Question

1. What is the osmotic concentration of a solution containing 300 mM NaCl and 100 mM glucose? Is it iso-, hypo-, or hyper- osmolar?

	A.	700 mOsm/L, hyper-osmolar
	B.	600 Osm/L, iso-osmolar
	C.	200 Osm/L, hypo-osmolar
	D.	400 mOsm/L, hyper-osmolar

2. Ocean water has a high salt concentration compared to body fluids. If you were adrift at sea drinking seawater will not help you, and may make you even more dehydrated! What explains this?

	A.	Water diffuses from body tissues into the intestines because of the higher osmolarity of seawater.
	B.	Waste contaminants in seawater clog pores in intestinal epithelial cells, thereby blocking water absorption.
	C.	Water is actively pumped by the intestinal epithelial cells into the body from the intestine. This requires enormous amounts of ATP (active transport) and the waste products are osmolytes.
	D.	Seawater is hypertonic and that makes cells swell.

3.   What you predict the concentration of Na+, K+, and Ca2+ in a T cell to be?

A.130 mM Na+, 3.5 mM K+, and 2.4 mM Ca2+

B.4 mM Na+, 70 mM K+, and 0.4 µM Ca2+

C. 140 mM, 5.2 mM, and 0.2 mM

D. 9.5 mM Na+, 140 mM K+, and 0.1 µM Ca2+

Answer 1

1st question-

Osmolarity of a solution is the sum of concentration of solutes present in it.

In the solution, the sodium chloride dissociate to form sodium ions and chloride ions. Thus 300 mM of sodium chlorine will form 300mM of sodium ion and 300mM of chloride ion.

Total osmolarity= 300+300+100(glucose)

= 700mOml/litre

And the solution will be hyperoemolar because there is high concentration of solutes in the solution which will make it hyperosmolar and water will move into this solution ir placed alongside isotonic solution.

2nd question-

option 1st is correct.

Explanation- sea water contains high concentration of salts in it which makes it hyperosmolar. When this water enters our body, due to hyperosmolarity , the water which is present inside our cells will move out and will shrink. This will result in dehydration.

3rd question-

The concentration of sodium ions is highest in T cell. It followed by potassium ion and lastly calcium ion. So according to this,option 3 is correct.