Physio Ch 6 LS

Some ions move across a membrane using ion channel proteins that are open all the time. Others use ___ ion channel proteins, which have the ability to open and close.

gated

No charge in volume will occur in a cell placed in a(n) ___ solution.

isotonic

The difference in charge between the inside and outside of a cell is the:

membrane potential

Another term for cell membrane is ___ membrane.

plasma

What is another name for the cell membrane?

plasma

Which ion exerts the greatest effect on resting membrane potential?

potassium

A hormone, neurotransmitter or paracrine messenger must first bind to a specific ___ on the target cell.

receptor

Membranes exhibit ___ in that only some molecules are allowed to pass through the membrane.

selective permeability

Some molecules are permitted to cross from one side of the plasma membrane to the other, while other molecules are not allowed to cross the membrane. Therefore the plasma membrane exhibits ___ ___ .

selectively permeability

The process of ___ occurs when molecules move down a concentration gradient due to random molecular motion

diffusion

The process of ___ occurs when molecules move down a concentration gradient due to random molecular motion.

diffusion

The random molecular movement of molecules from an area of higher concentration to an area of lower concentration is defined as:

diffusion

The ___ environment is comprised of fluid compartments containing dissolved molecules and a matrix of polysaccharides and proteins that give form to the tissues.

extracellular

Some cells can communicate directly with each other through ___ , where signaling molecules diffuse through the cytoplasm of adjacent cells.

gap junctions

Choose all that apply to active transport.

- Molecules move from an area of lower concentration to an area of higher concentration - Requires expenditure of metabolic energy in the form of ATP

Extracellular matrix is comprised of:

- collagen fibers - elastin fibers - ground substance

Junctions between adjacent epithelial cells, through which paracellular transport is limited are

- desmosomes - tight junctions - adherens junctions

Choose the processes that are considered bulk transport.

- exocytosis - endocytosis

Which of the following substances will only cross a plasma membrane using facilitated diffusion?

- glucose

Choose the components that can be found in the extracellular environment.

- polysaccharides - dissolved molecules - fluid - proteins

Choose the characteristics of facilitated diffusion.

- powered by thermal energy - uses a carrier protein - passive transport process

The charge difference between the inside and outside of a cell that is not sending any impulses is known as its ___ ___ ___ .

- resting membrane potential

Choose the characteristics that carrier proteins and enzymes have in common.

- saturation - specificity - competition

Active transport is characterized by:

- the requirement of ATP - Movement of molecules against their concentration gradient

In the NA+/K+ pump, ___ molecules of sodium are transported and ___ molecules of potassium are transported in each cycle.

-3 -2

___ are ions with a negative charge, and ___ are ions that have positive charge.

-Anions - Cations

Match the type of transport with the direction of transport. -Antiport -Symport

-Antiport; two different molecules are transported together in the opposite direction -Symport; two different molecules are transported together in the same direction

Match the cell to the solution:

-Isotonic; no change -Hypotonic; Swell (cell gains water) -Hypertonic: Dehydrated (cell loses water)

The membrane potential is a result of the inside of a cell membrane being ___ charged and the outside of a cell being ___ charged.

-Negatively -Positively

Choose whether each molecule is anion or cation.

-Phosphate; anion -calcium; cation

A solution consists of the ___ and ___ .

-Solvent -Solutes

The rate of diffusion through a membrane is dependent upon:

-The temperature of the solution - the permeability of the membrane - the steepness of the concentration gradient - the surface area of the membrane

Put the steps of the pathway in order to maintain homeostasis of blood osmolality

1) dehydration occurs 2) osmoreceptors detect an increase in blood osmolality 3) the person becomes thirsty and ADH is secreted 4) ECF water volume is increased through ingestion of fluids and conservation of water in the kidneys 5) osmolality decreases

Match the correct proportion of fluid in each compartment:

20% - Blood plasma 80% - interstitial fluid

Match the specific type of membrane transport, with its general mechanism.

CARRIER-MEDIATED TRANSPORT; Facilitated diffusion, active transport NON-CARRIER MEDIATED TRANSPORT; Simple diffusion, osmosis

The ___ is comprised of protein fibers and a gel-like ground substance.

Extracellular fluid

True or false: most of the fluid in the body is located within the extracellular compartment.

FALSE

True or false: passive transport requires metabolic energy.

FALSE

True or false: the sodium potassium pump helps to maintain resting membrane potential by moving equal amounts of sodium and potassium across the cell membrane.

FALSE

___ is the specific term referring to the net movement of water across a selectively permeable membrane.

Osmosis

True or false: tonicity describes the effect of a solution on the movement of water.

TRUE

Moving molecules against their concentration gradient requires ATP and is a form of ___ transport.

active

Paracellular transport is the movement of substances:

between adjacent cells

Endocytosis and exocytosis are c=mechanisms of ___ transport.

bulk

Endocytosis and exocytosis are mechanisms of ___ transport.

bulk

What is the characteristic, shared by enzymes and carrier proteins, in which the proteins interact only with certain molecules?

specificity

The effect of a solution on the osmotic movement of water is:

tonicity

The potential difference of a cell is measured in ___ .

voltage