Membrane Transport

Question 1

Boundary that separates the living cell from its surroundings. Exhibits selective permeability. Allows some substance to cross the membrane more easily than other substance

Answer 1

Plasma membrane

Question 2

Most abundant lipid in the plasma membrane

Answer 2

Phospholipids

Question 3

Contain both hydrophilic and hydrophobic regions

Answer 3

Amphipathic molecules

Question 4

can exist as a stable boundary between 2 aqueous compartments

Answer 4

phospholipid bilayer

Question 5

A membrane that is a fluid structure with a “mosaic” of various proteins embedded in it. Proteins are not randomly distributed in the membrane

Answer 5

Fluid Mosaic Model

Question 6

direction where lipids, and some proteins drift

Answer 6

laterally

Question 7

determine most of the membrane’s specific functions

Answer 7

Membrane protein

Question 8

Proteins Bound to the surface of the membrane

Answer 8

Peripheral protein

Question 9

Proteins that Penetrate the hydrophobic core

Answer 9

Integral proteins

Question 10

Integral proteins that span the membrane

Answer 10

Transmembrane protein

Question 11

6 major function of membrane proteins

Answer 11

transport, enzymatic activity, signal transduction, cell to cell recognition, intercellular joining, attachment

Question 12

Role of Membrane Carbohydrates in Cell-Cell Recognition

Answer 12

Cells recognize each other by binding to molecules, often containing carbohydrates, on the extracellular surface of the plasma membrane

Membrane carbohydrates may be
covalently bonded to lipids (glycolipids) or more commonly to proteins (glycoproteins)

Carbohydrates on the external side of the plasma membrane vary among species, individuals, and even cell types in an individual

Question 13

Can dissolve in the lipid bilayer and pass through the membrane rapidly

Answer 13

Hydrophobic

Question 14

Includes ions and polar molecules that do not pass the membrane easily

Answer 14

Hydrophilic

Question 15

Allows the passage of hydrophilic substance across the membrane

Answer 15

Transport Proteins

Question 16

With hydrophilic channel that certain molecules can use as a tunnel (transport protein)

Answer 16

Channel proteins

Question 17

Facilitate the passage of water (under channel protein)

Answer 17

Aquaporins

Question 18

Bind to molecules and change shape to shuttle them across the membrane, uses energy (transport protein)

Answer 18

Carrier proteins

Question 19

Movement of molecules from an area of higher concentration to an area of lower concentration without any energy investment
The tendency for molecules to spread out evenly into the available space

Answer 19

Diffusion

Question 20

Substances diffuse down their concentration gradient
No work must be done to move the substances down the gradient (type of transport)

Answer 20

Passive Transport

Question 21

Diffusion of water across the selectively permeable membrane from the region of lower solute concentration to the region of higher solute concentration until the concentration is equal on both sides

Answer 21

Osmosis

Question 22

Ability of a surrounding solution to cause a cell to gain or lose water

Answer 22

Tonicity

Question 23

Solute concentration is the same as inside the cell. No net movement of water across the membrane

Answer 23

Isotonic solution

Question 24

Solute concentration is greater outside the cell
Cell loses water, Cell becomes shrivelled

Answer 24

Hypertonic solution

Question 25

Solute concentration is less than the inside of cell. Cell gains water, Cell may swell or burst

Answer 25

Hypotonic solution

Question 26

Control of solute concentrations and water balance Needed for organisms that has problems with the hypertonic or hypotonic environments

Answer 26

Osmoregulation

Question 27

Transport proteins speed up the passive movement of molecules across the plasma membrane

Answer 27

Facilitated Diffusion

Question 28

Undergo subtle change in shape that translocates the solute-binding site across the membrane (facilitated diffusion)

Answer 28

Carrier proteins

Question 29

Provide corridors to allow specific molecules to cross the membrane (facilitated diffusion)

Answer 29

Channel proteins

Question 30

Facilitate diffusion of water

Answer 30

Aquaporin

Question 31

Facilitate diffusion of ions. Some are known as gated channels. They open and close in response to a stimulus (facilitated diffusion)

Answer 31

lon channel

Question 32

Moves substances against their concentration gradient Requires energy, usually in the form of ATP Performed by specific proteins embedded in the plasma membrane Allows cells to maintain concentration gradients that differ than their surroundings Sodium-potassium pump is one type of the active transport

Answer 32

Active Transport

Question 33

Voltage difference across a membrane Created by differences in the distribution of positive and negative ions across a membrane

Answer 33

Membrane Potential

Question 34

2 combined forces, Drive the diffusion of ions across a membrane

Answer 34

Electrochemical Gradient

Question 35

lon's concentration gradient (force)

Answer 35

Chemical force

Question 36

Effect of membrane potential on the ion's movement (force?

Answer 36

Electrical force

Question 37

A transport protein that generates voltage across the membrane, Help store energy that can be used for cellular work

Answer 37

Electrogenic Pump

Question 38

Major electrogenic pump for animal cells

Answer 38

Sodium-potassium pump

Question 39

Major electrogenic pump for plants, fungi, and bacteria

Answer 39

Proton pump

Question 40

Coupled transport by a membrane protein Occurs when active transport of a solute indirectly drives transport of

Answer 40

Cotransport

Question 41

same direction of passage in cotransport

Answer 41

Symport

Question 42

opposite direction of passage in cotransport

Answer 42

antiport

Question 43

Movement of proteins or macromolecules into and out of the cell, Requires energy

Answer 43

Bulk Transport

Question 44

2 types of Bulk Transport

Answer 44

* Exocytosis * Endocytosis

Question 45

Transport vesicles migrate to the membrane, fuse it, and release their contents outside the cell * Many secretory cells use exocytosis to export their products

Answer 45

Exocytosis

Question 46

Cells take in macromolecules by forming vesicles from plasma membrane

Answer 46

Endocytosis

Question 47

3 types of Endocytosis

Answer 47

Phagocytosis, Pinocytosis, Receptor-mediated endocytosis

Question 48

cellular eating, Cell engulfs a particle in a vacuole. The vacuole fuses with a lysosome to digest the particle

Answer 48

Phagocytosis

Question 49

cellular drinking, Molecules dissolved in droplets are taken up when extracellular fluid is "gulped" into tiny vesicles

Answer 49

Pinocytosis

Question 50

Binding of ligands to receptors triggers vesicle formation

Answer 50

Receptor-mediated endocytosis

Question 51

Any molecule that binds specifically to a receptor site of another molecule

Answer 51

Ligand

Question 52

2 HIV receptors

Answer 52

CD4 and CCR5