BIO130H1 Chapter Notes - Chapter quiz7: Potassium Channel, Osmosis, Partition Coefficient

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Elux (net movement of stuf out of the cell) Difusion: spontaneous movement of stuf from high to low concentraion. Is exergonic and leads to increase in entropy. ******** this is the energy change across a membrane of a solute going from outside to inside the cell. For inside to out, switch the in and out concentraions in the equaion. When dealing with an ***electrolyte/ion***then you have an electrochemical gradient then you use this. Where z is the charge of the solute and deltae is the potenial diference (v) between sides. Which really means: (energy change)= (energy of concentraion gradient) + (energy of electric potenial gradient) Passes only if there is a concentraion gradient. Must pass through membrane either by dissolving in and going directly through it or by going through an aqueous pore. Pariion coeicient= the raio of a substance"s solubility in nonpolar solvent over polar (water) solvent (under condiions when the nonpolar and polar solvents are mixed together)

Related Questions

Question 1

Plasma membranes are selectively permeable. This means that

	A.	glucose cannot enter the cell.
	B.	the plasma membrane allows some substances to enter or leave a cell more easily than others.
	C.	plasma membranes must be very thick.

Question 2

Oxygen molecules O₂ crosse a plasma membrane by

	A.	passive transport
	B.	osmosis
	C.	active transport

Question 3

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

		A. energy and channel proteins; against (up)
		B. transport proteins that make channels ; down
		C. energy ; down

Question 4

When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will

		A. move to the side with lower water concentration
	B.	move to the side with higher water concentration
	C.	move to the side with lower solute concentration

Question 5

Kinetic energy differs from chemical energy in that

	A.	chemical energy is a particular form of kinetic energy.
	B.	kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules.
	C.	kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement.

Question 6

When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction.

	A.	exergonic; endergonic
	B.	endergonic; exergonic
	C.	spontaneous; exergonic

Question 7

When an enzyme catalyzes a reaction

		A. it raises the activation energy of the reaction.
		B. it lowers the activation energy of the reaction.
		C. it is used once and discarded.

Question 8

Which of the following statements regarding enzyme function is false?

		A. An enzyme's function depends on its three-dimensional shape.
		B. Enzymes are very specific for their substrates.
		C. Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction

BIOL 110 Principles of Biology

1.Describe the structure of a plasma membrane.

2.Define an amphipathic molecule and give an example.

3.Explain the difference between integral and peripheral proteins.

4.Describe the fluid-mosaic model of a membrane.

5.Identify and discuss the function of proteins located in the plasma membrane.

6.Explain the difference between glycoproteins and glycolipids.

7.Why can carbon form chemical bonds with so many elements?

8.Explain the meaning of concentration gradient as it pertains to movement of substances into and out of cells.

9.Explain diffusion and osmosis.

10.What molecule is thought to facilitate the movement of water molecules through a plasma membrane?

11.Explain the difference between active and passive transport across the plasma membrane. Provide examples that occur in the human body.

12.Explain the impact to a cell if placed in a hypertonic solution; include a definition of hypertonic solution and why the change occurs.

13.Identify a similarity and difference between facilitated transport and active transport. Do not state that both move substances across the membrane.

14.Explain the sodium-potassium pump and identify the type of membrane protein involved.

15.Identify and explain the process used by cells to secrete substances.

16.Explain the composition of a plant cell wall and how it differs from the cell wall of a prokaryotic cell.

17.Explain the plasmodesmata and identify the kingdom in which they are found.

18.Define energy and identify the two basic forms of energy.

19.Define entropy.

20.Define metabolism.

21.Explain the difference between exergonic and endergonic reactions.

22.What are coupled reactions and what roles can ATP serve in these reactions?

23.Explain the difference between oxidation and reduction reactions.

24.What is energy of activation?

25.What factors affect the speed of enzymatic reactions?

26.What is an electron transport chain?

27.What occurs at the active site of an enzyme?

28.Define enzymatic inhibition.

29.Define chemiosmosis.

30.Define vitamins and identify their function.

1. The plasma membrane of liver cells contains a glucose uniportthat transports glucose by facilitated diffusion. When the[glucose] is higher inside the liver cell than the [glucose]outside the liver cell, the glucose uniport will

A. couple the transport of glucose out of the cell to thehydrolysis of ATP

B. couple the transport of glucose into the cell to thehydrolysis of ATP

C. switch to a closed conformation, allowing no transport ofglucose

D. transport glucose out of the cell by passive transport

E. transport glucose in of the cell by passive transport

2. Unlike the positive charged ion shown in the middle diagramof figure 11-4B, K+ is higher in concentration inside the cell. Howwill the membrane potential of a cell at rest (shown in both themiddle and right-hand diagrams of Figure 11-4B) affect theelectrochemical gradient for K+?

A. The membrane potential will increase the electrochemicalgradient

B. The membrane potential will decrease the electrochemicalgradient

C. The membrane potential will have no effect on theelectrochemical gradient

3. Which of the following proteins carries out activetransport?

A. gluclose symport

B. Bacteriorhodopsin

C. ABC transporter

D. NA K pump

E. All of the above

4. Aquaporin will not transport Na+ ions because

A. Two asparagine residues in the channel prevent the passage ofNa+ ions by binding the oxygen of each water molecule as it passesby

B. Na+ ions are repelled by the positive charges at the entranceto the channel

C. Na+ ions cannot make contact with the carbonyl (C=O) groupson all four sides of the channel

D. The passage of Na+ ions is energetically unfavorable becauseone side of the channel is hydrophobic in nature

5. The acetylcholine receptor is different from other channelproteins we have discussed, such as the K+ leak channel,because

A. The acetylcholine channel is composed of a single polypeptiderather than multiple subunits

B. The acetylcholine channel transports Na+ ions against theconcentration gradient for sodium

C. The acetylcholine channel has a much smaller diameter thanother channel proteins

D. The acetylcholine channel transports ions with theirassociated shell of water molecules

E. The acetylcholine channel is always open, and never switchesto a closed conformation

6. After opening briefly along the axon of a neuron,voltage-gated ion channels switch to an inactivated conformationthat slowly returns to the original closed conformation of theprotein. This slow change in conformation, requiring about amillisecond, is important because

A. all of the ions that were transported across the membranewhen the ion channels were open must be actively transported backto the other side of the membrane, restoring the originalconcentration gradient, before the ion channels can open again

B. ATP hydrolysis is necessary to drive this energeticallyunfavorable change in conformation

C. it prevents the action potential from reversing direction andtraveling back toward the cell body of the neuron

D. the channel protein must be dephosphorylated in order tocomplete the transport process and return to the originalnonphosphorylated conformation

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BIO130H1 Chapter Notes - Chapter quiz7: Potassium Channel, Osmosis, Partition Coefficient

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