Thin, flexible barrier around a cell; regulates what enters and leaves the cell
- contains the cytoplasm (all interior cell organelles and the cytosol) - allowing the chemical reactions in the cell to occur
<span>- semipermeable (or selectively permeable) - allows certain substances in, keeps others out </span>
<span>- offers limited protection</span>
<span>vestigial structures because they are hard </span>
Movement of cell against concentration gradient is called a.osmosis