Question

question 21

the cell membrane is ___, which means that it allows some substances to pass through while blocking others.

• closed barrier
• impermeable
• openly permeable
• selectively permeable

question 22

the model of the plasma membrane emphasizes the structure and function of how many layers of phospholipids?

• 3
• 2
• 5
• 4

Explanation:

Analyze Question 21

Using the Cell Membrane Function knowledge point

The cell membrane regulates what enters and leaves the cell. A barrier that allows only certain substances to pass through while blocking others is defined as selectively permeable (or semipermeable). Therefore, the correct option is "selectively permeable".

Analyze Question 22

The plasma membrane is structurally composed of a double layer of lipid molecules. This double layer is known as a phospholipid bilayer, which consists of exactly 2 layers of phospholipids. Therefore, the correct option is "2".

Answer:

Question 21

• closed barrier
• impermeable
• openly permeable
• selectively permeable (Correct answer)

Question 22

• 3
• 2 (Correct answer)
• 5
• 4