Question

a) Which of the following is/are TRUE regarding Osmolarity and Tonicity?

     a. A Hyperosmotic solution is always Hypertonic
     b. A Isosmotic solution may be Isotonic or Hypertonic but not Hypotonic
     c. A Hyposmotic solution may be Hypotonic, Isotonic or Hypertonic
     d. All of the above are true
     e. None of the above is true

b) Which of the following is NOT a second messenger molecule used in cellular signal transduction pathways?

     a. cyclic GMP
     b. Inositol triphosphate
     c. Phospholipase A2
     d. Diacylglycerol
     e. cyclic AMP

c) Which of the following is/are true regarding facilitated diffusion? (2 points)

     a. It is an active process requiring ATP
     b. It uses a protein carrier in the cell membrane
     c. It utilizes a concentration gradient of one molecule to move another molecule against its concentration gradient
   d. All of the above are true

d) A patient comes into the hospital with very low blood pressure. Which solution below will expand his plasma volume to the greatest extent and remain in the plasma. Which of the following solutions is the best choice? (4 points)

        a. Hypertonic Saline (NaCl solution)
        b. Hypertonic Albumin (protein solution)
        c. Hypotonic Dextrose (d-glucose solution)
        d. Hypotonic Potassium Chloride (KCl solution)

Answer 1

Ans-a. e. None of the above is true

A hyperosmotic solution is not always hypertonic. It can be hypertonic, hypotonic or isotonic as well. But a hyposmotic solution is always hypotonic. Also,isosmotic solution can be hypertonic, hypotonic or isotonic. Example of a solution which is isosmotic and hypotonic is plant cells do not have sucrose transporters, so an isosmotic sucrose solution will be hypotonic to the plant cell.

Ans-b. c. Phospholipase A2

SecindaSe messengers are small molecules and ions that relay signals from the cells to the effector proteins. There are various secondary messengers involved in cell signalling like calcium ions, cyclic AMP, cyclic GMP, inositol triphosphate, diacycdiacylgyl, etc.

Ans-c. b. It uses a protein carrier in the cell membrane

Facilitated diffusion is a type of tramspotr mechanism in which molecules are passed across the cell membrane along the concentration gradient without the use of energy. The substances move in the presence of carrier or channel proteins which crosses specific substances across the membrane.

Ans-d. a. Hypertonic saline ( NaCl solution)

When the person is in hyotension, the sodium levels are increased by infusion of saline. A normal saline is given which will replace the blood volume and normalise the blood pressure. However, here hypertonic saline is given to expand his plasma volume and increase the blood pressure.