Biology Chapter 7

Front 1

Peripheral Proteins

Back 1

bound to surface of membrane

Front 2

Integral Proteins

Back 2

penetrate the hydrophobic core

Front 3

selective permeability

Back 3

some substances to cross more easily than others

Front 4

Fluid mosaic model

Back 4

membrane is a fluid structure with a “mosaic” of various proteins embedded in it

Front 5

Six major functions of membrane proteins

Back 5

1.Transport

2.Enzymatic activity

3.Signal transduction

4.Cell-cell recognition

5.Intercellular joining

6.Attachment to the cytoskeleton and extracellularmatrix (ECM)

Front 6

glycolipids

Back 6

Membrane carbohydrates may be covalentlybonded to lipids

Front 7

glycoproteins

Back 7

Membrane carbohydrates may be bonded to proteins

Front 8

Transport proteins

Back 8

allow passage of hydrophilicsubstances across the membrane

Front 9

aquaporins

Back 9

facilitate thepassage of water

Front 10

Diffusion

Back 10

tendency for molecules to spread out evenly into the available space.

Front 11

concentration gradient

Back 11

the region along which the density of achemical substance increases or decreases

Front 12

passive transport

Back 12

no energy is expended by the cell to make it happen

Front 13

Osmosis

Back 13

diffusion of water across a selectively permeable membrane

Front 14

Tonicity

Back 14

ability of a surrounding solution to causea cell to gain or lose water

Front 15

Isotonic Solution

Back 15

solute concentration is the sameas that inside the cell; no net water movement across the plasma membrane

Front 16

Hypertonic Solution

Back 16

solute concentration is greater than that inside the cell; cell loses water

Front 17

Hypotonic Solution

Back 17

solute concentration is less than that inside the cell; cell gains water

Front 18

Osmoregulation

Back 18

the control of solute concentrations and water balance, it is a necessary adaptation for life in such environments

Front 19

Turgid

Back 19

firm

Front 20

Flaccid

Back 20

limp

Front 21

Plasmolysis

Back 21

plant cells lose water;eventually, the membrane pulls away from the cell wall causing the plant to wilt.

Front 22

Facilitated diffusion

Back 22

transport proteins speed thepassive movement of molecules across membrane; include channel proteins and carrier proteins

Front 23

Ion channels

Back 23

facilitate the diffusion of ions

Front 24

Gated channels

Back 24

open or close in response to a stimulus

Front 25

Active transport

Back 25

moves substances against their concentration gradients

Front 26

Membrane potential

Back 26

voltage difference across a membrane

Front 27

electrochemical gradient

Back 27

drive the diffusion of ions across a membrane

Front 28

Electrogenic pump

Back 28

transport protein that generates voltage across a membrane

Front 29

proton pump

Back 29

The main electrogenic pump of plants, fungi, and bacteria

Front 30

Cotransport

Back 30

active transport of a solute indirectly drives transport of other substances

Front 31

Exocytosis

Back 31

transport vesicles migrate to the membrane, fuse with it, and release their contents outside the cell

Front 32

Endocytosis

Back 32

cell takes in macromolecules by forming vesicles from the plasma membrane

Front 33

three types of endocytosis

Back 33

1.Phagocytosis (“cellular eating”) cell engulfs particle in a vacuole.

2.Pinocytosis (“cellular drinking”) molecules taken up when extracellular fluid is “gulped” into tiny vesicles.

3.Receptor-mediated endocytosis: binding of ligands to receptors triggers vesicle formation.