2-3 Vocab

Question 1

Endocytosis

Answer 1

Cellular uptake of biological molecules and particulate matter via formation of vesicles from the plasma membrane

Question 2

Gated channels

Answer 2

A transmembrane protein channel that opens or closes in response to a particular stimulus

Question 3

Phosphorylation cascade

Answer 3

A series of chemical reactions during cell signaling mediated by enzymes (kinases), in which each kinase in turn phosphylates and activates another, ultimately leading to phosphorylation of many proteins

Question 4

Isotonic

Answer 4

Referring to a solution that, when surrounding a cell, causes no net movement of water into or out of the cell

Question 5

Electrochemical gradient

Answer 5

The diffusion gradient of an ion, which is affected by both the concentration difference of an ion across a membrane (a chemical force) and the ion’s tendency to move relative to the membrane potential (an electrical force)

Question 6

Glycoproteins

Answer 6

A protein with one or more covalent of attached carbohydrates

Question 7

Tonicity

Answer 7

The ability of a solution surrounding a cell to cause that cell to gain or lose water

Question 8

Hypertonic

Answer 8

Referring to a solution that, when surrounding a cell, will cause the cell to lose water

Question 9

Turgid

Answer 9

Swollen or distended, as in plant cells. (A walled cell becomes turgid if it has a lower water potential than its surroundings, resulting in entry of water)

Question 10

Fluid mosaic model

Answer 10

The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids

Question 11

Passive transport

Answer 11

The diffusion of a substance across a biological membrane with no expenditure of energy

Question 12

Ion channels

Answer 12

A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient

Question 13

Signal transduction pathway

Answer 13

A series of steps linking a mechanical, chemical, or electrical stimulus to a specific cellular response

Question 14

Diffusion

Answer 14

The random thermal motion of particles of liquids, gases, or solids. In the presence of a concentration or electrochemical gradient, diffusion results in the net movement of a substance from a region where it is more concentrated to a region where it is less concentrated

Question 15

Concentration gradient

Answer 15

A region along which the density of a chemical substance increases or decreases

Question 16

Selective permeability

Answer 16

A property of biological membranes that allows them to regulate the passage of substances across them

Question 17

Cotransport

Answer 17

The coupling of the “downhill” diffusion of one substance to the “uphill” transport of another against its own concentration gradient

Question 18

Facilitated diffusion

Answer 18

The passage of molecules or ions down their electrochemical gradient across a biological membrane with the assistance of specific transmembrane transport proteins, requiring no energy expenditure