Question

IMPORTANT!!
The cell membrane is selectively permeable. O2 diffuses across the phospholipid bilayer. K+ must cross the cell membrane using a membrane protein. Which property of the cell membrane prevents the diffusion of K+?

A) The membrane proteins are attracted to the charged ions.

B) Only very small particles are able to diffuse across the cell membrane.

C) The lipid tails are hydrophobic, repelling charged ions such as K+.

D) The phosphate heads are hydrophobic and prevent the passage of polar substances.

Answer 1

Answer:

The answer is C. The lipid tails are hydrophobic, repelling charged ions such as K+.

Answer 2

Answer:

Option C is correct

Explanation:

The phospholipids layer of plasma membranes consists of both water attracting and fearing regions due to which some elements easily pass through this membrane while some face obstruction. All charged molecules (such as metal ions) and polar molecules like water are not allowed through the lipid tail. Water interacts with the hydrophilic head effectively but does face issues in passing through the hydrophobic head region. Also all metal ions like potassium, calcium, sodium etc. and non-metallic ions such as chlorine cannot pass through the membrane.  

Hence, option C  is correct