CELL201 Lecture Notes - Lecture 6: Mechanosensitive Channels, Facilitated Diffusion, Water Potential

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skycaribou653

1 Feb 2018

School

University of Alberta

Department

Cell Biology

Course

CELL201

Professor

Paul Lapointe

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Document Summary

Cell shrinks: hypotonic solution: less than concentration. Cell bursts: solute molecule decreases the free energy of the solution, so water moves from low to high. Isotonic solution: equal concentration solute concentration to maximise free energy of the solution. Ion channels: selective, lined with hydrophilic atoms, selectivity based on amino acid side chains and a size filter. Most ion channels are gated to prevent reaching equilibrium as disequilibrium is what drives the channel. Ligand- gated channel where a substance binds to the protein to open the gate. In nervous systems, voltage-gated, dissimilarity of positive and negative charges across the membrane. Mechanosensitive channels: mechanical force on channel opens gate, common in skin, emergency cell protective mechanism eg. water rushing in hypotonic solution, cell membrane stretches, mechanical force on the channels. Atp regulates the opening and closing of ion channel cftr. Many types of mutations can cause cystic fibrosis.

Related Questions

Read the following scenarios and indicate which of the following processes they describe.

11. Sodium molecules move randomly around a solution of sodium chloride in water, frequently colliding with other sodium ions and chloride ions. secondary active transport diffusion osmosis facilitated diffusion primary active transport

12. Sodium ions (Na+) move through sodium channels in a synthetic membrane. primary active transport secondary active transport facilitated diffusion osmosis

13. Water molecules move into the cytosol of a cell placed in a hypotonic solution. primary active transport secondary active transport facilitated diffusion osmosis

14. Water molecules move into the cytosol of a cell placed in pure water. facilitated diffusion osmosis secondary active transport primary active transport

15. Water molecules move out of a cell placed in a hypertonic solution. facilitated diffusion primary active transport secondary active transport osmosis

16. The action of sodium-potassium pumps moves sodium ions (Na+) out of a cell and potassium ions (K+) into a cell. facilitated diffusion secondary active transport osmosis primary active transport

17. Glucose molecules move into cells lining the intestine against their concentration gradient driven by the movement of sodium ions (Na+) into the cells down their concentration gradient. osmosis secondary active transport primary active transport facilitated diffusion

18. A beaker of water is separated by a selectively permeable membrane that allows the passage of water but not ions. A solution of 4% sodium chloride (NaCl) is placed on one side of the membrane and pure water is placed on the other side of the membrane. The solutions are allowed to equilibrate. At this point, which process is going on? facilitated diffusion osmosis secondary active transport primary active transport

amaranthelk944

1. predict the direction of water movement based on differences in solute concentrations. Use the terms osmotic pressure, hypotonic, isotonic, and hypertonic
2. Why do membranes have to be selectively permeable?

3. What determines whether a particular substance can diffuse (simple or facilitated) through a membrane?

4. What mechanisms drive molecules across membranes? Use the terms concentration gradient, (facilitated) diffusion and active transport.
5. Which parts of the plasma membrane proteins do you expect to be hydrophobic or hydrophilic? Justify your answer.
concise and short answers pls

A hypertonic solution has a higher level of solutes so the water moves out of the cells to the surroundings

A hypotonic solution has a higher level of solutes so the water moves out of the cells to the surroundings

The salt and water solution in the potato is a hypotonic solution

Osmosis is the movement of large molecules across a membrane which require embedded proteins

The plain water in this experiment is the solvent and the salt is the solute.

Passive transport requires no energy and the molecules move with the concentration gradient or from high concentration to low concentration

Active transport required no energy and the molecules move with the concentration gradient or from high concentration to low concentration.

The water on the inside of the potato with the salt molecules is an isotonic solution the same as the solution on the outside of the potato.

Water will not move by simple diffusion (osmosis) into or out of cells it requires energy or protein transporters

The solution of salt water in the potato has a lower concentration of water molecules so the water on the outside should move into the cells

CELL201 Lecture Notes - Lecture 6: Mechanosensitive Channels, Facilitated Diffusion, Water Potential

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