BIOL1006 Lecture Notes - Lecture 16: Protein Folding, Active Transport, Adenosine Triphosphate

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carminedeer281

9 Aug 2016

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All substances that move through the membrane do so by one of two general methods, which are categorized based on whether or not energy is required. Passive transport is the movement of substances across the membrane without the expenditure of cellular energy. During this type of transport, materials move by simple diffusion or by facilitated diffusion through the membrane, down their concentration gradient. Water passes through the membrane in a diffusion process called osmosis. Osmosis is the diffusion of water through a semi- permeable membrane down its concentration gradient. It occurs when there is an imbalance of solutes outside of a cell versus inside the cell. The solution that has the higher concentration of solutes is said to be hypertonic and the solution that has the lower concentration of solutes is said to be hypotonic. Water molecules will diffuse out of the hypotonic solution and into the hypertonic solution.

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

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

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

BIOL1006 Lecture Notes - Lecture 16: Protein Folding, Active Transport, Adenosine Triphosphate

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