chapter 6 study guide

25. Describe in detail the activity of the Sodium/Potassium pump. In which body cells are these proteins found? Important details include: ions, and their numbers, direction of their movement, and cost.

2K+ goes in to the membrane the 3Na+ move out costing 1 ATP

The value of the resting membrane potential in a typical neuron is approximately _________.

-70mV

What is the value of the "Resting Membrane Potential" (RMP) in a typical neuron? (include units)

-70mV

26. Draw a simple diagram of the sodium/potassium pump in action (be sure to include the ions, their numbers, the direction they are moved, and the ATP used).

.

A dehydrated patient needs a saline solution in order to be rehydrated. Unfortunately the hospital is poorly stocked with saline solutions. The nurse was asked by the doctor to mix up 1 L of a 0.45% saline solution using NaCl and distilled water. How would she do this? What is the osmolarity of this solution?

.

18. What aspects of channel proteins can be considered advantageous? There are multiple advantages. What about them is a disadvantage?

.A- only allow specific proteins, some are gated D- Non-gated channels are leak-channels which cause the loss of some ions

21. What aspects of facilitated diffusion as a process can be considered advantageous? Disadvantageous? Defend your statements.

.A:no ATP required D:can only move molecules down a concentration gradient

20. Explain how protein-carriers are different from channel proteins. advantages and disadvantages

.channel proteins-ions channel proteins that can only go down concentration gradient Protein carriers-facilitative or active diffusion, active diffusion can go against the concentration gradient but requires ATP.

10. What conditions must be met in order for osmosis to occur?

1) different concentrations of water on each side of the membrane 2)membrane must be permeable to water but not the solute

11. What is the osmotic concentration of the ECF? (include units)

300mOsm

The Na+/K+ ATPase, pumps (this number of) ________ Na+ ions ________ (into/out of) the cell and (this number of) ________ K+ ions ________ (into/out of) the cell.

3Na+ ions out the cell 2K+ ions into the cell

Hyperosmotic solutions A) have higher concentrations of solutes than hyperosmotic solutions. B) have the same concentration of solutes as hyperosmotic solutions. C) have lower concentrations of solutes than hyperosmotic solutions.

A

If a 10% sucrose solution is separated from a 20% sucrose solution by a membrane impermeable to sucrose, in which direction will net movement of water occur? A) from the 10% sucrose solution to the 20% sucrose solution only B) from the 20% sucrose solution to the 10% sucrose solution only C) from the 10% sucrose solution to the 20% sucrose solution and from the 20% sucrose solution to the 10% sucrose solution D) There will be no net movement of water in this case. E) None of the answers are correct.

A

Permeability is a property of ______. A) membranes, B) ions, C) solutes, D) solvents, E) proteins.

A

The movement of molecules against their concentration gradient is _________________. A) active transport, B) passive transport.

A

The movement of molecules that requires ATP is ____________. A) active transport, B) passive transport.

A

The process that moves oxygen into / out of a cell is ____________________. A) simple diffusion, B) facilitated diffusion, C) active transport, D) both A and B, C) A, B and C.

A

Which of the following molecules can move across the phospholipid bilayer by simple diffusion? A) lipids B) oxygen C) sodium D) lipids and sodium E) lipids, sodium, oxygen.

A

Which of the following moves solutes in an aqueous solution from an area of high solute concentration to an area of low solute concentration? A) only facilitated diffusion B) only osmosis C) only primary active transport D) both facilitated diffusion and osmosis E) None of the answers are correct.

A

____________________ is a form of carrier-mediated transport. A) simple diffusion, B) facilitated diffusion, C) both A and B, C) neither A nor B.

B

15. What aspects of simple diffusion could be considered an advantage? What aspects of simple diffusion could be considered a disadvantage? Defend your statements.

A- no ATP used D-cant go against the concentration gradient

Red blood cells with an internal osmolarity of 300 mOsM are placed in the following solutions. Designate each solution according to its osmolarity and tonicity, and explain what happens to the cells and why. A. 200 mOsM NaCl B. 400 mOsM urea C. 100 mOsM urea plus 200 mOsM NaCl D. 300 mOsM urea E. 300 mOsM NaCl F. 200 mOsM urea plus 300 mOsM NaCl G. 400 mOsM NaCl

A. Hyposmotic, hypotonic. The cell swells. By Rule 5 in Table 5.8 in the chapter, hyposmotic solutions are always hypotonic, because the intracellular solutes are mainly nonpenetrating (Rule1) thus there will be a net flow of water into the cell. B. Hyperosmotic, hypotonic. The cell swells. Urea is a penetrating solute, so some urea will move into the cell down its concentration gradient. This will increase the osmolarity inside the cell, causing a net flow of water into the cell. C. Isosmotic, hypotonic. The cell swells. Urea is a penetrating solute, so there will be a net movement of urea into the cell, raising the osmolarity and causing a net flow of water into the cell. D. Isosmotic, hypotonic. The cell swells. Urea will penetrate the cell, raising the osmolarity and causing a net flow of water into the cell. E. Isosmotic, isotonic. No change in cell size. Sodium and chloride are nonpenetrating solutes ,so there will be no net ion flow across the membrane. Because there is no osmotic pressure, there will also be no net flow of water. F. Hyperosmotic, isotonic. No change in cell size at equilibrium. Initially water leaves the cell due to the higher osmolarity outside the cell. Then, because there is a concentration gradient for urea, urea will enter the cell, increasing its osmolarity, and bringing some water into the cell. The nonpenetrating solute concentrations in cell and solution initially are equal, therefore there will be no net movement of water at equilibrium. G. Hyperosmotic, hypertonic. The cell shrinks. There are no penetrating solutes, and water exits due to the higher osmolarity.

17. List the important molecules that cross the cell membrane by diffusion through channel proteins.

Na+ and K+

Advantage and disadvantage of active transport

A:can move from low concentration to high against gradient D:requires ATP

"Tends to create an equilibrium state" describes ______________. A) active transport, B) passive transport.

B

A cell that is permeable to Solute X is placed into solution containing a higher concentration of X. Diffusion occurs until equilibrium is attained. At this time, A) there is no further movement of Solute X across the membrane. B) there is no further change in concentration of Solute X. C) Both of the statements are correct. D) Neither of the statements is correct.

B

Compared to the outside of a resting cell membrane, the inside is: A) positively charged. B) negatively charged. C) electrically neutral. D) continuously reversing its electrical charge. E) positively charged whenever the sodium-potassium pump is active.

B

Generally, the movement of molecules from an area of high concentration to an area of low concentration is a type of _____. A) active transport, B) passive transport.

B

If a 10% sucrose solution is separated from a 20% sucrose solution by a membrane permeable to sucrose, in which direction will net diffusion of sucrose take place? A) from the 10% sucrose solution to the 20% sucrose solution B) from the 20% sucrose solution to the 10% sucrose solution C) from the 10% sucrose solution to the 20% sucrose solution and from the 20% sucrose solution D) neither from the 10% sucrose solution to the 20% sucrose solution nor from the 20% sucrose solution to the 10% sucrose solution E) There will be no diffusion in this case.

B

Passive transport refers to a process that requires A) no energy at all. B) no cellular energy. C) no pressure gradient. D) no concentration gradient. E) no electrical gradient.

B

The concentration of calcium inside a cell is 0.3%. The concentration of calcium outside the cell is 0.1%. How could the cell transport even more calcium to the inside? A) passive transport B) active transport C) osmosis D) exocytosis E) All of the answers are correct.

B

The membrane proteins that change shape and bind with specific molecules to transport them across the cell membrane are ________. A) gated ion-channels, B) carrier proteins, C) aquaporins, D) ion channels, E) all of these.

B

The process that moves glucose into / out of a cell (for most cells) is _______________. A) simple diffusion, B) facilitated diffusion, C) both A and B, C) neither A nor B.

B

The term "cellular energy" indicates any biological process requiring: A) energy in any form, B) ATP, C) thermal energy, D) chemical energy, E) thermal energy and chemical energy.

B

What are the two extracellular fluid compartments in the body? A) intracellular and plasma, B) plasma and interstitial, C) interstitial and intracellular, D) plasma and the fluid portion of the blood, E) None of the answers are correct.

B

Which body fluid compartment contains high levels of K+ and proteins? A) plasma only, B) interstitial fluid only, C) intracellular fluid only, D) both plasma and intracellular fluid, E) both plasma and interstitial fluid

B

Which of the following is NOT true of diffusion in the human body? A) Diffusion occurs faster at higher temperatures. B) Smaller molecules take longer to diffuse than larger ones. C) Net movement of molecules occurs until the osmolarity is equal. D) Diffusion is rapid over short distances and slower over longer distances.

B

When the kidney goes into failure, one of the signs that doctors will see is that red blood cells will crenate (shrivel up). Why does this happen in kidney failure? What process is occurring to the blood cells?

Because the kidney is failing to filter particles out of the blood effectively, the plasma becomes hypertonic or hyperosmotic in comparison to the intracellular compartment of the blood cell. Since the cell membrane is impermeable to the ions, but permeable to water, water will leave the cell to try to balance the tonicity and osmolarity with the plasma and in the process the cell will shrink.

"The use of ATP to move molecules" describes _______________. A) simple diffusion, B) facilitated diffusion, C) primary active transport, D) both A and B, C) A, B and C.

C

All of the following are types of carrier-mediated transport EXCEPT one. Identify the exception. A) facilitated diffusion, B) primary active transport, C) simple diffusion, D) secondary active transport

C

Facilitated diffusion and active transport differ in that A) facilitated diffusion uses cell membrane proteins to move substances, whereas active transport does not. B) facilitated diffusion uses a substrate to bind to a protein carrier, whereas active transport does not. C) ATP is necessary for active transport, but not for facilitated diffusion. D) facilitated diffusion moves water across the cell membrane, whereas active transport does not. E) potential energy is required for active transport but not for facilitated diffusion.

C

Hyposmotic solutions: A) have higher concentrations of solutes than hyperosmotic solutions. B) have the same concentration of solutes as hyperosmotic solutions. C) have lower concentrations of solutes than hyperosmotic solutions.

C

Saturation with respect to transport occurs when: A) molecules are moved by the use of vesicles, B) the energy required to move molecules results from a high-energy bond, C) a group of carrier proteins is operating at its maximum rate, D) a preference of a carrier protein for a substance is demonstrated based on the differing affinities of the carrier for the substrates, E) a carrier molecule has the ability to transport only one molecule or a group of closely related molecules.

C

The means by which a cell transports large molecules out of the cell is called ______. A) phagocytosis, B) endocytosis, C) exocytosis, D) diffusion, E) active transport.

C

Which of the following statements about the resting membrane potential is TRUE? A) It is normally equal to zero volts. B) The inside of the membrane is positively charged compared to the outside. C) It results, in part, from the concentration gradients for Na+ and K+. D) It is due in part to the presence of extracellular proteins.

C

Which property of diffusion best helps explain the necessity of the circulatory system in multicellular organisms? A) Molecules move from an area of higher concentration to an area of lower concentration. B) Diffusion can take place in an open system or across a partition that separates two systems. C) Diffusion is rapid over short distances but much slower over long distances. D) Diffusion rate is inversely related to molecule size.

C

Which membrane protein is responsible for maintaining the concentration of this ion?

Na+/K+ pumps

13. List the factors that influence the rate at which molecules diffuse. Explain how changes in each will affect the rate of diffusion (that is does an increase in the factor speed up or slow down the rate).

Concentration -its faster permeability -small molecules move faster temperature - hotter molecules move faster

"The movement of molecules from an area of high concentration to an area of low concentration" describe _____________. A) simple diffusion, B) facilitated diffusion, C) primary active transport, D) both A and B, C) A, B and C.

D

5. Provide a mechanistic explanation as to why diffusion occurs. In other words at the molecular level why does diffusion occur?

Diffusion occurs because molecules are always moving inside solvent. Diffusion occurs from a high concentration to a low, to achieve a relatively equal concentration in both areas

Membrane protein "pores" that can be opened and closed to allow specific molecules through are generally referred to as ________ channels. A) actuated, B) regulatory, C) variable, D) gated, E) none of these.

D

Which of the following statements about the Na+/K+ pump is FALSE? A) It transports Na+ out of the cell and K+ into the cell. B) It is present in neurons. C) Its activity requires the expenditure of metabolic (cellular) energy. D) It transports Na+ and K+ in a 1:1 ratio.

D

Which body fluid compartment contains high levels of Na+, Cl-? A) plasma only, B) interstitial fluid only, C) intracellular fluid only, D) both plasma and intracellular fluid, E) both plasma and interstitial fluid

E

27. Where is most of the Sodium found in the body?

ECF

28. Where is most of the Potassium found in the body?

ICF

1. With respect to the functional compartmentalization of the body, what are the two large fluid-filled spaces? ______________________________ ________________________________. Which of these contains more fluid? (circle one to indicate it contains more fluid). About how much of the fluid (%) in the body is contained within each compartment?

ICF 64% and ECF33%

There are two solutions separated by a semipermeable membrane. Solution a is 0.3 M glucose, and solution b is 0.15 M NaCl. Will there be a net flow of water across this membrane? Why or why not?

In osmoles, solution a is 0.3 OsM and solution b is 0.3 OsM (because sodium and chloride dissociate into separate particles). The solutions are isosmotic, and there is no net water flow.

There are two solutions separated by a semipermeable membrane. Solution a is 0.2 M NaCl and solution b is 0.1 M CaCl2. Will there be a net flow of water across the membrane? Why or why not?

In osmoles, solution a is 0.4 Osm and solution b is 0.3 Osm. Solution a is hyperosmotic, so there will be a net flow of water into solution a until equilibrium is established.

30. Which ion is MOST important in determining the RMP? (We also discuss this in lab 2.1). Explain how it is that it contributes most to the RMP. Which membrane protein is responsible for maintaining the concentration of this ion?

K+ pumps more important RM is more permeable to K+ many leak channels so the cell must Na+/K+ pumps t keep cell at the correct levels .

Cells of the intestine are very permeable to water while some cells of the kidney tubule are not at all permeable to water. Can you suggest some ways these two types of cells might be structurally different from each other?

Kidney cells may have fewer aquaporins channels through which water can pass.

How are molarity and osmolarity different? What property of salts necessitates this distinction? How does this property affect the behavior of water?

Molarity is the number of molecules per liter of solution, while osmolarity is the number of independent particles per liter. The ionization of salt in water illustrates the importance of this distinction: one mole of sodium chloride dissociates to produce a total of two moles of particles (one mole Na+ and one mole Cl-), or two osmoles. Osmosis is diffusion of water. A one molar solution of sodium chloride (two osmolar) produces higher osmotic pressure than a one molar solution of glucose, which does not dissociate.

4. Define "net diffusion", explain how it is different from just "diffusion"

Movement of moles from a high concentration to a lower concentration (diffusion is random movement of molecules)

8. What is Osmolarity? How is it different from a Molarity.

Osmolarity is mole of particles per liters of solution as molarity is mole of solute per liter of solution

Define osmolarity and tonicity. How are they similar? How are they different?

Osmolarity refers to the concentration of individual particles in solution. Tonicity describes a solution and what it does to cell volume. similar- both are related to particles in solution. They are different in that osmolarity depends only on the total concentration of particles in solution, and tonicity depends on the nature of the particles, as well as on the concentration of the different particles.

Evaluate the validity of this statement: "The extracellular and intracellular fluid compartments have a stable solute composition that is in equilibrium."

Statement is only partially true. The components are stable but they are not at equilibrium

Which of the following might increase the rate of simple diffusion across a cell membrane? A) a decrease in the surface area of the membrane B) a decrease in the concentration gradient C) a decrease in membrane permeability D) a decrease in membrane thickness

a

19. Define facilitated diffusion. List the important molecules that are moved by facilitated diffusion.

a carrier mediated transport system that utilizes kinetic energy and carrier proteins to move molecules down a gradient. Ex: GLUT2,urea,amino acids

6. Define tonicity.

a solution and the effects it has on a cell

Define hypertonic.

a solution that causes cells to decrease in volume

Define hypotonic

a solution that causes cells to increase in volume

3. The proteins that are almost always present in a plasma membrane that allows water to pass freely are called

aqua porines

32. Define electricity (or electric current) and explain how it applies to a cell.

current movement of charged particles

A specific carrier protein or ion channel would generally allow a diversity of molecules to pass, or be passed through the plasma membrane. A) True, B) False.

false

29. Define the term "Resting Membrane Potential" (RMP)

membrane potential of a cell at rest

14. Define simple diffusion. Make a list of important molecules that move by simple diffusion (be specific).

molecules move high to low directly across the bilayer ex: O2, CO2, testosterone, estrogen, cortasol

7. Define osmosis.

net diffusion of water through a semipermeable membrane

2. List the 2 major sub-compartments of the extracellular fluid compartment of the body. About how much of the ECF does each contain (%)?

plasma 20% tissue fluid 80%

Define isotonic

same osmolarity between a cell and the solution it is in. No net movement

23. Describe the process of exocytosis. List some products transported by exocytosis. What about exocytosis could be considered an advantage?

the mean by which a cell transport large molecules out of the cell into the Extracellular environment Polypeptides and Proteins. Exocytosis provides bulk transport out of the cell, this could be considered an advantage.

Define passive transport.

the transport of molecules across a semipermeable membrane using carrier proteins NOT ATP

12. Define active transport

transport of molecule across a semipermeable membrane from low to high (against concentration gradient) using ATP and carrier proteins

A specific carrier protein or ion channel would generally only allow specific molecules to pass, or be passed through the plasma membrane. A) True, B) False

true

16. Briefly explain what protein-mediated transport is.

uses carrier proteins to transport molecules, carriers change shape to move molecules.