Chapter 6

Question 1

Active Transport

Answer 1

moving substances against the concentration/electrical gradient. Requires cellular energy, driven by ATP hydrolysis, requires a membrane protein, and is specific

Question 2

Antiporter

Answer 2

moving two substances in opposite directions

Question 3

Aquaporin

Answer 3

special channels that allow water to cross membranes

Question 4

Carrier proteins

Answer 4

membrane proteins that bind substances and speed their diffusion through the bilayer

Question 5

cell adhesion

Answer 5

strengthening of the connection between two cells

Question 6

cell junctions

Answer 6

specialized structures that hold cells together

Question 7

cell recognition

Answer 7

cells recognize each other and bind to another cell of a certain type

Question 8

concentration gradient

Answer 8

difference in concentration between two sides of a cell membrane

Question 9

channel proteins

Answer 9

integral membrane proteins that form a tunnel

Question 10

desmosome

Answer 10

“spot welds” (materials move around in extracellular matrix)

Question 11

endocytosis

Answer 11

brings molecules together in eukaryotic cells (cell eating)

Question 12

diffusion

Answer 12

random movement to equalibrium

Question 13

fluid mosaic model

Answer 13

describes general structure of biological membranes

Question 13

exocytosis

Answer 13

materials in vesicles are expelled from the cell

Question 14

facilitated diffusion

Answer 14

passive movement of polar molecules through a membrane, no energy required, driven by concentration gradient, requires a membrane protein, and is specific

Question 15

gated channel

Answer 15

can be closed or
open to ion passage

Question 15

gap junctions

Answer 15

allow communication

Question 16

glycolipid

Answer 16

carb+lipid

Question 17

Hypertonic

Answer 17

high solute concentration

Question 18

homotypic

Answer 18

same molecule sticks out from
both cells and bind to each other

Question 18

heterotypic

Answer 18

cells have different proteins that
bind together

Question 19

glycoprotein

Answer 19

carb+protein

Question 20

Hypotonic

Answer 20

low solute concentration

Question 21

integrin

Answer 21

proteins that help cells attach to each other and to the ECM

Question 21

ion channel

Answer 21

channel proteins with hydrophilic pores

Question 21

integral membrane proteins

Answer 21

have hydrophobic and hydrophilic regions; some extend across bilayer, others partially embedded

Question 22

isotonic

Answer 22

equal solute concentration

Question 23

peripheral membrane proteins

Answer 23

lack hydrophobic regions so do not penetrate bilayer

Question 24

ligand

Answer 24

a molecule that can bind to a receptor

Question 25

passive transport

Answer 25

no energy required

Question 26

phagocytosis

Answer 26

molecules or entire cells are engulfed

Question 27

pinocytosis

Answer 27

vesicle forms to bring small dissolved substances or fluids into a cell

Question 28

primary active transport

Answer 28

requires direct hydrolysis of ATP

Question 29

receptor protein

Answer 29

integral membrane proteins located at specific sites on cell membrane; sites coated with other proteins

Question 30

receptor mediated endocytosis

Answer 30

very specific; macromolecules bind to receptor proteins

Question 31

secondary active transport

Answer 31

energy comes from ion concentration gradient established by primary active transport

Question 32

selective permeability

Answer 32

only some things enter and exit the cell membrane

Question 33

simple diffusion

Answer 33

small molecules pass through lipid bilayer, no energy required, driven by concentration gradient, no membrane protein required, not specific

Question 34

sodium potassium pump

Answer 34

found in animal cells; an integral membrane glycoprotein (an antiporter)

Question 35

symporter

Answer 35

moving two substances in the same direction

Question 36

tight junction

Answer 36

prevent substances from moving through spaces between cells; help ensure directional movement of materials

Question 37

transmembrane domains

Answer 37

on inner or outer side of bilayer, have specific functions

Question 38

transmembrane proteins

Answer 38

extend all the way through phospholipid bilayer, contain one or more transmembrane domains

Question 39

turgor pressure

Answer 39

plant cells with rigid cell walls build up internal pressure that keeps more water from entering

Question 40

uniporter

Answer 40

moves one substance in one direction