Some antibiotics act as carriers that bind an ion on one side of a membrane, diffuse through the membrane, and release the ion on the other side. The conductance of a lipid-bilayer membrane containing a carrier antibiotic decreased abruptly when the temperature was lowered from 40°C to 36° C. In contrast, there was little change in conductance of the same bilayer membrane when it contained a channel-forming antibiotic. Why?

A cell creates a H+ gradient across a membrane- in other words, a situation is created were the concentration of H+ is higher on one side then the other of a membrane. How can this H+ concentration gradient be used to do work (that the cells needs to do)?

Isotonic saline and 5% dextrose in water are solutions considered isotonic to human blood. What effect on red blood cells would you expect if a patient were given these fluids intravenously? A solution of 10% dextrose in water is hypertonic to human blood.

Paramecium caudatum lives in a hypotonic solution. Excess water is removed from the cell via structures called contractile vacuoles. Given what you know about vacuoles (refer to Table 3.3, p. 68) and what you know about cells able to contract, suggest the type of transport that occurs when water is moved out of Paramecium.

Compare and contrast the following methods of a passing cell membrane in terms of movement with respect to the concentration gradient, use of ATP, and the use of transporters with examples. (Simple) diffusion vs Facilitated diffusion

What could happen to the proteins of cells treated with high amounts of free radicals that would effect the diffusion of those treated cells?

What is the role of lysozyme and a low ionic strength extraction buffer? Select all that apply. Cells absorb water from a low ionic strength extraction buffer, by osmosis, swell and lyse, releasing their contents Lysozyme breaks down bonds in the cellulose cell wall of plants, weakening the structure Cells release water into a low ionic strength extraction buffer by osmosis, shrink and lyse, releasing their contents Lysozyme is an enzyme found in lysosomes in cells Lysozyme breaks down bonds in the peptidoglycan cell wall of bacteria, weakening the structure Lysozyme is an antibiotic found in tears, saliva, human milk and mucus.

The image below depicts 3 membrane carrier proteins. Describe the different types of membrane carrier proteins (1, 2 and 3) in terms of their direction of transportation. A 1. A B 2 A 3 B

Statement 1: The direction of diffusion of a solute across a membrane is determined by its concentration gradient and always moves toward equilibrium. Statement 2: In passive transport, solutes move down the gradient from a region of low concentration to a region of high concentration. A Both statements are true. Both statements are false. C) Statement 1 is true. Statement 2 is false. Statement 1 is false. Statement 2 is true.

4) Two membrane preparations have been made from the plasma membrane of erythrocytes (i.e red blood cells) and are being maintained in an isotonic buffer solution: (1) right-side-out membrane vesicles, in which the exoplasmic leaflet of the vesicle faces the buffer (equivalent in orientation to that of the exoplasmic leaflet of the intact plasma membrane); and (2) inside-out membrane vesicles in which the exoplasmic leaflet faces the interior of the vesicles and the cytoplasmic leaflet faces the buffer. 80 a. Right-side-out vesicles (ROVS) Very Low Fluorescence Inside-out vesicles (IOVS) Very High Fluorescence A newly discovered phosphoglyceride, called phosphotidylalanine is currently being studied. Annexin V is a protein that binds to phosphatidylalanine, which is one of the phospholipids present in the cell membrane preparations described above. Fluorescently labeled Annexin V is mixed with each vesicle preparation. The vesicles are washed to remove unbound Annexin V and then…