BIO E105 Lecture Notes - Lecture 7: Chalcogen, Facilitated Diffusion, Passive Transport

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rubyporpoise450

16 Dec 2020

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Active transport by pumps: cells can transport molecules or ions against an electrochemical gradient. This process requires energy in the form of atp and is called active transport: pumps are membrane proteins that provide active transport of molecules across the membrane. For example, the sodium-potassium pump, na+/k+-atpase, uses atp to transport na+ and. A sodium ion is smaller than a potassium ion. To further complicate the matter, hydrated ions have different shell sizes. A hydrated na+ ion is actually larger than a hydrated k+ ion. Specificity is determined by spacing of cation binding sites. Carbonyl oxygen group of residues thr 75, val 76, gly 77 and tyr 78 are shown in red. The spacing of the selectivity filter is such that four carbonyl oxygen atoms can replace the electrostatic interactions of water molecules around k+ ions. But the spacing is inappropriate to displace water from na+ ions.

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 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.

BIO E105 Lecture Notes - Lecture 7: Chalcogen, Facilitated Diffusion, Passive Transport

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