The digestive activity is regulated by mechanical and chemical receptors found in the walls of the tract organs.
To enhance absorption effectiveness in the small intestine, the surface area of the mucosal lining is increased by structures like plicae circulares and intestinal villi .
DNA replication is conducted by the polymerase II enzyme within eukaryotic cells. This enzyme incorporates nucleotides that are complementary to the leading strand and then to an RNA strand that starts the replication process.
When the 3' _ >5' exonuclease detects a mismatched pair of bases, it cuts and removes those bases. The polymerase II then fits the correct base pair and continues the replication process.
Every cell is encased in a protective layer referred to as the cell membrane. In plants, an additional barrier known as the cell wall offers further protection. All organelles found within cells are enclosed structures.
Cell membranes consist of a phospholipid bilayer featuring both extrinsic and intrinsic proteins. Studies of the plasma membrane structure revealed that the protein patterns of MITOCHONDRIA and CHLOROPLAST are most akin to that of the cell membrane.
