Question

Define plasma membrane and passive transport.

Answer 1

Plasma Membrane  regulates the movement of materials between the ordered interior of the cell and the outer environment.
 passive transport is movement of materials across cell membranes without using energy.

Answer 2

Plasma Membrane or Cell Membrane is a membrane which encloses the cytoplasm which further contains various cell organelles and Nucleus. Nucleus + Cytoplasm = Protoplasm. Plasma Membrane is a semi - permeable or selectively permeable membrane. It is very specific in nature and allows only selective material sin and out of the cell. It is a living membrane. It is present both in plant cells and animal cells. It is made up of a double layer of lipids and proteins in present in it.

Passive transport is the movement of ions and other atomic or molecular substances across the Cell membrane or Plasma membranes. It does not require an input of cellular energy because it is  driven by the tendency of the system to grow in an entropy.