GENERAL HISTOLOGY

INTRODUCTION

CELL STRUCTURE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What does “selectively permeable” mean?
A
Only certain things are allowed in and out
B
It’s only flexible in certain environments
C
Only pairs with certain cells
D
Only completes certain tasks
Explanation: 

Detailed explanation-1: -A selectively-permeable membrane is a membrane that allows only some substances and molecules to pass into or leave the cell. An example of a selectively-permeable membrane is the cell membrane. It allows the passage of only certain types of molecules through diffusion and occasionally by facilitated diffusion.

Detailed explanation-2: -The cell membrane is selectively permeable, meaning it only lets certain things in and out of the cell.

Detailed explanation-3: -The membrane is selectively permeable because substances do not cross it indiscriminately. Some molecules, such as hydrocarbons and oxygen can cross the membrane. Many large molecules (such as glucose and other sugars) cannot. Water can pass through between the lipids. Ions such as H+ or Na+ cannot.

Detailed explanation-4: -Selective permeability of the cell membrane refers to its ability to differentiate between different types of molecules, only allowing some molecules through while blocking others. Some of this selective property stems from the intrinsic diffusion rates for different molecules across a membrane.

Detailed explanation-5: -They are semi-permeable, which means that some molecules can diffuse across the lipid bilayer but others cannot. Small hydrophobic molecules and gases like oxygen and carbon dioxide cross membranes rapidly. Small polar molecules, such as water and ethanol, can also pass through membranes, but they do so more slowly.

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