Level 2 Bio: Enzymes Flashcards
What is an enzyme
Enzymes are a type of protein. They are long complex strands of amino acids. They are biological catalysts: that lower the activation energy of a reaction/speed up reactions.
They are not part of the reaction, they facilitate the reaction. (With protein synthesis there are enzymes that catalyze the process to make enzymes (proteins))
There are lots of different types of enzymes that are specific to the type of reaction.
Cells would not be able to survive in our body without enzymes (the reactions in our body would take too long).
What are the parts of an enzyme
Active site, substrate
What do digestive enzymes do
Break complex insoluble food to small soluble molecules.
What does denatured mean
Enzymes become irreversibly damaged, loss of structure and shape - no active site.
What cause enzymes to denature?
pH if it’s too acidic or too basic
heat/temperature if it’s too high it will denature the enzymes.
What are the main points of enzymes
Enzymes are proteins!
Each chemical reaction in the body is controlled by a specific enzyme.
A reaction will only occur if that specific enzyme is present.
The molecule that an enzyme acts on is called the SUBSTRATE.
Most enzyme names end in -ase. This is usually added on to the name of the substrate it is acting on.
What does Lipase break down?
Lipase breaks down lipids (fat)
What enzyme breaks down fat?
Lipase
What does Maltase break down?
Maltase breaks down maltose
What enzyme breaks down maltose
Maltase
What does Lactase break down
Lactase breaks down lactose (milk, sugar)
What enzyme breaks down lactose
Lactase
What does Amylase break down
Amylase breaks down starch
What enzyme breaks down starch
Amylase
What are the factors that affect enzymes
Enzyme & substrate concentration.
Temperature: too low=slow reaction, too high= at a point will denature.
pH: Most work best at pH 7 (stomach digestive enzymes work in acid & intestinal enzymes work in alkaline.
What is it you need to know about the shape of an enzyme
The shape of an enzyme is unique to that enzyme they are like jigsaw puzzle pieces and will only fit one reaction. If the shape gets altered they don’t work.
What is a catabolic enzyme (catabolism)?
IMPORTANT!
Catabolic enzyme (catabolism this is where the substrate is broken down into smaller molecules. For example:
Digestion (breaking food down)
Respiration (glucose broken down into energy)
Co factors (co-enzymes) some enzymes have 2 parts to them:
The protein (enzyme)
And a co-factor (a metal or vitamin) these enzymes that need a cofactor can’t work without them.
Information to know about co-factors
Co factors (co-enzymes) some enzymes have 2 parts to them:
The protein (enzyme)
And a co-factor (a metal or vitamin) these enzymes that need a cofactor can’t work without them.
Definition of a Catalyst
Something that lowers the activation energy required for a reaction, which speeds up the reaction.
Definition of a Substrate
The chemicals that need to be made or broken.
Definition of a Product
The result of an enzyme’s reaction with a substrate.
Definition of Active Site
Part of the enzyme’s surfaces which the substrate binds to, it is where the substrate undergoes a reaction.
Describe the process of how enzymes produce new substances
A substrate bonds to the activation site on the enzyme, reactions occur where the enzyme changes shape which forces the substrate molecules to combine. The end product is then released, the enzyme returns to its usual shape.
What is meant by the activation energy of a reaction.
The amount of energy required for the reaction to be successful.
Describe how enzymes lower the activation energy
Enzymes are biological catalysts which influence the stability of the bonds in the reactants or they provide alternative reaction pathways which lowers the activation energy.
How does enzyme concentration affect enzyme activity
An increase in the enzyme concentration will mean an increase in the rate of reaction.
How does substrate concentration affect enzyme activity
As the substrate concentration increases the reaction rate will also increase until the saturation is reached.
How does temperature affect enzyme activity
A lower temperature will cause the reaction to be slower, when the enzyme is at it’s optimum temperature the reaction is faster, however if it gets too hot it will denature.
How does pH affect enzyme activity
At the optimum pH the reaction will be the most successful/faster most have an optimum pH of 7. If the pH is too low or high the reaction will not work so well.
What is a catabolic reaction
Catabolic reactions cause a single substrate molecule to break apart into separate products, as chemical bonds are broken. Examples are digestion and cellular respiration.
What is an anabolic reaction
Anabolic reactions combine 2 or more substrates to form a single product. Chemical bonds are formed, causing the substrate molecules to fuse together. Examples are protein synthesis and photosynthesis.
Distinguish between an anabolic reaction & a catabolic reaction
Anabolic reactions combine 2 or more substrates to form a single product, creating bonds. Whereas catabolic reactions break apart a single substrate into separate products and break bonds.
What does a cofactor do?
Help the enzyme to alter the shape of the enzyme to make it more reactive or to complete the active site. Cofactors can be metals (Na, K, Ca, Fe, Mg ions) or organic vitamins (called coenzymes).
Explain the role of enzyme cofactors in enzyme activity
They enable enzymes to change shape to fit substrates to make it more reactive or to complete the activation site.
Explain how inhibitors prevent substrate attachment
Inhibitors attach to the activation site of an enzyme stopping substrates from binding to the enzyme and therefore stopping the reaction from occurring.
What is an enzyme inhibitor?
These are objects that prevent a substrate from fitting into the enzyme. Some are reversible others are irreversible. Irreversible: These are poisons (heavy metal) they are permanent inhibitors & make the enzymes useless. Hg, Cd, Pb, & A’s are some. Reversible: These are inhibitors used to control the activity of an enzyme. Can be removed when the enzyme is needed.
What is the ‘lock & key’ model?
The Enzyme & substrate both have specific complementary geometric shapes that fit exactly into one another.
What is the ‘induced fit’ model?
The substrate doesn’t bind to a rigid active site, the active site moulds itself around the substrate for a more precise fit.
Definition of an enzyme
Enzymes are proteins that are biological catalysts and help to speed up chemical reactions by lowering the activation energy of a reaction.
