Enzyme Action - 1.7 Flashcards
What type of protein are enzymes?
Globular
What are enzymes?
Globular proteins that act as catalysts.
What do catalysts do?
Alter the rate of chemical reaction without undergoing permanent changes themselves. They can be reused repeatedly and are therefore effective in small amounts.
What is the activation energy?
The minimum amount of energy needed to activate a reaction.
How do enzymes work?
By lowering the activation energy.
Why are enzymes important in the human body?
Enzymes allow reactions to take place at a lower temperature than normal. This enables some metabolic processes to occur rapidly at the human body temperature of 37 degrees, which is relatively low in terms of chemical reactions. Without enzymes, these reactions would proceed too slowly to sustain life as we know it.
What is the structure of enzymes?
Enzymes have a specific 3D shape that is the result fo their sequence of amino acids. There is one main part of an enzyme, known as the active site.
What is the active site of an enzyme?
A specific region of the enzyme is functional, this is known as the active site. The active site is made up of a relatively small number of amino acids. The active site forms a small depression within the much larger enzyme molecule.
What is the name given to the molecule that the enzyme acts upon?
The substrate.
How does the substrate react with the enzyme?
The substrate fits neatly into the active site and forms an enzyme-substrate complex. The substrate molecule is held within the active site by bonds that temporarily form between certain amino acids of the active site and groups on the substrate molecule.
What does the induced fit model propose?
The active site forms as the enzyme and substrate interact.
How does the induced fit model work?
The proximity of the substrate leads ti a change in the enzyme that forms the functional active site. In other words, the enzyme is flexible and can mould itself around the substrate.
What is the lock and key model of enzyme action?
The shape of the substrate (key) exactly fits the active site (lock).
What Is one limitation of the lock and key model?
In this model, the enzyme is considered a rigid structure. However, scientists had observed that other molecules could bind to enzymes at sites other than the active site. In doing so, they altered the activity of the enzyme. This suggested that the enzyme’s shape was being altered by the binding molecule. In other words, the structure was not rigid but flexible.
