Bio 101 Ch 5

Front 1

energy

Back 1

capacity to do work

Front 2

first law of thermodynamics

Back 2

any isolated system has a finite amount of energy that cannot be added or lost

Front 3

second law of thermodynamics

Back 3

entropy, or disorder of the universe always increases

Front 4

endergonic

Back 4

energy in

Front 5

exergonic

Back 5

energy release

Front 6

ATP

Back 6

adenosine triphosphate
gives up a phosphate group to other molecules and primes them to react

Front 7

phosphorylations

Back 7

phosphate group transfers

Front 8

ADP

Back 8

adenosine diphosphate
forms when ATP gives up phosphate group, can reform to ATP when it binds to inorganic phosphate

Front 9

ATP/ADP Cycle

Back 9

Cycle which drives most metabolic reactions

Front 10

reactants

Back 10

starting substances in a metabolic reaction

Front 11

intermediates

Back 11

substances found during a reaction sequence

Front 12

products

Back 12

substances left at the end of a reactions sequence

Front 13

enzymes

Back 13

catalysts that speed specific reactions enormously

Front 14

energy carriers

Back 14

activate enzymes and other molecules by making phosphate group transfers

Front 15

transport proteins

Back 15

helps solutes across membranes

Front 16

chemical equilibrium

Back 16

reaction rate is about the same in both directions

Front 17

oxidation-reduction reactions

Back 17

"redox reactions" in which cells release energy efficiently by electron transfers

Front 18

"redox" reactions

Back 18

one molecule gives up electrons and another gains them

Front 19

electron transfer chains

Back 19

membrane-bound arrays of enzymes and other molecules that accept and give up electrons in sequence

Front 20

metabolic pathways

Back 20

enzyme-mediated sequences of reactions in cells

Front 21

biosynthetic pathways

Back 21

sequences that require energy inputs

Front 22

degrative pathways

Back 22

sequences that break down molecules into smaller, lower energy products

Front 23

activation energy

Back 23

the minimum amount of internal energy that molecules must have before a reaction gets going

Front 24

substrates

Back 24

reactants taht bind to a specific enzyme

Front 25

active sites

Back 25

pockets or crevices where substrates bind and where specific reactions are catalyzed

Front 26

functional group transfers

Back 26

one molecule gives up a functional group to another

Front 27

electron transfers

Back 27

one or more electrons stripped from one molecule are donated to another

Front 28

rearrangements

Back 28

juggling of internal bonds converts one molecule to another

Front 29

condensation

Back 29

two molecules are covalently bound together as a larger molecule

Front 30

cleavage

Back 30

larger molecule splits into smaller ones

Front 31

transition state

Back 31

time in a reaction at which a bonds are at a breaking point and the reaction can run easily to product

Front 32

induced-fit model

Back 32

substrateis not quite complementary to an active site, so enzyme bends and optimizes fit, and so pulls the substrate to the transition state

Front 33

coenzymes

Back 33

a cofactor, a class of organic compounds that may or may not have a vitamin component

Front 34

antioxidants

Back 34

help neutralize free radical

Front 35

cofactor

Back 35

help out at the active site of enzymes or taxi electrons,
specific metal ions or coenzymes

Front 36

free radicals

Back 36

atoms with unpaired electrons, reactive, unbound fragments left over from reactions

Front 37

allosteric site

Back 37

alternate site on enzyme where a molecule binds to the enzyme to act as an inhibitor or activator

Front 38

feedback inhibition

Back 38

a change that results from a specific activity shuts down the activity

Front 39

selective permeability

Back 39

molecular structure that allows some substances but not others to cross it in certain ways, at certain tiems

Front 40

concentration gradient

Back 40

difference in the number per unit volume of ions or molecules of a substance between adjoining regions

Front 41

diffusion

Back 41

net movement of like molecules or ions down a concentration gradient

Front 42

electric gradient

Back 42

difference in electric charge between adjoining regions

Front 43

pressure gradient

Back 43

difference in exerted force per unit of area in two adjoining regions

Front 44

passive transports

Back 44

"facilitated diffusion", simply allowing a substance to follow its concentration gradient across a membrane

Front 45

active transport

Back 45

energy-driven protein motors help move a specific solute across membrane against the concentration gradient

Front 46

exocytosis

Back 46

fusion of the plasma membrane and a membrane-bound vesicle that formed inside the cytoplasm

Front 47

endocytosis

Back 47

inward sinking of a patch of plasma membrane, which seals back on itself to form a vesicle inside the cytoplasm

Front 48

calcium pump

Back 48

active transporter that helps keep the concentration of calcium in a cell at least a thousand times lower than the outside

Front 49

sodium-potassium pump

Back 49

active transporter that mediates teh movement of sodium ions from the cytoplasm into the open channel to bind to functional groups, so that the ATP can prompt the pump to change shape and release the sodium ions outside the cell

Front 50

bulk flow

Back 50

mass movement of one or more substances in response to pressure, gravity, or another external force

Front 51

osmosis

Back 51

diffusion of water across a selectively permeable membrane

Front 52

tonicity

Back 52

the relative solute concentrations of two fluids

Front 53

hypotonic solution

Back 53

when two fluids on opposing sides of a membrane differ in solute concentrations, the side with less solutes

Front 54

hypertonic solution

Back 54

when two fluids on opposing sides of a membrane differ in solute concentrations, the side with more solutes

Front 55

isotonic solutions

Back 55

no net osmotic movement

Front 56

hydrostatic pressure

Back 56

force that any volume of fluid exerts against a wall, a membrane, or some other structure enclosing it

Front 57

osmotic pressure

Back 57

amount of force preventing any further increase in volume

Front 58

receptor-mediated endocytosis

Back 58

receptors at the membrane bind to molecules of a hormone, vitamin, mineral, or another substance

Front 59

phagocytosis endocytosis

Back 59

common endocytic pathway in which phagocytes such as amoebas englulf the microbes, food particles, or cellular debris

Front 60

bulk-phase endocytosis

Back 60

not as selective, vesicle forms around a small volume of the extracellular fluid