Cell Biology Test One Vocab Chapter Two

Front 1

Activated monomer

Back 1

A monomer whose free energy has been increased by being linked to a carrier molecule

Front 2

Amphipathic molecules

Back 2

Molecule having spatially separated hydrophilic and hydrophobic regions

Front 3

Asymmetric carbon

Back 3

Carbon atom that has four different substituents. Two different stereoisomers are possible for each asymmetric carbon atom in an organic molecule.

Front 4

Bond energy

Back 4

Amount of energy required to break one mole of a particular chemical bond

Front 5

Calorie

Back 5

Unit of energy; amount of energy needed to raise the temperature of one gram of water by one degree Celsius

Front 6

Carrier molecule

Back 6

A molecule that joins to a monomer, thereby activating the monomer for a subsequent reaction

Front 7

Cellulose

Back 7

Structural polysaccharides present in plant cell walls, consisting of repeating glucose units linked by beta 1->4 bonds

Front 8

Chitin

Back 8

Structural polysaccharide found in insect exoskeletons and crustacean cells; consists of N-acetylglucosamine unites linked by beta 1->4 bonds.

Front 9

Condensation reaction

Back 9

Chemical reaction that results in the joining of two molecules by the removal of a water molecule.

Front 10

Covalent bond

Back 10

Strong chemical bond in which two atoms share two or more electrons

Front 11

Denaturation

Back 11

Loss of the natural three-dimentional structure of a macromolecule, usually resulting in a loss of its biological activity; caused by agents such as heat, extremes of pH, urea, salt, and other chemicals.

Front 12

Directionality

Back 12

Having two ends that are chemically different from each other; used to describe a polymer chain such as a protein, nucleic acid, or carbohydrate; also used to describe membrane transport systems that selectively transport solutes across a membrane in one direction

Front 13

Electronegativity

Back 13

Property of an atom that tends to draw electrons toward it.

Front 14

Functional groups

Back 14

Group of chemical elements covalently bonded to each other that confers characteristic chemical properties upon any molecule to which it is covalently linked

Front 15

Glycogen

Back 15

highly branched storage polysaccharide in animal cells; consists of glucose repeating subunits linked by alpha 1->4 bonds and alpha 1->6 bonds

Front 16

Hydrocarbon

Back 16

An organic molecule consisting only of carbon and hydrogen atoms; not generally compatible with living cells

Front 17

Hydrogen bond

Back 17

Weak attractive interaction between an electronegative atom and a hydrogen atom that is covalently linked to a second electronegative atom

Front 18

Hydrolysis

Back 18

Reaction in which a chemical bond is broken by the addition of a water molecule

Front 19

Hydrophilic

Back 19

Describing molecules or regions of molecules that readily associate with or dissolve in water because of a preponderance of polar groups. "Water-loving"

Front 20

Hydrophobic

Back 20

Describing molecules or regions of molecules that are poorly soluble in water because of preponderance of non-polar groups. "water-hating"

Front 21

Hydrophobic interaction

Back 21

Tendency of hydrophobic groups to be excluded from interactions with water molecules.

Front 22

Ionic bond

Back 22

attractive force between a positively charged chemical group and a negatively charged chemical group

Front 23

Macromolecule

Back 23

Polymer built from small repeating monomer units, with molecular wights ranging from a few thousand to hundreds of millions

Front 24

Molecular chaperones

Back 24

A protein that facilitates the folding of other proteins but is not a component of the final folded structure

Front 25

Monomer

Back 25

Small organic molecule that serves as a subunit in the assembly of a macromolecule

Front 26

Noncovalent bonds and interactions

Back 26

Binding forces that do not involve the sharing of electrons; examples include ionic bonds, hydrogen bonds, van der Waals interactions, and hydrophobic interactions

Front 27

Phospholipids

Back 27

Lipid possessing a covalently attached phosphate group and therefore exhibiting both hydrophilic and hydrophobic properties; main component of the lipid bi-layers that forms the structural backbone of all cell membranes

Front 28

Polypeptide

Back 28

Linear chain of amino acids linked by peptide bonds

Front 29

Renaturation

Back 29

Return of a protein from a denatured state to the native conformation determined by its amino acid sequence, usually accompanied by restoration of physiological function

Front 30

Specific heat

Back 30

amount of heat needed to raise the temperature of one gram of substance on degree Celsius

Front 31

Starch

Back 31

Storage polysaccharide in plants consisting of repeating glucose subunits. The two main forms of starch are the unbranched pollysaccharide, amylose, and the branched polysaccharide, amylopectin.

Front 32

Stereoisomers

Back 32

Two molecules that have the same structural formula but are not superimposable; stereoisomers are mirror images of each other.

Front 33

Van der Waals interaction

Back 33

Weak attractive interaction between two atoms caused by transient asymmetries in the distribution of charge in each atom

Front 34

Dalton, or atomic mass unit

Back 34

the standard unit that is used for indicating mass on an atomic or molecular scale (atomic mass).

Front 35

Electrostatic interaction

Back 35

Coulomb's law: The fundamental law of electrostatics stating that the force between two charged particles is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.

Front 36

Membrane lipid bilayer

Back 36

a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around cells. The lipid bilayer is the barrier that keeps ions, proteins and other molecules where they are needed and prevents them from diffusing into areas where they should not be. Natural bilayers are usually composed of phospholipids, which have a hydrophilic head and two hydrophobic tails each. When phospholipids are exposed to water, they arrange themselves into a two-layered sheet (a bilayer) with all of their tails pointing toward the center of the sheet.

Front 37

Membrane proteins

Back 37

constitute one of the three main protein classes, with the other classes being the fibrous and globular proteins. Membrane proteins are attached to, or associated with the membrane of a cell or an organelle.

Front 38

Polymer

Back 38

a large molecule composed of many repeated subunits, known as monomers. Because of their broad range of properties,[4] both synthetic and natural polymers play an essential and ubiquitous role in everyday life.[5] Polymers range from familiar synthetic plastics such as polystyrene (of styrofoam) to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function.

Front 39

Spheres of hydration

Back 39

When solutes are dissolved in water, many water molecules cluster around each solute molecule(attracted by polarity) This keeps the solute dispersed in the fluid. The water molecules in these "spheres" are tied up and not free to cross a water permeable membrane.