Question

question 1 (2.5 points)
what accounts for the fluidity that defines the fluid mosaic model of a typical plasma membrane?
the proteins, being large, cause the membrane to jiggle around
the phospholipids collectively form a jelly - like substance similar to the cytoplasm
the phospholipids are not bonded to each other and thus are freer to move around
water molecules infiltrate the bilayer causing it to become more watery and thus more fluid
the phospholipids in a typical plasma membrane form covalent bonds which are elastic and allow the membrane to stretch
question 2 (2.5 points)
hydrophobic interactions of phospholipid tails make the____conformation of cell membranes possible
lipid bilayer

Explanation:

• For Question 1: In the fluid mosaic model, phospholipids in the plasma membrane are not covalently bonded to each other. This lack of bonding allows them to move around more freely, which is the basis of membrane fluidity. Proteins do not cause the membrane to "jiggle" in the way described. Phospholipids do not form a jelly - like substance similar to cytoplasm. Water molecules do not infiltrate the bilayer in a way that causes this fluidity. And phospholipids do not form covalent bonds that allow stretching in the relevant sense for fluidity.
• For Question 2: Phospholipids have hydrophilic heads and hydrophobic tails. The hydrophobic interactions of the tails cause them to aggregate together, away from water, while the hydrophilic heads face outward (towards water). This results in the formation of a lipid bilayer.

Answer:

Question 1: The phospholipids are not bonded to each other and thus are freer to move around.
Question 2: lipid bilayer.