How do Salmon navigate both worlds? Part 2 Flashcards
What is energy?
The capacity to do work
(in biological systems: the capacity for change)
What are enzymes?
A catalytic protein that speed up a reaction without being consumed by it.
They work to help cells acquire and use energy by lowering activation energy
What is activation energy?
The initial energy needed to start a chemical reaction
What is the link between enzymes, activation energy and free energy?
It does not affect the change in free energy, but it hastens reactions that would occur eventually
How do enzymes lower activation energy?
They lower it by:
Orienting substrates correctly (putting substrates in correct orientation so they react with each other)
Straining substrate bonds (More strain=easier to break)
Providing. a favorable chemical microenvironment (Changing pH, making sure reactants and irons are close)
Covalently bonding to the substrate
What is the enzyme hallmark?
An enzyme always returns to its original state by the completion of the reaction and can therefore be used again.
What do enzymes work with?
Cofactors
Coenzymes
Prosthetic Groups
What are Cofactors?
Inorganic ions that reversibly interact with enzymes; can dissociate and are usually metals.
Zinc, Magnesium, Iron
What are Coenzymes?
Organic molecules that interact, where some are reversible and some are not.
NADH or FADH
What are Prosthetic Groups?
Non amino acid atoms or molecules permanently attached to proteins; do not associate
What conditions affect enzyme activity?
Temperature
pH
Modifications of primary structure
Interactions with other molecules
(Enzymes are super picky)
What are regulatory molecules?
They regulate cells enzymatic activity by:
- Changing enzyme structure
- Ability to bind to substrates and reactions
- May activate or inactivate the enzymes
What is the specific type of activity curve of an enzyme called?
Saturation Kinetics
What is saturation point?
The point where every enzyme is bound and working so you can no longer speed up the reaction
What is a competitive inhibitor?
A regulatory molecule that binds to the active site of an enzyme, competing with the substrate.
What is an allosteric regulation?
Regulatory molecule binds to another part of an enzyme called allosteric site, causing the enzyme to change shape making it less effective.
It may inhibit or stimulate and enzyme’s activity.
What are covalent modifications?
Changes in enzyme primary structure that can be reversible or irreversible being the clearage of peptide bonds
What is the most common reversible modification?
Phosphorylation: the addition of covalent bonds with phosphate
What happens during phosphorylation?
Changes shape of enzyme (activates or deactivates it)
Reversible modification to protein structure
What is the reversible modification of phosphorylation?
Dephosphorylation
What are Metabolic Pathways?
A series of ordered reactions that build up or break down a molecule
What role do enzymes play in Metabolic Pathways?
Each step is catalyzed by a different enzyme
In metabolic pathways we can regulate enzymes involved; It is easier to turn off a single step than every step
What is Feedback Inhibition?
Occurs when enzyme in pathway is inhibited and is by final product of pathway
What happens as concentration of product becomes abundant?
It “feeds back” to stop reaction
Amount of initial substrate is not depleted
Stored or used for other reactions
