrates in the food we eat, protease breaks down proteins, and lipase breaks down fats.
All enzymes are important and all work in similar ways. How Enzymes Work Enzymes help to speed chemical reactions by lowering activation energy, which is the energy required for a chemical reaction to occur. When enzymes are present, this energy requirement is lowered, allowing the reaction to occur more quickly. Let's have a look at an example of this: Enzyme Function This graphic has two lines showing the reaction rates with enzymes in blue and without enzymes in red.
The dotted line represents the activation energy needed for this reaction to occur. Notice how there is less required energy in the enzyme driven reaction. The enzyme allows the reaction to occur more quickly than the reaction without an enzyme. Enzymes are highly useful, however, their reaction rates can be altered by their surroundings.
Impacting Reaction Rate There are several factors that can influence the rate of enzyme reactions. The most common include changes to pH, temperature, or substrate concentration. The substrate is the compound an enzyme bonds with.
Enzymes and Life Processes (Introduction to Enzymes)
More on this later… All enzymes have an optimal pH they work best in. The pH scale runs from 1 - 14 and is a measure of how acidic or basic a substance is. For example, something with a pH value of 2 represents a strong acid, such as lemon juice. Conversely, a pH value of 13 represents a strong base, such as bleach.
Outside their optimal ranges, enzymes work less effectively. Most catalysts including enzymes work the same basic way, because most chemical reactions including biochemical ones work the same basic way.
As a good basic example, lets look at the nitric oxide reaction from the last section. What you have is the collision of two molecules of nitric oxide that results in the breakage of nitrogen-oxygen bonds and the creation of new nitrogen-nitrogen and oxygen-oxygen bonds.
Figure showing two molecules of nitric oxide gas colliding to form a molecule of nitrogen gas and a molecule of oxygen gas If we were to dump a whole bunch of nitric oxide molecules into a normal jar with no catalytic converterand we were able to get an extreme close-up of what was going on at the molecular level, we would see millions of N-O molecules spinning and tumbling in space, smashing into each other and ricocheting off the walls of the jar at incredible speeds.
Very, very few nitrogen or oxygen molecules would be created, whereas most ofthe nitric oxide molecules would just bounce off of each other. Why the nitric oxide molecules bounce off each other: You also know that if you try and align one pole of a magnet with the same pole of the other, the magnets will repel. Nitrogen and oxygen atoms are like magnets in this sense. Figure showing magnets attracting and repelling and a figure a nitrogen and oxygen atom attracting and repelling.
The first rule is that there is a mutual attraction between red magnets and blue magnets. This means that if you stick the north pole of a red magnet to the south pole of a blue magnet, they will stick together, just like you would expect with two magnets.
The second rule is that there is a stronger mutual attraction between magnets of the same color: What this means is that a red magnet will prefer to stick to another red magnet, and a blue magnet will prefer to stick to another blue magnet, if given the choice.
So those are the rules about how our magnets behave. If the poles of the colliding magnets are lined up in the correct way, so that the north pole of one red magnet is contacting the south pole of the other red magnet, with the same happening for the blue magnets, what would happen? But only if the alignment is correct!
Enzyme structure and function
Figure of nitrogen and oxygen atoms colliding then bonding. This magnet thought experiment is a good approximation of what happens with real-life molecules like nitric oxide. But the alignment is key--nothing will happen without it. This is where catalysts come in. They help with alignment.
Enzymes and the active site (article) | Khan Academy
The odds favor nothing happening. This is what happens with nitric oxide molecules in a jar, when no catalyst is present. Figure of nitric oxide molecules in a jar unable to correctly align. But now imagine that we add an extremely motivated and conscientious magic gnome to the inside of our jar, with the instructions that he is to grab a red-blue in each one of his hands, align them in the right way, and then smash them together.
Adding this helpful gnome assistant will increase the rate at which red-reds and blue-blues are made, because achieving the right alignment is no longer a matter of random chance. Figure of nitric oxide molecules in a jar correctly aligning in the presence of a catalyst. Catalysts are the real-life versions of our imaginary magic gnomes. A platinum screen sits inside a catalytic converter attracting nitric oxide molecules to it and aligning them in just the right way, so that when they collide, the N and O switch places, and nitrogen gas and oxygen gas are created.
Catalysts make reactions fast by aligning reactants so that successful reactions are more likely!
Enzymes are biological catalysts Enzymes are the catalysts involved in biological chemical reactions. Why enzymes are so important The big reason enzymes are important to life is because cellular energy is a precious resource. This increase in the total number of collisions per second would increase, just as a matter of probability, the number of correctly aligned collisions too.
Enzyme Rate of Reaction: Factors & Catalysts
So, in the end, shaking the jar harder much harder, perhaps would result in an increase in the speed of red-red and blue-blue production too, just like adding a gnome and keeping the shaking of the jar the same. Figure of nitric oxide molecules in a shaking jar correctly and incorrectly aligning.
By just shaking the jar harder, you choose to do the work yourself and forego the services of the gnome. You get the same end-result, but it requires more energy expenditure on your part. If you use the gnome, you get to save this energy for other purposes: Or what if you have lots of energy available, but you have to do a lot of work to obtain it? Or, maybe you have extra energy, but you want to spend it on doing other important things.
In any of these three cases, the added savings you get from using the gnome to do the work might make a world of difference. Pretty cool for a few minutes effort!