Choose the correct term.
A passive process, diffusion/osmosis is the movement of solute molecules from an area of greater concentration to an area of lesser concentration.
diffusion
A solution surrounding a cell is hypertonic if:
a. it contains fewer nonpenetrating solute particles that the interior of the cell.
b. it contains more nonpenetrating solute particles that the interior of the cell.
c. it contains the same amount of nonpenetrating solute particles as the interior of the cell.
b. A hypertonic solution contains a higher concentration of nonpenetrating solute particles than the interior of the cell.
Which of the following would require input of energy?
a. diffusion
b. filtration
c. osmosis
d. vesicular transport
d. vesicular transport
Choose the correct term:
In pinocytosis/phagocytosis, parts of the plasma membrane and cytoplasm extend and engulf a relatively large or solid material.
phagocytosis
Choose the correct term:
In active/passive processes, the cell provides energy in the form of ATP to power the transport process.
active
Select all that apply:
Molecular motion
a. reflects the kinetic energy of molecules
b. reflects the potential energy of molecules
c. is ordered and predictable
d. is random and erratic
a. reflects the kinetic energy of molecules
and
d. is random and erratic
Select all that apply:
Speed of molecular movement
a. is higher in larger molecules
b. is lower in larger molecules
c. increases with increasing temperature
d. decreases with increasing temperature
e. reflects kinetic energy
b. is lower in larger molecules
c. increases with increasing temperature
e. reflects kinetic energy
Summarize the results of activity 3. List and explain your observations relative to the tests used to identify diffusing substances, and the changes in sac wight you observed.
Sac 1 containing 40% glucose suspended in distilled water.
Glucose diffused down the concentration gradient from the sac into the water. Water moved via osmosis into the sac. This is why Benedict's test was positive for reducing sugars in the water and explains the increase in the sac's mass.
Summarize the results of activity 3. List and explain your observations relative to the tests used to identify diffusing substances, and the changes in sac wight you observed.
Sac 2 containing 40% glucose suspended in 40% glucose
Insignificant change in the mass of the sac, likely due to the wet while soaking. No net diffusion or osmosis.
Summarize the results of activity 3. List and explain your observations relative to the tests used to identify diffusing substances, and the changes in sac wight you observed.
Sac 3 containing 10% NaCl suspended in distilled water
Diffusion of Na+ and Cl- ions down the concentration gradient from inside the sac into the beaker water. Osmosis of water into the sac. This accounts for the positive test for silver chloride and the increase in sac mass.
Summarize the results of activity 3. List and explain your observations relative to the tests used to identify diffusing substances, and the changes in sac wight you observed.
Sac 4 containing 40% sucrose and Congo red dye suspended in distilled water
The Congo red dye did not diffuse into the beaker water as the water remained clear and colorless. The sucrose did not diffuse as Benedict's test was negative. Water moved into the sac via osmosis resulting in an increase in sac mass.
What single characteristic of the selectively permeable membranes used in the laboratory determines the substances that can pass through them.
The membrane pore cell size.
In addition to this characteristic, what other factors influence the passage of substances through living membranes?
Molecular size, polarity/molecular charge, concentration gradients.
Also, carrier molecules and active transport systems influence the passage through living membranes.
A semipermeable sac filled with a solution containing 4% NaCl, 9% glucose, and 10%albumin is suspended in a solution with the following composition: 10% NaCl, 10% glucose, and 40% albumin. Assuming that the sac is permeable to all substances except albumin, state if the following will move out of the sac, move into the sac, or not move.
glucose
Glucose will move down its concentration gradient into the sac.
A semipermeable sac filled with a solution containing 4% NaCl, 9% glucose, and 10%albumin is suspended in a solution with the following composition: 10% NaCl, 10% glucose, and 40% albumin. Assuming that the sac is permeable to all substances except albumin, state if the following will move out of the sac, move into the sac, or not move.
water
Water will move down its concentration via osmosis out of the sac into the surrounding fluid.
A semipermeable sac filled with a solution containing 4% NaCl, 9% glucose, and 10%albumin is suspended in a solution with the following composition: 10% NaCl, 10% glucose, and 40% albumin. Assuming that the sac is permeable to all substances except albumin, state if the following will move out of the sac, move into the sac, or not move.
albumin
Albumin will not move as it cannot permeate the sac.
A semipermeable sac filled with a solution containing 4% NaCl, 9% glucose, and 10%albumin is suspended in a solution with the following composition: 10% NaCl, 10% glucose, and 40% albumin. Assuming that the sac is permeable to all substances except albumin, state if the following will move out of the sac, move into the sac, or not move.
NaCl
Will move down its concentration gradient into the sac.
What determines whether a transport process is active or passive?
If energy is required to facilitate the transport process, it is active transport.
Determine if the following describes active or passive process.
the movement of fats and respiratory gasses though the plasma membrane.
passive process
Determine if the following describes active or passive process.
phagocytosis and pinocytosis
active process
Determine if the following describes active or passive process.
osmosis, simple diffusion, and filtration
passive process
Determine if the following describes active or passive process.
may occur against concentration and/or electrical gradients
active process
Determine if the following describes active or passive process.
uses hydrostatic pressure or molecular energy as the driving force
passive process
Determine if the following describes active or passive process.
moves ions, amino acids, and some sugars across the plasma membrane
active processes
Define selective permeability.
a property of a membrane in which some molecules can pass, while others cannot, whether by diffusion or active transport.
Define diffusion.
movement of molecules from an area of higher concentration to an area of lower concentration.
Define simple diffusion.
movement of a substance down its concentration gradient through a semipermeable membrane due to the kinetic energy and motion of the molecule.
Define facilitated diffusion.
passive transport of a substance with the help of a carrier molecule down a concentration gradient.
Define osmosis.
movement of water down its concentration gradient across a selectively permeable membrane.
Define filtration.
passive transport of solvent and solute through a membrane driven by hydrostatic pressure.
Define vesicular transport.
active transport (requiring ATP) that occurs via membranous sacs (vesicles), which surround the material being transported.
Define endocytosis.
vesicular transport of substances from outside of a cell into the cell.
Define exocytosis.
vesicular transport of substances to be excreted from the cell from inside the cell to the external environment.
Define pinocytosis.
Cell drinking/fluid-phase endocytosis. Cell "gulps" a drop of extracellular fluid containing dissolved molecules in a nonspecific process.
Define phagocytosis.
Cell eating. Cell engulfs a relatively large or solid material such as a clump of bacteria, cell debris, or inanimate particles.