Enzymes - AP Bio Unit 3

Metabolism

Sum of all chemical reactions in a cell/organism

Metabolic Pathway

A series of steps in which a molecule is altered to create a product; each step is catalyzed by an enzyme

Catabolic Pathway

A series of chemical reactions that break down complex molecules into simple ones

Cellular Respiration

Breakdown of glucose in the presence of oxygen into ATP

Anabolic Pathway

consumes energy to create complex molecules from simpler ones; helps organize universe

Bioenergetics

study of how organisms manage their energy resources

Enzyme

A catalytic protein that speeds up metabolic reactions by lowering activation energy

Catalyst

chemical agent that speeds up a reaction without being consumed

Substrate

the reactant that is acted on by the enzyme. enzyme binds to this.

Active Site

the region where the enzyme and the substrate binds. Substrate. must have complimentary shape to this in order to fit.

Induced Fit

brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction

Activation Energy

Initial energy needed to start a chemical reaction (ex: thermal energy from environment)

Endergonic

chemical reactions that require a net input of energy (for forming stuff)

Exergonic

chemical reactions that require a net loss of energy (for breaking stuff apart)

Denaturation

loss a protein’s shape, native structure or conformation; Makes them biologically inactive; can be reversed sometimes (enzymes cannot catalyze when this occurs)

pH

a factor that can alter protein structure due to high concentration of protons —> alters hydrogen bonds in protein = loss of secondary & tertiary structure

temperature

a factor that can alter protein structure by increasing amount of kinetic = more collisions, but reaction rate decreases after hitting max

concentration

a factor that alter reaction rate if there are too many enzymes, not enough substrate (vice versa)

inhibition

Cells stop producing molecules when it’s demand is met or homeostasis is restored

Negative feedback

allows cell to avoid wasting energy/resources; the product of the pathway inhibits the process responsible for production

Competitive inhibitors

binds to the active site of an enzyme and competes with the substrate

Noncompetitive inhibitors

binds to another part of the enzyme causing the enzyme to change shape making the active site less effective

Allosteric regulation

either inhibits or stimulates an enzyme’s activity; Occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function on another site

Thermodynamics

the study of energy transformations

First law of thermodynamics

energy of the universe is constant; Energy can be transferred or transformed but not created or destroyed

Second law of thermodynamics

every energy transfer or transformation increases the entropy (disorder) of the universe

Cellular Thermodynamics

Living cells convert organized forms of energy into heat

Spontaneous processes

processes that occur without energy input; happen very quickly or slowly; increases the entropy of the universe

Catabolic pathway

in a cell releases free energy in a series of reactions; are how cells perform work

Energy coupling

how cells manage energy resources in order to do work; using an exergonic process to drive/power a endergonic one (usually mediated by ATP)

ATP

A renewable source of energy that is composed of a ribose sugar, adenine (a nitrogenous base) and three phosphate groups. Energy is released when its tail is broken