Topic 4 Flashcards
what are enzymes?
proteins
what are proteins?
polypeptide that is folded into a specific 3D shape
what is a peptide bond?
a polar covalent bond between amino acids
characteristics of hydrophobic R groups?
many non polar bonds
-inside away from water
characteristics of a hydrophilic R group?
side chains with oxygen, nitrogen or charged atoms
-on the outside of an amino acid
what happens when an acid loses a proton at ph7?
it becomes negatively charged
what happens when an acid gains a proton at ph7?
it becomes positively charged
what is a peptide?
polymer of amino acid
what is a polypeptide?
polymer of more than 10 amino acids
what is the primary structure of a polypeptide?
literal sequence of amino acids (straight line)
what is the secondary a structure of a polypeptide?
the primary structure folded into helices
-stabilized by hydrogen bonding by carboxyl groups and amide groups
what is the secondary b structure of a polypeptide?
primary sequence is folded into sheets
-stabilized by hydrogen bonds between carboxyl groups and amide groups
what is tertiary structure of a polypeptide?
the secondary structure is folded into the 3D shape of a protein
-due to multiple levels of interaction between the R-groups (HB, ionic interactions, Vanderwaals, covalent bonds)
what is quaternary structure of a polypeptide?
4 subunits each with tertiary structure
secondary structure of hexokinase?
helices, sheets, and turns made by the primary structure
tertiary structure of hexokinase?
overall shape of a protein which results from the organisation of secondary structural regions relative to another
what is activation energy?
the energy required to get a reaction going
how does activation energy work?
energy destabilizes the bonds in the reactants which allows the for the formation of the generation of products
what is a transition state?
the point where bonds in reactants are breaking and bonds of products are forming
-summit of Ea hill
what are ways to speed up a chemical reaction?
increase temperature
increase concentration of reactants
add a catalyst
what are examples of a catalyst?
enzyme- protein catalyst
robozyme- RNA catalyst
what do catalysts do?
decrease activation energy speeding up reaction time
what is an active site of an ezyme?
a region that interacts with one or more specific substrates
what happens when a substrate binds to an enzymes active site?
the enzyme changes shape forming an enzyme-substrate complex
what does the ES complex do?
forces the products into the transition state
how does an enzyme get back to how it was originally?
it released the products changing the enzymes back into its original shape
how do cells regulate enzyme kinetics?
by changing the concentration of inhibitors or the concentration of activators
what does the rate of an enzyme reaction depend on?
the concentration of enzyme and the concentration of substrate
what influences how fast a cell can convert substrate into products?
the rate of an enzyme reaction
what is denaturation?
loss of protien structure
characteristics of denaturation?
partial or complete
reversible or irreversible
caused by heat, pH and non-competitive inhibitors
what is inactivation?
loss of protein activity
characteristics of inactivation?
reversible or irreversible
due to denaturation
what is a reversible competitive inhibitor?
an inhibitor that is chemically like the substrate
-inhibitor noncovalently binds to an enzymes active site and competes with the substrate for binding to the active site
-molecule with the highest concentration outcompetes the other
what does competetive inhibition affect?
Km increases,
vm is the same
what is reversible non-competitive inhibition?
inhibitor is unlike the substrate
-inhibitor noncovalently binds to allosteric site
-high concentrations of substrate can’t outcompete inhibitor
what does a non-competitive inhibitor affect?
decreases Vmax,
Km stays the same
what are allosteric enzymes?
biochemical pathways that include regulatory enzymes that control the rate of the entire pathway
what are allosteric activators?
bind to the enzyme which will change shape to a more active form
what are allosteric inhibitors?
bind to the enzyme which will change shape to a less active form
what is feedback inhibition?
the final product of a pathway inhibits an enzymes early in the pathway
