What structures make the plasma membrane hydrophobic?
The hydrophobic, or “water-fearing,” part of a phospholipid consists of its long, nonpolar fatty acid tails. The fatty acid tails can easily interact with other nonpolar molecules, but they interact poorly with water.
Are plasma membranes hydrophobic?
The plasma membrane is composed of a bilayer of phospholipids, with their hydrophobic, fatty acid tails in contact with each other.
What causes the plasma membrane to function as a hydrophobic barrier?
Two general features of phospholipid bilayers are critical to membrane function. Because the interior of the phospholipid bilayer is occupied by hydrophobic fatty acid chains, the membrane is impermeable to water-soluble molecules, including ions and most biological molecules.
Is the core of the plasma membrane hydrophobic or hydrophilic?
In contrast, the interior of the cell membrane is hydrophobic and will not interact with water. Therefore, phospholipids form an excellent two-layer cell membrane that separates fluid within the cell from the fluid outside of the cell.
What part of the plasma membrane is hydrophobic quizlet?
The portion of the bilayer that is hydrophobic is the phospholipid of the cell membrane tails.
What is the hydrophobic portion of a phospholipid called?
Phospholipids consist of a glycerol molecule, two fatty acids, and a phosphate group that is modified by an alcohol. The phosphate group is the negatively-charged polar head, which is hydrophilic. The fatty acid chains are the uncharged, nonpolar tails, which are hydrophobic.
What is the permeability of the plasma membrane?
Permeability of cell membrane refers to the ease with which a molecule can pass through a cell membrane. It is the rate at which the passive diffusion occurs through the membrane. Transporting molecules across the cell membrane is one of the important functions of the cell membrane.
How do hydrophobic molecules move across a membrane?
3 – Simple Diffusion Across the Cell (Plasma) Membrane: The structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion.
What molecules are hydrophobic and can easily cross the plasma membrane quizlet?
Small, nonpolar molecules are hydrophobic, so they can easily cross the phospholipid bilayer of the plasma membrane. Polar molecules and ions are hydrophilic, so they cannot very easily cross the hydrophobic portion of the plasma membrane (formed by the phospholipid tails).
Which portion of the phospholipid is hydrophobic?
What are three elements that float in the plasma membrane?
The principal components of a plasma membrane are lipids (phospholipids and cholesterol), proteins, and carbohydrates attached to some of the lipids and some of the proteins. A phospholipid is a molecule consisting of glycerol, two fatty acids, and a phosphate-linked head group.