2.1.4 Enzymes – Enzyme action Flashcards
(15 cards)
Where can enzymes be found?
Extracellular enzymes are found and work outside of cells e.g. amylase and trypsin. Intracellular enzymes are found inside cells e.g. catalase.
What is the function of enzymes?
They control all the chemical reactions that happen in the body. They are catalysts and they are specific to certain substrates.
What does a catalyst do?
It speeds up a reaction without being altered or used up by the reaction.
What are enzymes made out of?
They are a polymer made of amino acids (they are proteins).
Describe the structure of enzymes
They are globular proteins with a very specific secondary and tertiary structure. Each one has a depression or cleft on the surface called the active site.
Why are enzymes described as specific?
Each active site is different so it can only catalyse one reaction (it can only bind with one type of substrate).
What is produced when an enzyme binds to a substrate?
An enzyme-substrate complex.
What is produced when an enzyme has catalysed a reaction but has not released the product?
An enzyme-product complex.
What are the two theories of enzyme action?
The lock and key hypothesis, and the induced fit hypothesis.
Describe the lock and key hypothesis
This hypothesis states that part of the substrate fits exactly into the active site like a lock and a key. Their shapes are complementary.
Describe the induced fit hypothesis
This hypothesis states that the shape of the enzyme changes slightly to hold the substrate in the enzyme substrate complex.
What happens in an anabolic enzyme reaction?
Two substrates bind together to make one product.
What happens in a catabolic enzyme reaction?
A substrate is broken down into multiple products.
What is activation energy?
Activation energy is the energy that a substrate must be provided with in a chemical reaction before it can change into a product.
What effect do enzymes have on activation energy?
Enzymes lower the activation energy needed for a reaction.
