BIO 360 - Exam 1- Chapter 5 Summary Questions

Question 1

Most solutes are concentrated in either one compartment or the other, creating a state of ______ ______.

Answer 1

chemical disequilibrium

Question 2

Cations and anions are not distributed equally between the body compartments, creating a state of ______ ______.

Answer 2

electrical disequilibrium

Question 3

Water moves freely between the cells and extracellular fluid, resulting in a state of ______ ______.

Answer 3

osmotic equilibrium

Question 4

The movement of water across a membrane in response to a concentration gradient is called?

Answer 4

osmosis

Question 5

We express the concentration of biological solutions as ______, the number of particles (ions or intact molecules) per liter of solution, in units of milliosmoles per liter (mOsM).

Answer 5

osmolarity

Question 6

______ of a solution describes the cell volume change that occurs at equilibrium if the cell is placed in that solution. Cells swell in ______ solutions and shrink in ______ solutions. If the cell does not change size at equilibrium, the solution is ______.

Answer 6

Tonicity / hypotonic / hypertonic / isotonic

Question 7

The osmolarity of a solution cannot be used to determine the tonicity of the solution. The relative concentrations of ______ ______ in the cell and in the solution determine tonicity. ______ ______ contribute to the osmolarity of a solution but not to its tonicity.

Answer 7

nonpenetrating solutes / Penetrating solutes

Question 8

In ______ ______, a pressure gradient moves a fluid along with its dissolved and suspended materials.

Answer 8

bulk flow

Question 9

The cell membrane is a selectively permeable barrier that restricts free exchange between the cell and the interstitial fluid. The movement of a substance across a membrane depends on the ______ of the membrane to that substance.

Answer 9

permeability

Question 10

____ ____ substances can diffuse through the phospholipid bilayer. Less lipid-soluble molecules require the assistance of a membrane protein or vesicle to cross the membrane.

Answer 10

Lipid-soluble

Question 11

______ transport does not require the input of energy.

Answer 11

Passive

Question 12

______ is the passive movement of molecules down a chemical (concentration) gradient from an area of ______ concentration to an area of ______ concentration. Net movement stops when the system reaches ______, although molecular movement continues.

Answer 12

Diffusion / higher / lower / equilibrium

Question 13

Diffusion rate depends on the ______ of the concentration gradient. Diffusion is ______ over long distances, is directly related to ______, and is inversely related to ______ ______.

Answer 13

magnitude / slow / temperature / molecular size

Question 14

Simple diffusion across a membrane is directly proportional to? Inversely proportional to?

Answer 14

membrane surface area, concentration gradient, and membrane permeability / membrane thickness

Question 15

Membrane proteins have four functional roles:
(1) structural proteins -
(2) membrane-associated enzymes
(3) receptor proteins
(4) transport proteins

Answer 15

(1) maintain cell shape and form cell junctions
(2) catalyze chemical reactions and help transfer signals across the membrane
(3) are part of the body’s signaling system
(4) move many molecules into or out of the cell.

Question 16

______ transport moves molecules ______ their concentration gradient and requires an outside source of energy.

Answer 16

Active / against

Question 17

In ______ active transport, the energy comes directly from ATP. ______ active transport uses the potential energy stored in a concentration gradient and is indirectly driven by energy from ATP.

Answer 17

primary (direct) / Secondary (indirect)

Question 18

The most important primary active transporter is the sodium-potassium-ATPase which pumps ____ out of the cell and ______into the cell.

Answer 18

Na+ / K+

Question 19

Most secondary active transport systems are driven by the ______ concentration gradient

Answer 19

sodium

Question 20

Large macromolecules and particles are brought into cells by phagocytosis or endocytosis.

Material leaves cells by ______.

When vesicles that come into the cytoplasm by ______ are returned to the cell membrane, the process is called ______ ______.

Answer 20

exocytosis / endocytosis / membrane recycling

Question 21

In receptor-mediated endocytosis, ligands bind to membrane receptors that concentrate in coated pits or caveolae.

Answer 21

–

Question 22

In ______, the vesicle membrane fuses with the cell membrane before releasing its contents into the extracellular space.

______ requires ATP.

Answer 22

exocytosis

Question 23

Molecules cross epithelia by moving between the cells by the ______ route or through the cells by the ______ route.

Answer 23

paracellular / transcellular

Question 24

Larger molecules cross epithelia by ______, which includes vesicular transport.

Answer 24

transcytosis

Question 25

Although the total body is electrically neutral, diffusion and active transport of ions across the cell membrane create an ______ gradient, with the inside of cells ______ relative to the extracellular fluid.

Answer 25

electrical / negative

Question 26

The electrical gradient between the extracellular fluid and the intracellular fluid is known as the ______ ______ ______ difference.

Answer 26

resting membrane potential

Question 27

The movement of an ion across the cell membrane is influenced by the ______ gradient for that ion.

Answer 27

electrochemical

Question 28

The membrane potential that exactly opposes the concentration gradient of an ion is known as the ______ ______.

Can be calculated using the Nernst equation.

Answer 28

equilibrium potential

Question 29

In most living cells, ______ is the primary ion that determines the resting membrane potential.

Answer 29

K+

Question 30

Changes in membrane permeability to ions such as K+, Na+, Cl- or Ca2+ alter membrane potential and create electrical signals.

Answer 30

–