Ap Bio Midterm - Chapter 8

Front 1

Has both a hydrophilic and a hyrdophobic region

Back 1

Amphipathic Molecule

Front 2

Membrane is a fluid structure with various proteins embedded or attatched to the phospholipid bilayers

Back 2

Fluid mosaic model

Front 3

Stabilizes the cell membrane in it's fluidity

Back 3

Steroid cholesterol

Front 4

Penetrate hydrophobic core of the lipid bilayer

Back 4

Integral proteins

Front 5

Appendages loosely bound to the surface of the membrane - exposed parts of integral proteins

Back 5

Peripheral proteins

Front 6

Ogliosaccharides covalently bonded to lipids - markers that distinguish from one cell to another

Back 6

Glycolipids

Front 7

Lets hydrophilic substances pass through the lipid bilayer to avoid contact; spans the membrane; some have a hydrophilic channel, others hold onto the passengers and move them across

Back 7

Transport Proteins

Front 8

Tendency for molecules to spread out into the available space - thermal energy absorbed from environment

Back 8

Diffusion

Front 9

In the absence of other forces, a substance will diffuse to where it is less concentrated - spontaneous process because it decreases free energy

Back 9

Concentration Gradient

Front 10

Diffusion of a substance across a biological membrane - does not have to expend energy to make it happen

Back 10

Passive Transport

Front 11

Solution with a higher concentration of solutes

Back 11

Hypertonic

Front 12

Solution with a lower solute concentration

Back 12

Hypotonic

Front 13

Solutions of equal solute concentration

Back 13

Isotonic

Front 14

Diffusion of water across a selectively permeable membrane - a special case of passive transport

Back 14

Osmosis

Front 15

The control of water balance; animals and other organisms have rigid cell walls have this adaptation

Back 15

Osmoregulation

Front 16

Elastic plant cell wall is very firm; healthy state for most plant cells

Back 16

Turgid

Front 17

Limp; plant cells and their surroundings are isotonic - no tendency for water to enter - causes plant to wilt

Back 17

Flaccid

Front 18

Plasma membrane pulls away from the wall - usually lethal

Back 18

Plasmolysis

Front 19

Polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane

Back 19

Facilitated diffusion

Front 20

Water channel proteins; facilitates the massive amounts of diffusion

Back 20

Aquaporins

Front 21

Stimulus causes them to open or close - chemical - a substance other than the one to be transported

Back 21

Gated channels

Front 22

Pumping a molecule across a membrane against its gradient - must expend metabolic energy

Back 22

Active transport

Front 23

Exchanges sodium for potassium across the plasma membrane of animal cells

Back 23

Sodium-potassium pumps

Front 24

Voltage across a membrane - -50 to -200 millivolts

Back 24

Membrane potential

Front 25

A chemical force and an electrical force drive the diffusion of ions across a membrane acting on an ion - resulting voltage used to do work

Back 25

Electrochemcal gradient

Front 26

Transport protein that generates voltage across a membrane - against concentration gradient - can be a chemical or an electrical gradient

Back 26

Electrogenic pump

Front 27

Actively transports hydrogen ions (protons) out of the cell - more acidic outside - rush back through contrasport protein

Back 27

Proton pump

Front 28

Single ATP-powered pump that transports a specific solution can indirectly drive the active transport of several other solutes in a mechanism

Back 28

Contrasport

Front 29

Fusion of vesicles with the plasma membrane

Back 29

Exocytosis

Front 30

Cell takes in macromolecules and particulate matter by forming new vesicles from the plasma membrane

Back 30

Endocytosis

Front 31

Cell engulfs a particle by wrapping pseduopodia around it and packing it within a membrane - enclosed sac large enough to be classified as a vacuole

Back 31

Phagocytosis

Front 32

Cell "gulps" droplets of extracelluluar fluid into tiny vesicles

Back 32

Pinocytosis

Front 33

Specific receptor sites exposed to extracellular fluid - triggers vesicle formulation by ligands

Back 33

Receptor-mediated Endocytosis

Front 34

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

Back 34

Ligands