Biology Chapter 5

The capacity to do work

Measure of how much the energy of a system is dispersed

Energy cannot be created or destroyed

The energy of motion

Stored Energy

Energy tends to disperse spontaneously

Minimum amount of energy required to start a reaction

Describes a reaction that requires a net input of free energy to proceed

Describes a reaction that ends with a net release of free energy

A molecule that remains at the end of a reaction

A molecule that enters a reaction

Of an enzyme, pocket in which substrates bind and a reaction occurs

The acceleration of a reaction by a molecule that is unchanged by participating in the reaction

The concept that substrate binding to an active site of an enzyme improves the fit between the two molecules

A molecule that is specifically acted upon by an enzyme

Point during a reaction at which substrate bonds reach their breaking point and the reaction will run spontaneously

Describes a region of an enzyme that can bind a regulatory molecule and is not the active site

Array of enzymes and other molecules that accept and give up electrons in sequence, thus releasing the energy of the electrons in usable increments

Mechanism in which a change that results from some activity decreases or stops the activity

Series of enzyme-mediated reactions by which cells build, remodel, or break down an organic molecule

Oxidation-reduction reaction, in which one molecule accepts electrons (it becomes reduced) from another molecule (which becomes oxidized)

Substance that prevents oxidation of other molecules

The nucleotide adenosine triphosphate

Process by which cells regenerate ATP. ADP forms when ATP loses a phosphate group, then ATP forms again as ADP gains a phosphate group

An organic molecule that is a cofactor

A metal ion or a coenzyme that associates with an enzyme and is necessary for its function

Transfer of a phosphate group from one molecule to another

• Iron
• Magnesium
• Manganese
• Zinc
• Selenium
• Copper

• NADH, NAD+
• NADP, NADPH
• FAD, FADH, FADH₂
• CoA
• Heme
• Ascorbic Acid
• Biotin

Membrane protein that helps cells stick together in animal tissues

Model of a cell membrane as a two-dimensional fluid or mixed composition

Plasma membrane protein that binds to a particular substance outside of the cell

Plasma membrane protein that identifies a cell as belonging to self (one's own body)

Protein that passively or actively assists specific ions or molecules across a memrane

Number of molecules or ions per unit volume

Difference in concentration between adjoining regions of fluid

Spontaneous spreading of molecules or ions in a liquid or gas

Describes a fluid that has a high overall solute concentration relative to another fluid

Describes a fluid that has a low overall solute concentration relative to another field

Describes two fluids with identical solute concentrations

The diffusion of water across a selectively permeable membrane in response to a concentration gradient

Amount of turgor that prevents osmosis into cytoplasm or other hypertonic fluid

Pressure that a fluid exerts against a wall, membrane, or other structure that contains it

Energy-requiring mechanism in which a transport protein pumps a solute across a cell membrane against its concentration gradient

Active transport protein; pumps calcium ions across a cell membrane against their concentration gradient

Mechanism by which a concentration gradient drives the movement of a solute across a cell membrane through a transport protein, requires no energy input

Process by which a cell takes in a small amount of extracellular fluid by the ballooning inward of its plasma membrane

Process by which a cell expels a vesicle's contents to extracellular fluid

Cell eating; an endocytic pathway by which a cell engulfs particles such as microbes or cellular debris

Endocytosis of bulk materials