2.3 Exploring enzymes Flashcards
What are enzymes?
Enzymes are protein catalysts that speed up reactions within cells without being used up by the reactions themselves
What are the naturally*-occurring micro organisms enzymes?
Bacteria and yeasts
Why enzymes are used for baking, cheese-making and production of juice?
Because it improves their texture appearance, and nutritional value to give them desirable flavors and aromas.
What are enzymes composed of?
Are proteins
amino acids that arranged in tertiary or quaternary structures that have complex conformations (shapes)
How do enzymes function?
Enzymes can be used to join two molecules or break one molecule into two parts
What does maltase do?
hydrolyzes breaks down maltose into glucose
What does sucrase mean?
hydrolyzes breaks down sucrose into glucose and fructose monomers n
What are enzymes specific for?
Enzymes are specific to a particular substrate (reactant)
In order for a reaction to occur, the reactions have to overcome
the activation energy (Ea) barrier
What is the activation energy?
Is the amount of energy that must be available in order for a reaction to occur.
How does the structure of enzymes allow them to lower the activation energy of reactions and increase the speed chemical reaction?
Enzymes lower the activation energy required for the reaction to occur by attaching to the reactants and positioning them so that they are in the optimal orientation to break or make chemical bonds between them.
When reactants begin to interact with enzymes they are called
substrates
The enzyme and its attached substrate form a structured called
enzyme-substrate complex
What happens when the substrate begins to attach?
The active site changes shape slightly to hold on to the substrate
Enzymes decrease the energy of activation by
stretching and bending chemical bonds that need to break during the reaction.
Coenzymes work by:
moving molecules from one enzyme to another.
Many coenzymes are derived from
vitamins
The coenzyme NAD- IS A DERVITIVE OF
vitamin B3 (niacin)
What does pepsin do>
It breaks down proteins into smaller fragments called peptides so they can be broken down further in the small intestine
What is one critical enzyme in respiration?
cytochrome c oxidase
What does cytochrome c oxidase do?
Helps to combine the highly reactive waste oxygen molecules produced during this process with hydrogen to form water
The enzyme acetylcholinesterase breaks
acetylcholine which is a natural transmitter
In bread making amylase is used to break down
flour starch to simple sugars which are converted by yeasts to alcohol and carbon dioxide(which makes the bread rise)
What are some benefits of industry enzymes?
- Replaces synthetic chemical which lower the amount of waste energy to produce food product
- Pectinase is used to produce clear apple juice
- Provides specific action that allows very specialized food products to be produced efficiently
Advantages of Cellulosic Ethanol
Would not compete with food production since its produced from waste
Disadvantages of Cellulosic Ethanol
expensive because of process of extracting it
What does lipase enzymes do?
breaks down triglyceride into glycerol and fatty acids
Enzymes are regulated using the following methods:
- Enzyme inhibition: Competitive and non-competitive
- Feedback inhibition
Most enzymes with more than one subunit contain more than one active site called the
allosteric site
The allosteric site is a place on an enzyme:
that will not bind substrates that bind to the active site
that will bind to other specific molecules that will change the shape of the enzyme and influence its ability to be active or not.
The allosteric site is involved in turning the enzyme
“on” and “off”
What is a competitive enzyme>
If the enzyme activation or inhibition happens on an active site its classified as competitive.
What is a non competitive enzyme?
If the enzyme activation or inhibition happens as a result of changes on the allosteric site its classified as non-competitive
What is the structure of competitive inhibitors
are molecules that are so similar in shape to an enzyme substate that they can bind to active site and block the normal substrate binding
What is the function of competitive inhibitors
Once the inhibitor has attached to the active site the enzyme is unable to catalyze any reactions at that site
Allosteric (or non-competitive) activators and inhibitors are molecules that bind to the
allosteric site not the active site
Allosteric (or non-competitive) activators and inhibitors are molecules that bind to the
allosteric site not the active site
Enzymes can oscillate in shape between the “on” and “off” conformation.
They can be temporarily locked into the “on” or “off” conformation by interacting with other molecules called
allosteric activators and inhibitors
How is hydrogen peroxide (H2O2) produced?
product of some cell processes and since its toxic to cells it must be inactivated immediately
This breakdown of hydrogen peroxide equation is:
2H2O2 –< 2H2O + O2
which enzyme is invloved in the breaking down of hydrogen peroxide
catalse
