In the cell membrane, the hydrophilic part of the phospholipid molecule: Group of answer choices a.faces the exterior of the cell. b.faces the interior of the cell. c. is in the center of the phospholipid bilayer. d. both A and B.

Why can't ions like sodium (Na+) or potassium (K+) diffuse directly through the phospholipid bilayer?   A. Ions can only use active transport to move through the membrane B. Ions are hydrophobic and are repelled by the polar membrane C. Ions are polar and are repelled by the nonpolar part of the membrane D. Ions need to become stable before entering the cell

What type of energy helps drive the passive processes of diffusion, osmosis, and facilitated diffusion? (Pick ALL correct statements involved with this.) In other words what are all the TRUE statements regarding these processes? Select one or more: a.random motion which increases when temperature increases b.ATP energy c.random motion which increases when molecules have large molecular weight d.random motion which increases when molecules concentration decreases e.random motion which increases when molecules concentration increases f.random motion which decreases when temperature decreases g.random motion which increases when molecules have low molecular weight

Consider the following diagram of the cell membrane. Which of the statements is NOT true regarding the cell membrane?   Group of answer choices a. Proteins and carbohydrates are also components of the cell membrane. b. Certain phospholipids and proteins on the outer surface of the cell membrane are attached to carbohydrates. c. Some carbohydrates extend through the entire lipid bilayer and appear on both surfaces of the membrane d. Some of the proteins embedded in the cell membrane constitute channels (passage canals).

For biological membranes, which of the following statement is NOT true? A. The phospholipid bilayer is a fluid matrix. B. Protein can be anchored to the membrane by covalently linked lipid chains. C. Proteins can move laterally across the membrane. D. For organisms living in cold temperature, their cell membranes contain more triacylglycerols. E. Transverse motion of lipid molecules can occur occasionally.   Enzyme lowers when... A. The energy difference between the substrate and the transition state B. The energy difference between the product and the transition state C. Both A and B D. Neither A nor B

Which of the following compounds can diffuse through the lipid bilayer of a cell membrane? Select all that apply.     A. Large polar molecules   B. Gases and hydrophobic molecules   C. Ions   D. Small polar molecules like water

Which of the following is incorrect about the collagen structure? a. The covalent cross-links between the individual chains stabilize the collagen structure b. None; all the other choices are correct The helical structure is cross-linked (with covalent bonds) at both ends Od. Gly residues are all located in the center of the helix (i.e. between the individual chains) C.

The lipid bilayer has membrane proteins spanning the membrane. They have a hydrophobic region embedded in the _______________ while the hydrophilic regions are on the ______________ and _______________ of the cell.

3) For each case given below, describe how the fluidity of membranes will change (increase or decrease) and why this change will happen. A. Increasing the number of double bonds (unsaturation) of the fatty acids in the phospholipids. B. Increasing the length of the fatty acid chains. C. Increasing the cholesterol content of the membrane D. Increasing temperature