UNit 3 Vocabulary Chapter 6

Matabolism

The totality of an organism’s chemical reaction. An emergent property of life that arises from orderly interactions between molecules.

Metabolic pathway

A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathways)

Catabolic pathways

Breaks down pathways (“uphill”)

breaks down complex to simple

• Ex: cellular respiration, build up larger molecules

Releases energy

Anabolic pathways

build up pathways (“downhill”)

build complex (complex from simple)

• Ex: Glucose —> CO2

Uses energy

Kinetic energy

The energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter

Potential energy

The energy that matter possesses as a result of its location or spatial arrangements (structure)

Chemical energy

Energy available in molecules for release in a chemical reaction; a form of potential energy.

Spontaneous process

A process that occurs without an overall input of energy; a process that is energetically favorable.

Free energy

Portion of a system’s energy that can perform work when temperature and pressure are uniform throughout the system.

More negative = more stable

delta G = G final - G initial

Exergonic reaction

Net release of free energy

delta G is negative

Endergonic reaction

Reaction that require energy to be absorbed

delta G is positive

Energy coupling

Occurs when the energy produced by 1 reaction or system is used to drive another (2nd) reaction or system.

Phophorylated intermediate

A molecule (often a reactant) with a phosphate group covalently bound to it, a making it more reactive (less stable) than the unphosphorylated molecule.

enzyme

a macromolecule (protein) that act as a catalyst

Catalyst

chemical agent that speeds up a reaction without being consumed by the reaction

Activation energy

Initial Investment of energy for starting a reaction

The energy required to contort the reactant molecules so the bonds can break

Amount of energy needed to push the reactants to the top of energy barrier (uphill) so that downhill can begin

Substrate

the reactant an enzyme acts on

the surface where an organism lives

• Ex: glucose, sucrose, and starch

Enzyme-substrate complex

A temporary complex formed when a enzyme binds to its substrate molecule(s)

Active site

The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs.

Induced fit

Caused by entry of the substrate, the change in shape of the active site of an enzyme so that it binds more snugly to the substrate.

Competitive inhibitors

Mimics the substrate, competes for active site (weak interactions, can be reversible)

non-competitives inhibitors

Binds to enzyme away from the active site, altering the shape of the enzyme so that even thought substrate binds active site, function is less effective.

Allosteric regulation

Any case in which a protein’s function at one site is affected by the binding of a regulatory molecule to separate site.

cooperativity

A kind of allosteric regulation whereby a shape change in one subunit of a protein caused by substrate binding is transmitted to all the other subunits, facilitating binding of additional substrate molecules to those subunits.

Feedback inhibition

A metabolic pathway is switched off by the inhibitory binging of its end product to an enzyme that adds early in the pathways.

Purpose: helps the cell maintain homeostasis or stable conditions.