Question

Explain the characteristics of plasma membranence and discuss different types of membrane transport.(word limits 500)

Answer 1

Answer:

The plasma membrane protects the cell from its external environment, mediates cellular transport, and transmits cellular signals.

The plasma membrane (also known as the cell membrane or cytoplasmic membrane) is a biological membrane that separates the interior of a cell from its outside environment.

The primary function of the plasma membrane is to protect the cell from its surroundings. Composed of a phospholipid bilayer with embedded proteins, the plasma membrane is selectively permeable to ions and organic molecules and regulates the movement of substances in and out of cells. Plasma membranes must be very flexible in order to allow certain cells, such as red blood cells and white blood cells, to change shape as they pass through narrow capillaries.

The plasma membrane also plays a role in anchoring the cytoskeleton to provide shape to the cell, and in attaching to the extracellular matrix and other cells to help group cells together to form tissues. The membrane also maintains the cell potential.

In short, if the cell is represented by a castle, the plasma membrane is the wall that provides structure for the buildings inside the wall, regulates which people leave and enter the castle, and conveys messages to and from neighboring castles. Just as a hole in the wall can be a disaster for the castle, a rupture in the plasma membrane causes the cell to lyse and die.

Explanation:

The cell employs a number of transport mechanisms that involve biological membranes:

1.Passive osmosis and diffusion: transports gases (such as O2 and CO2) and other small molecules and ions

2.Transmembrane protein channels and transporters: transports small organic molecules such as sugars or amino acids

3.Endocytosis: transports large molecules (or even whole cells) by engulfing them

4.Exocytosis: removes or secretes substances such as hormones or enzymes