BIOL 2160 Lecture Notes - Lecture 6: Electrochemical Gradient, Passive Transport, Cell Membrane

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1 Oct 2016

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Passive transport: transport across the membrane does not require energy. Active transport: transport across the membrane requires energy. Molecules move across membranes from high energy to low energy. Energy of a solution depends on solute concentration. Therefore, solutes move passively from areas of high concentration to areas of low concentration. How can ion concentrations vary in intracellular vs. extracellular solutions: charged molecules can"t cross without help of other proteins no simple diffusion, so ion concentrations don"t eventually even out. Force pushes from higher to lower energy. Molecules are subject to three types of driving force: chemical, electrical, electrochemical. The chemical force for potassium is always out. Chemical gradiant wants to drive sodium in; always. Amount of electrical driving force depends on membrane potential. Membrane potential is a difference in electrical potential or voltage across the plasma membrane. Determined by the combination of the chemical driving force and the electrical driving force.

Related Questions

1 Which of the following statements is false?

(a) CO₂ and O₂ can diffuse freely across the cell membranes.

(b) The differences in permeability between artificial lipid bilayers and cell membranes arise from variations in phospholipid content.

(d) Cells expend energy in the form of ATP hydrolysis to maintain ion concentrations that differ from those found outside the cell.

2 Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell. Which of the following ions is the most abundant inside a typical mammalian cell?

(a) Na⁺

(b) K⁺

(d) Cl^â

3 Pumps are transporters that are able to harness energy provided by other components in the cells and drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called _____________.

(a) active transport.

(b) free diffusion.

(d) passive transport.

harlequinbuffalo618

Match each term

1.facilitated diffusion 2. Hypertonic solution
3. Hypotonic solution
4. Active Transport
5. Secondary acive transport
6. Simple Diffusion

A.	The transport of a nonpolar molar across a biological membrane from the compartment with a high concentration to one with low concentration.
B.	A process that utilizes energy to move compounds against a concentration gradient, i.e., from the compartment with lower concentration to one with a higher concentration.
C.	a solution that would cause blood cells to swell and burst
D.	a solution that would cause red blood cells to shrink
E.	The transport of a hydrophilic molecule across a biological membrane using an ion gradient created by an electrogenic pump.
F.	A process by which compounds are transported from a region of high concentration to one of lower concentration using membrane proteins as transporters.

1,Match the descriptions to the type of transport.

- A. B. C.	Water enters a cell because it is hypertonic compared to the extracellular environment, increasing its turgor pressure
- A. B. C.	Water enters guard cells because the guard cells are hypertonic compared to the surrounding cells
- A. B. C.	Potassium ions are pumped into guard cells
- A. B. C.	The motor cells of a Venus fly trap are hypotonic compared to surrounding cells, causing water to leave the motor cells
- A. B. C.	Sugar is loaded into the phloem

A.	Both active and passive transport
B.	Passive Transport
C.	Active transport

2,Describe what is wrong with the following statement and explain why:

All prokaryotic and eukaryotic cells contain plasma membrane, nucleus, ribosomes, organelles, cytoplasm, and cell walls.

What is short-distance transport?

	a,	The movement of solutes from a region of low concentration to a region of high concentration
		b,The movement of water, nutrients, and other substances between cells
c,		The movement of substances from a region of high concentration to a region of low concentration
d,		The movement of water across a semipermeable membrane from a region of low solute concentration to a region of high solute concentration.

What terms describe the movement of water across a semipermeable membrane from a region of high water concentration towards a region of low water concentration (and high solute concentration.)

What is found in the proptoplasm?

Cell wall, cytoplasm, plasma membrane, nucleus, and other cell organelles

Plasmodesmata, cell wall, and plasma membrane

Cell wall, cytoplasm, and plasma membrane

Cytoplasm, nucleus, and other cell organelles

The channels that allow nutrients and protoplasm to pass between plant cells are called _________________.

What happens when a plant cell is placed in a hypotonic solution?

Water will enter the plant cell and the plasma membrane will swell and cell lysis will occur

Water will leave the plant cell and the plasma membrane will pull away from the cell and plasmolysis will occur

Water will enter the plant cell and the plasma membrane will swell and push against the cell wall

Water will leave the plant cell and the plant cell will lose turgor pressure, causing the plant to wilt

________________ transport uses cellular energy.

What molecules make plasma cell membranes hydrophilic on the outside and hydrophobic on the inside?

What type of cells do plants have?

		Bacterial
		Archaeic
		Eukaryotic
		Prokaryotic

BIOL 2160 Lecture Notes - Lecture 6: Electrochemical Gradient, Passive Transport, Cell Membrane

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