If you're a fat molecule forming the inner layer of a cell membrane, your head will face toward?

Question

A. the watery environment outside the cell

B. the watery envirnment inside the cell

C. either the inside or the outside of the cell

D. the protein pump in the cell

Answer 1

B.

The inner layer faces inwards, the outer layer faces outwards...with the 'tails' facing each other.

Answer 2

B

The cell membrane consist of 2 layers of phospholipids. The heads of the phosphplipids (the phosphate ends) are polar and are pointed either towards the inside or the outside of the cell because it is hydrophilic (water-loving) and wants to be in touch with the watery environment inside the cell (cytoplasm) or the intracellular fluid. The other end of the phospholipid molecule (the fatty tail) is hydrophobic (water-fearing) and does not like to be in contact with cytoplasm or intracellular fluid.

Think of phospholipids as lollipops with the candy part as the head of the molecule (phosphate end) and the handles as the tails (the lipid end). Now point the handles towards each other and form a circle. You will see that the candy ends of the lollipops point withe towards the inside or the outside of the circle.

So if you are a phospholipid molecule forming the inner layer of a cell membrane, your head will face towards the watery environment inside the cell (cytoplasm).

Answer 3

B.  The head of a phospholipid (the fat molecules that make up cell membranes) is the phosphate group.  The phosphate group is polar, so it likes an equally polar environment - the watery cytoplasm.  Because this molecule is a part of the INNER layer of the membrane, the answer is B.