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Quizlet for Mr. McCormick's Test on Chapter 7 (Membranes / Transport) on Monday 10/9/12.


___________ Transport does not cost a cell any ATP.


One of the main reasons that _________ transport within the cell is able to happen, is because all molecules have kinetic energy and are moving.


Phenomena in which molecules distribute themselves from areas of high to low concentration until equilibrium is attained


State of equal distribution of molecules

Concentration Gradient

Name for the spectrum of molecule concentrations in an area


If something is moving up a concentration gradient, then it is moving towards an area of (high / low) concentration.


Chemicals produced in very very small quantities that drastically change the behavior of an organism


Diffusion of water across a membrane


Unless otherwise specified, a given membrane in a problem is permeable only to _________.


A solution is __________ if it has an equal concentration of solute to a cell inside of it.


A solution is ___________ if it has a higher concentration of solute than a cell inside of it.


A solution is __________ if it has a lower concentration of solute than a cell inside of it.


True or False:
Water does not flow between an isotonic solution and a cell within the solution because the water concentrations of the two are already equal to one another.


In a(n) _________ solution, the water inside of a cell will flow in and out at a constant rate.


The bursting of an animal cell

Turgor Pressure

While plant cells do not burst because of their cell wall, they will experience an increase in _________ ____________ if put in a highly hypotonic solution.


Plasmolysis occurs in plant cells when the cells are exposed to a _______________ solution.


The peeling off of the cell wall by a plasma membrane in a plant cell when it is placed in a hypertonic environment


True or False:
During plasmolysis the organelles of a plant cell clump together.

Facilitated Diffusion

Name of process during which a protein embedded in a cell membrane aids in diffusion


Facilitated diffusion is a form of (active / passive) transport.

temperature size steepness

The rate of diffusion is affected by:
1) ______________
2) ___________ of molecules
3) _____________ of concentration gradient

selective permeability

The allowance of some substances to cross a membrane more easily than others.


Most abundant lipids in most membranes


A molecule that has both hydrophobic and hydrophilic regions can be described as ______________.


The plasma membrane of a cell is (rigid / fluid).


A membrane is held together mainly by ____________ interactions.

unsaturated hydrocarbon tails

A membrane will maintain its fluidity for longer if it has more _____________ _____________ ____________.


"Temperature buffer" in a membrane


True or False:
Cholesterol can make a membrane less fluid by restricting phospholipid movement.


True or False:
Cholesterol can make a membrane more fluid by disrupting the close packing of phospholipids.


Membranes must remain ___________ to work properly.

integral peripheral

The two main types of membrane proteins are ___________ proteins and ____________proteins.


___________ proteins penetrate the hydrophobic core of the lipid bilayer.


Type of integral protein; spans the entire membrane

nonpolar amino acids

The hydrophobic region of an integral protein consists of one or more stretches of ___________ __________ _________.

α helices

Amino acids in the hydrophobic region of integral proteins are usually coiled into ___ ___________.

aqueous solutions

The hydrophilic regions of an integral protein are exposed to ___________ ____________ on either side of the membrane.

peripheral proteins

____________ ___________ are not embedded at all in the lipid bilayer.


Peripheral proteins are loosely bound to the __________ of the membrane and are often exposed to parts of integral proteins.


On the cytoplasmic side of a membrane, many proteins are held in place by the ________________.

extracellular matrix

On the extracellular side of a membrane, many proteins are held in place by fibers of the ________________ __________.


Function of membrane protein:
Spans the membranes and provides a hydrophilic channel for certain solutes to pass through


Function of membrane protein:
Moves substances by changing shape

Signal Transduction

Function of membrane protein:
Recognizes chemical messengers outside of the cell and relays messages to the inside of the cell so that certain chemical reactions can take place

Cell-Cell Recognition

Function of membrane protein:
Have attachments serves as identification tags to be recognized by membrane proteins of other cells

Intercellular Joining

Function of membrane protein:
Hook to other proteins of its kind in junctions


Type of molecule crucial in cell-cell recognition


Type of molecule used to designate A / B / AB / O blood group.


Most carbohydrates in the cell membrane are covalently bonded to...

A) lipids to form lipoproteins
B) proteins to form glycoproteins
C) proteins to form lipoproteins.


Molecules that start out on the inside face of the ER end up on the __________ face of the plasma membrane.


____________ molecules are hydrophobic and can therefore pass through the lipid bilayer of a membrane with ease.

transport proteins

Polar molecules avoid contact with hydrophobic membrane regions by passing through ___________ ___________.

channel protein

Type of transport protein that creates a hydrophilic pathway for polar molecules


Channel protein through which waters enters the cell

carrier protein

Type of transport protein that carries molecules across the cell membrane by changing shape


True or False:
Carrier proteins do not specifically function for one particular material.


the movement of molecules of any substance so that they spread out evenly into the available space

concentration gradient

Any substance will diffuse down its own _______________ _______________.


True or False:
In order to carry out diffusion, a cell needs to expend only a tiny bit of energy.


True or False:
No energy is used during diffusion.

Passive Transport

The movement of materials into / out of the cell without the use of energy.


Diffusion of water across a selectively permeable membrane


The ability of a cell to gain or lose water


True or False:
There will be no movement of water molecules when a cell is placed into an isotonic solution.


True or False:
There will be no net movement of water molecules when a cell is placed into an isotonic solution.


the control of water balance


Organisms without cell walls that live in hypo and hypertonic environments need to develop special adaptations for ______________.


Healthy state for most plant cells


If a plant cell is turgid, it is ______.


Plants cells in isotonic environments become ___________.


If a plant cell is flaccid, it is ______.

Facilitated Diffusion

Diffusion done with the help of transport proteins that span the membrane


True or False:
Water molecules can pass through the plasma membrane without the help of aquaporin.


Human organ that helps reclaim water from urine before it is excreted

Ion Channels

(AKA gated channels) channel proteins that open or close in response to a stimulus

Active Transport

The pumping of materials up a concentration gradient

Carrier Proteins

Type of transport proteins used in active transport


______ supplies energy for most active transport.


The inside of a cell is (positive / negative) in relation to extracellular fluid.


electrical potential energy

membrane potential

voltage across a membrane

-50 -200

Membrane potential ranges from ______ to _______ millivolts.

electrochemical gradient

The combination of forces acting on an ion

electrogenic pump

A transport protein that generates voltage across a membrane

sodium-potassium pump

Major electrogenic pump of animal cells

proton pump

Main electrogenic pump of plants, bacteria, and fungi

ATP Synthesis Cotransport

Important uses of proton pump:
1) _____ ____________
2) _____________


Whenever a molecule binds to a carrier protein, the shape or _____________ of the protein changes.

phosphate head

The (phosphate head / fatty acid tail) of a phospholipid is negative in charge and soluble in water.

phosphate heads

The (phosphate heads / fatty acid tails) of a phospholipid bilayer are exposed to aqueous solutions (e.g. extracellular fluid, cytoplasm).


True or False:
Proteins in a cell membrane are locked into place.


True or False:
When dealing with a membrane that has a phospholipid bilayer, only lipid-soluble items can pass through without the expenditure of ATP.


"Protein pores" designed to allow water molecules to pass through the cell membrane and increase their rate of entrance


Cell-cell recognition is dependent on __________.


True or False:
Only twins will have the same cell markers.


True or False:
Oxygen and CO2 can diffuse right through a cell membrane.

Nodes of Ranvier

Gaps on the myelin sheath that speed up impulses as they travel left to right

Schwann Cells

Cells that grow on the axon of a neuron to form the myelin sheath

Multiple Sclerosis

Degenerative disease in which the myelin sheath breaks down


Neuron part that picks up / receives messages


A ____________ neuron picks up messages and brings them to the central nervous system.


A ____________ neuron picks up messages and carries them to muscles (in turn making the muscle contract).

neurotransmitters vesicles

Once an impulse reaches the axon terminal of a neuron, ______________ are carried by __________ and are released.


If a neuron is at rest, then ___________ ions are inside the axon.


If a neuron is at rest, then ____________ ions are outside of the axon.

respond to stimuli

Gated ion channels are physically embedded in a neuron and are special because they _____________ ___ ____________.


A neuron at rest can be described as (polarized / depolarized).


As an impulse moves down a neuron, the neuron becomes (polarized / depolarized) and the "action potential" occurs.


After a neuron has been depolarized, ___________ ions should be concentrated outside of the axon.


After a neuron has been depolarized, ___________ ions should be concentrated inside of the axon.

active transport

After depolarization, a neuron must undergo a kind of ___________ ____________ to reestablish membrane potential.

Sodium Potassium Pump

Mechanism of active transport that returns neurons to membrane potential by moving displaced ions


At resting potential, ion channels are (open / closed).


True or False:
Both Sodium and Potassium ions are positively charged.

protein nucleic acid

Components inside of an axon that contribute to its negative charge:
___________ ____________


As a nerve impulse moves down a neuron, __________ ion gated ion channels open and cause neighboring channels to do the same.


The Sodium Potassium Pump helps __________ ions leave the cell.


The Sodium Potassium Pump helps __________ ions enter the cell.

3 2

In one cycle, a Sodium Potassium Pump will transport ____ sodium ions and _____ potassium ions


Once opened, ____________ gated channels cause vesicles in the axon terminal of a neuron to fuse with the membrane and release neurotransmitters.

diffusion synapse target

Neurotransmitters use ___________ to move across the ___________ between two adjacent neurons until their __________ is reached.

ACh esterase

Once ACh (a neurotransmitter in motor neurons) reaches its target receptors, the receptors will release _____ ___________ to cease the reaction with ACh.


process through which vesicles are released from the cell

myasthenia gravis

progressive auto-immune disease that breaks down ACh receptors


material used in poison arrow darts; binds to receptors and paralyzes victims (also used in surgery)


There are ___ main types of endocytosis.


During ____________, cells bring in "solid materials".


During ____________, cells bring in "liquid materials".

receptor mediated endocytosis

During ____________ ______________ ____________, materials bind to specific receptors on the outside of a cell, and then the cell proceeds to form a vesicle from the receptors and their attached materials.


Diffusion and pumping of materials into and out of the cell generally deals with ________-sized solutes.


Vesicles are used to transport ________-sized materials and solutes like polysaccharides and proteins.


True or False:
Endocytosis and Exocytosis do not require ATP.


A(n) _____________ is any molecule that binds specifically to a receptor site of another molecule. (e.g. LDLS)

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