Enzymes Flashcards
What is an enzyme?
Biological catalyst that increases rate of reaction that remains unchanged when the reaction is complete
What is metabolism?
Metabolism is the sum of all chemical reactions that occur in living organisms.
What are the roles of enzymes in metabolism?
- The conversion of food molecules to energy to run cellular processes.
- The conversion of food molecules to building blocks for proteins, lipids, nucleic acids, and carbohydrates.
- The elimination of nitrogenous wastes.
What do metabolic reactions do?
Allow organisms to grow and reproduce, maintain their structures, and respond to their environments.
What are anabolic reactions?
A part of metabolism - anabolism. 1. Larger molecules are built up from smaller molecules (condensation). 2. Usually require energy.
What are catabolic reactions?
A part of metabolism - catabolism. 1. Larger molecules are broken down into their smaller subunits (hydrolysis). 2. Usually release energy.
What are chemical reactions of metabolism?
Organized into linear metabolic chains or cyclic metabolic pathways.
How do chemical reactions occur in nature?
- Do not occur spontaneously. 2. If they occur, the rate of reaction is very low.
how do enzymes allow metabolic reactions to occur?
- Rapidly. 2. At a constant rate. 3. Under physiological conditions.
What are intracellular enzymes?
Enzymes that catalyze reactions inside cells.
What are extracellular enzymes?
Enzymes that are secreted from cells and catalyze reactions outside cells.
What is the specificity of enzymes and what is the cause of this?
Enzymes have high specificity due to their active sites.
What is the active site?
- Made up of specific amino acids. 2. Consists of 2 parts: Binding region and Catalytic region.
How does the active site work?
- Binds to the substrate with hydrogen bonds, hydrophobic interactions, or ionic bonds. 2. Has a precise 3D shape that is complementary to the substrate. 3. An enzyme will catalyze only one reaction.
What is activation energy and what do enzymes do?
Activation energy is the amount of kinetic energy needed to start a chemical reaction. Enzymes lower the activation energy.
What is the mode of action for an enzyme?
The function of an enzyme primarily depends on its 3D shape. The active site brings the substrates into physical closeness and the correct orientation for the reaction to take place.
How are enzymes globular proteins?
Non-polar hydrophobic R groups point into the center of the molecule, while polar hydrophilic R groups are located on the outside.
How are each protein structure in the enzyme involved in specificity?
- Primary - Sequence of amino acids determines the active site. 2. Secondary - Alpha and Beta pleated sheets position R groups. 3. Tertiary - Folding orients R groups for bonding. 4. Quaternary - Links between polypeptide chains alter enzyme properties.
What does a chemical reaction need to proceed?
The reactant molecules need kinetic energy equal to or greater than the activation energy and an input of energy.
What do enzymes do to a chemical reaction?
- Lower the activation energy. 2. Causes improbable reactions to occur. 3. Increases the rate of plausible reactions.
What happens to an enzyme after use?
It is not consumed or altered by the reaction.
What is altered and not by an enzyme in a chemical reaction?
Reactant (substrate) energy and product energy remain the same; only activation energy is lowered by the enzyme.
Why do we need enzymes?
Chemical reactions in nature are normally too slow to maintain life.
What is the lock and key hypothesis?
The active site is a perfect fit for a specific substance.
