Enzymes Flashcards
They are also known as helper protein molecules.
Enzymes
Enzymes are proteins that change the rate of a chemical reaction. Therefore, they are referred to as ___.
Biological catalysts
True or False: All chemical reactions in living organisms require enzymes to work.
TRUE
True or False: Each enzyme is the specific helper to a specific reaction.
TRUE
True or False: Enzymes are named for the reaction they help.
TRUE
Sucrase breaks down ___.
Sucrose
____ break down proteins.
Proteases
Lipases break down ___.
Lipids
True or False: DNA polymerase breaks down DNA.
FALSE. DNA polymerase builds DNA.
It is the region that binds substrates, cofactors, and prosthetic groups.
Active site
What does the active site contain that holds the substrate?
Residue
True or False: The active site of an enzyme has a specific shape due to the quaternary structure of protein.
FALSE. It has a specific shape due to the tertiary structure of protein.
What are the two divisions of the active site?
Binding site
Catalytic site
It is the substance at the beginning of the process on which an enzyme begins an action.
Substrate
When a substrate binds to an enzyme, it forms a/an ___.
Enzyme-substrate complex
Enzymes are a type of protein, therefore they are synthesized by what organelles?
Ribosomes
Information for the synthesis of enzymes is carried by the ___.
DNA
What are the two types of enzymes in terms of location in the cell?
Intracellular enzymes & extracellular enzymes
These enzymes are synthesized and retained in the cell for the use of the cell itself.
Intracellular enzymes
In which specific cell parts can intracellular enzymes be found?
Cytoplasm, nucleus, mitochondria, & chloroplast
True or False: Extracellular enzymes are synthesized outside of the cell to work externally.
FALSE. Extracellular enzymes are synthesized in the cell but secreted from the cell to work externally.
True or False: An enzyme is names according to the name of the substrate it catalyzes.
TRUE
Why do most enzymes end in “-ase” while some do not?
Some enzymes were named before a systematic way of naming enzymes was formed.
What are some examples of enzymes that were named before the formation of a systematic way of naming enzymes.
Pepsin, trypsin, renin
Hydrolase catalyzes what type of reaction?
Hydrolysis reaction
What enzyme catalyzes an oxidation reaction?
Oxidase
What suffix is used to recognize that a substance is that of an enzyme?
-Ase
In naming an enzyme, how is the prefix determined?
The type of reaction the enzyme catalyzes.
In naming an enzyme, what else is taken into consideration in addition to the type of reaction?
Identity of the substrate.
What reaction does glucose oxidase catalyze?
Glucose oxidation
What enzyme catalyzes the eliminating of hydrogen from lactate ion?
Lactate dehydrogenase
What is the organization that standardized the naming of enzymes?
International Union of Biochemistry
What are the two parts of naming an enzyme?
Name of the substrate for the enzyme
Type of reaction catalyzed by the enzyme
What is the product when lactase breaks down lactose?
Glucose and galactose
What is produced when maltase breaks down maltose?
Glucose
True or False: When cellulose is broken down by cellulase, glycogen is produced.
FALSE. Glucose is the product.
What is produced when lipids are broken down by lipase?
Glycerol and fatty acid
What disaccharide is produced when amylase breaks down starch?
Maltose
Proteases break down proteins, resulting in a product of ___.
Peptides and polypeptides
What are the 6 classifications of enzymes?
Oxidoreductases
Transferases
Hydrolases
Lyases
Isomerases
Ligases
In this reaction, electrons travel from one molecule to another.
Oxidation
It is the transfer of hydrogen or addition of oxygen.
Oxidation
What enzymes catalyze oxidation reactions?
Oxidoreductases
This classification of enzymes catalyze the transformation of a functional group from one molecule to another.
Transferases
True or False: Transferases transfer one group (other than hydrogen) from the substrate to the enzyme.
FALSE. They transfer one group from the substrate to another substrate.
It is a reaction where single bonds are broken down upon exposure to water.
Hydrolysis
What enzymes catalyze hydrolysis?
Hydrolases
Give examples of bonds that can be broken down by hydrolases.
Ester, ether, peptide, & glycosidic bonds
This classification of enzymes catalyze the breakdown of various chemical bonds by means other than hydrolysis & oxidation.
Lyases and isomerases
What do lyases and isomerases often form?
New double bonds or ring structures
These enzymes break bonds without adding water.
Lyases
These enzymes catalyze reactions involving a structural rearrangement of a molecule.
Isomerases
It is the combination of pairs of substrates.
Ligation
What enzymes catalyze ligation?
Ligases
What do hexokinases catalyze?
The interconversion of of glucose and ATP with glucose-6-phosphate and ADP
It is an inactive enzyme without its non-protein moiety.
Apoenzyme
It is an active enzyme with its non-protein component.
Holoenzyme
They are non-protein substances that associate with enzymes.
Cofactors
It is a non-protein chemical compound that is bound (either tightly or loosely) to an enzyme.
Cofactor
What process requires the presence of cofactors?
Catalysis
It is a non-protein component that is loosely bound to an apoenzyme.
Coenzyme
It is a non-protein component tightly bound to an apoenzyme.
Prosthetic group
True or False: Coenzymes are bound by covalent bonds, while prosthetic groups are bound by non-covalent bonds.
FALSE. Coenzymes = non-covalent bonds; prosthetic groups = covalent bonds
It is the first push to start a reaction.
Activation energy
True or False: All chemical reactions require activation energy.
TRUE
In most chemical reactions, what must be overcome for the reaction to occur?
Energy barrier
What is the risk of using heat in order to overcome the energy barrier?
The rise in temperature may kill the cell.
Aside from heat, what is the alternative to overcome the energy barrier?
Lowering the activation energy through the use of a catalyst
This theory states that the active site has a rigid shape, and only substrates with a matching shape can fit.
Fischer’s Template Theory (Lock and Key Model)
It states that the substrate is a key that fits the lock of the active site.
Fischer’s Template Theory (Lock and Key Model)
This model explain enzyme specificity and the loss of activity when enzymes denature.
Lock and Key Model
This theory states that the active site is flexible, not rigid.
Koshland’s Induced Fit Theory
It states that the shapes of the enzyme, active site, and substrate adjust to maximize the fit, which improves catalysis.
Koshland’s Induced Fit Theory
This theory has a greater range of substrate specificity.
Koshland’s Induced Fit Theory
