Section 1 - Enzymes Flashcards
In a living cell, thousands of ________________ reactions take place every second. The sum of these reactions is called ___________. A single chain of these reactions is called a __________ __________.
biochemical, metabolism, metabolic pathway
What are enzymes?
Enzymes are biological catalysts
What do enzymes do?
They increase the rate (speed) of reactions. Enzymes reduce the activation energy.
Most reactions require an input of energy to get them going. What is this input energy called?
Activation energy
What type of proteins are enzymes?
Globular proteins
What determines how an enzyme works?
The order of amino acids in an enzyme determines its structure, and so how it works
What two things can enzymes be involved in?
- Breaking down molecules
- Building molecules
Give an example of how enzymes can be used to break down molecules
Digestive enzymes - important in the digestive system, where they help to break down food into smaller molecules, e.g. carbohydrates break down carbohydrates
Give an example of how enzymes are used to build molecules
Enzymes involved in DNA replication help to build molecules, e.g. DNA polymerase
What is a substance that’s acted upon by an enzyme called?
Substrate
What is the active site?
The active site is a region on the surface of the enzyme molecule where a substrate molecule can attach itself, its where the catalysed reaction takes place.
The shape of the substrate molecule and the shape of the active site are _______________.
complementary
What happens almost as soon as the enzyme-substrate complex has formed?
The products of the reaction are released and the enzyme is ready to accept another substrate molecule.
Why does each enzyme only catalyse one specific reaction?
Only one substrate will be the correct shape to fit
Describe how an enzyme becomes denatured
At high temperatures the atoms of the enzyme molecule vibrate more rapidly and break the weak bonds that hold the tertiary structure together.
