HumBio3A-Notes3 Flashcards
Why ATP
versatile currenty of energy that all cells can use
Enzymes
marvelous cellular tools that extract energy from nutrients and deploy it for the work cells need to do
How do Enzymes work?
active sites, reaction mechanisms, vitamins and co-factors
What is catalysis?
When an enzyme is used to lower the activiation barrier for a specific reaction
Analogy for metabolic pathways
decision tree
metabolic pathways
chain of reactions that guide series of enzyem reactions
Are enzymes in a metabolic pathway often found in close proximity?
yes, this aids efficiency. It’s very common for them to cluster
3 ways that enzyems encourage reactions
enzyme binds two substrates, binding to substrate rearranges electrons to favor reactions, enzyme cleaves or strains the bound of the substrate, forcing toward a transition
How do enzymes maintain specificity?
The key is in the form or structure
What is a ligand?
anything that an enzyme bonds to
two meanings of ligand
something that binds to an enzyme (substrate), or something that binds to a signaling receptor
Can enzymes be recycled?
yes! Once the reaction is complete, the enzyme persists, unchanged
enzyme substrate complex changes to the ________
enzyme product complex
How does lysozme work?
it cleaves/cuts a polysaccharide at a specific covalent bond
Are enzymes static?
no, substrate binding causes conformational change (ex. Bacterial hexokinase)
Can a substrate alter an enzyme?
Yes! A substrate binding can change the form/structure of the enzyme and assist in reactions or exclusion
Is an enzyme the only element required for these reactions?
No, there are often cofactors that can assist or be required for the reaction. Vitamins and other environmental minerals can be required
What’s a competitive inhibitor?
a molecule that resembles a substrate, and subsequently excludes substrate from binding site.
What is malonate?
an inhibitor that prevents succinate from binding to succinate dehydrogenase, preventing conversion to fumarate during glucose metabolism
Why does methanol kill us?
Alcohol dehydrogenase , which would normally convert ethanol to Acetaldehyde, converts the methanol to formyldehyde
What is negative regulation?
when a resultant protein actually inhibits a predecessor enzyme and stops the metabolic pathway
Allosteric regulation
the enzyme has two binding sites, one for the substrate, and another for regulatory inhibition - TWO BINDING SITES!!
