Answer:
What is Active Transport?
In cellular biology, active transport is the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: primary active transport that uses adenosine triphosphate (ATP), and secondary active transport that uses an electrochemical gradient.
Some examples of active transport include:
- Phagocytosis of bacteria by macrophages,
- Movement of calcium ions out of cardiac muscle cells,
- Transportation of amino acids across the intestinal lining in the human gut,
- Secretion of proteins such as enzymes, peptide hormones, and antibodies from various cells,
- Functioning of white blood cells to defend invading diseases.
In short, active transport is the process of moving molecules across a cellular membrane through the use of cellular energy.
What is a cell membrane ( plasma membrane )?
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment.
Have a wonderful day! :-)