With regard to the semipermeable nature of the plasma membrane,which of the following would readily cross without the aid of a transport protein?
A)calcium ions
B)glucose
C)water
D)amino acids
E)DNA

Question

Quizplus · Accepted Answer

Water molecules are small and uncharged, making them able to freely diffuse across the plasma membrane without the aid of a transport protein. Calcium ions and amino acids are both charged and relatively large, making them unable to freely diffuse across the membrane. Glucose also cannot freely diffuse across the membrane due to its size and polarity. DNA is a large molecule that is unable to pass through the plasma membrane at all.

With Regard to the Semipermeable Nature of the Plasma Membrane,which