activation energy
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active site
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active transport
-must expand energy to move a solute against its concentration gradient
-ATP supplies the energy
*goes against concentration gradient
aquporin
protein channel
-rapid diffusion of water into and out of certain cells
ATP
powers nearly all forms of cellular work
-consists of adenosine and a tail of 3 triphosphate groups
-hydrolysis of ATP is exergonic
-renewable
cellular respiration
chemical energy stored in organic molecules
-used to produce ATP
chemical energy
-potential energy available for release in a chemical reaction
-the most important type of energy for living organisms to power the work of the cell
coenzyme
cofctor that is a organic molecule (folic acid)
cofactor
non protein helpers
-bind to the active site and function in catalysis
-some are inorganic (ions of zinc, iron, and copper)
competitive inhibitor
-block substrates from entering the active site
-reduce an enzyme's productivity
concentration gradient
process of particles, which are sometimes called solutes, moving through a solution or gas from an area with a higher number of particles to an area with a lower number of particles
diffusion
tendency of particles to spread out evenly in an available space
-particles move from an area of more concentrated particles to an area where they are less concentrated
endergonic reaction
require an input of energy and store energy
-yields products rich in potential energy
endocytosis
transport process through which a cell takes in large molecules
energy
a capacity to cause change or perform work
energy coupling
uses the energy released from exergonic reactions to drive endergonic reactions
-uses energy stored in ATP molecules
entropy
measure of disorder or randomness
enzyme
speed us cell's chemical reactions by lowering energy barriers
-molecules that function as biological catalysts
-increase the rate of a reaction without being consumed by the reaction
-most are proteins
-lowers activation energy needed for a reaction to b
exergonic reaction
release energy
-release the energy in covalent bonds of the reactants
-burning wood releases the energy in glucose as heat and light
-begins with reactants whose covalent bonds contain more potential energy than those in the products
exocytosis
used to export bulky mlecules such as proteins or polysaccarides
facilitated diffusion
help polar/charged substances to move across membranes
-does not require energy
-relies on concentration gradient
feedback inhibition
in a reaction, when the product acts as an inhibitor of one of the enzymes in the pathway that produced it
-when the product is used up by the cell, the enzymes is no longer inhibited and the pathway functions again
first law of thermodynamics (law of energy conservation)
energy in the universe is constant
-energy CAN be transferred and transformed, but NOT created or destroyed
fluid mosaic model
a patchwork of diverse protein molecules embedded in a phospholipid bilayer
-proteins embedded perform specific functions
-plasma membrane exhibits selective permeability
heat
thermal energy in transfer from one object to another
hypertonic
-the solute concentration is higher outside the cell
-water molecules move out of the cell
-cell shrinks
hypotonc
-solute concentration is lower outside the cell
-water molecules move into the cell
-cell will expand and an burst
isotonic
-concentration of solute is the same on both sides of a membrane
-cell volume will not change
kinetic energy
energy of motion
-transfer motion to other matter
matabolic pathway
series of chemical reactions that either build a complex molecule or break down a complex molecule into simpler compounds
-ex= slow burn of cellular respiration
metabolism
total amount of an organisms chemical reactions
noncompetitive inhibitor
-bind to the enzyme somewhere other than the active
-change the shape of the active site
-prevent the substrate from binding
osmoregulation
the control of water balance
-needed for animal cells to survive in hypotinic or hypertonic environment
osmosis
diffusion of water across a selectively permeable membrane
passive transport
diffusion across a cell membrane does not require energy
phagocytosis
cellular eating"
engulfment of a particle by the cell wrapping cell membrane around it, forming a vacuole
phosphorlyation
hydrolysis of ATP releases energy by transferring its third phosphate from ATP to some other molecule
potential energy
energy that matter possesses as a result of its location or structure
-molecules possess potential energy because of the arrangements of electrons in the bonds between their atoms
receptor-mediated endocytosis
uses membrane receptors for specific solutes
-region of the membrane with receptors pinches inward to form a vesicle
-used to take in cholesterol from blood
second law of thermodynamics
energy conversions increase the entropy (disorder) of the universe
substrate
specific reactant that an enzyme acts on
-in the active site
thermal energy
type of kinetic energy associated with the random movement of atoms or molecules
thermodynamics
study of energy transformations that occur in a collection of matter
system: matter under the study
surroundings: everything outside the system, the rest of the universe
tonicity
describes the ability of a surrounding solution to cause a cell to gain or lose water
-mainly depends on its concentration of solutes inside the cell