E1 Chapter 8: Enzymes and Proteins Flashcards
Exam 1
Protein that aids the selective acceleration of chemical reactions
Enzymatic proteins
Proteins that provide protection against diseases
Defensive proteins
Proteins that help to store amino acids
Storage Proteins
Proteins that aid in the transportation of a substance
Transport protein
A polymer of amino acids is called
A polypeptide
A biologically functional molecule made up of one or more polypeptides, each folded and coiled into a 3-D structure
Protein
An organic molecule with both an amino group and a carboxyl group
Amino acid
What is the carbon called at the center of an amino acid
An alpha carbon
The covalent bond between the carboxyl group on one amino acid and the amino group on another, forming a dehydration reaction
Peptide Bond
A linear chain of amino acids (the protein sequence of amino acids)
Primary protein structure
Regions stabilized by hydrogen bonds between atoms of the polypeptide backbone
Secondary Structures
A delicate coil held together by hydrogen bonding between every 4th amino acid
Alpha helix
Two or more segments of a polypeptide chain laying side-by-side
Beta Pleated Sheet
3-D shape stabilized by interaction of side chains
Tertiary Structures
Amino acids with hydrophobic side chains usually end up in clusters at the core
Hydrophobic interactions
Form where two cystine monomers, which have -SH groups on side, are brought close by folding
Disulfide bridges
The association of two or more peptides (the overall protein structure that results from the aggregation of polypeptide subunits)
Quaternary Structure
A process in which protein loses its shape due to the disruption of weak chemical bonds, becoming biologically inactive
Denaturation
A macromolecule that acts as a catalyst
Enzyme
A chemical agent that speeds up a reaction without being consumed by the reaction
Catalyst
Enzymes lower the _______________
Activation energy barrier
The amount of energy that reactants must absorb before a chemical reaction will start
Activation energy
The reaction on which an enzyme works
Substrate
A pocket or groove on the surface of an enzyme where catalyzation occurs
Active site
Are active sites specific or willing to bind many enzymes?
Very specific
The change in shape of the active site of an enzyme so it binds more snug to the substrate
Induced fit
Does the rate of an enzyme increase with increased or decreased temperature?
Increased
If we keep increasing the temperature, what will happen to an enzyme?
It will denaturize and become inactive
Why does a higher temp increase reaction rate of an enzyme (to a point)?
Caused by increased speed of substrates colliding with active sites
What is the optimal pH value for enzymes?
6-8
Any nonprotein molecule or ion that is required for the proper functioning of an enzyme
Cofactor
An organic molecule serving as a cofactor is called
coenzyme
Reduce the productivity of enzymes by BLOCKING substrates from entering active sites
Competitive inhibitors
Reduces the activity of an enzyme by binding to a location remote from the active site
Noncompetitive inhibitor
The binding of a regulatory molecule to a protein at one site that affects the function of a protein at a different site
Allosteric regulation of enzymes
A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway
Feedback inhibition
Products have less energy than reactant (-G)
Exergonic/spontaneous reactions
Products have higher energy than reactant (+G)
Endergonic/nonspontaneous reactions
Binding of a substrate molecule can stimulate the binding of activity at other active sites
cooperativity
Chemical reactions that involve a free energy change
Gibbs Free Energy
-G means ___________, while +G means ______________
Spontaneous, nonspontaneous
Changing pH disrupts what type of bonds (2)
Hydrogen and Ionic
