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In bacteria, the Tat system exports proteins from the cytoplasm across the inner cell membrane; whereas in chloroplasts, it is present in the thylakoid membrane where it aids the import of proteins from the stroma. [13] Tat proteins are highly variable in different bacteria and are classified into three major types, namely TatA, TatB, and TatC.
The restriction modification system (RM system) is found in bacteria and archaea, and provides a defense against foreign DNA, such as that borne by bacteriophages.. Bacteria have restriction enzymes, also called restriction endonucleases, which cleave double-stranded DNA at specific points into fragments, which are then degraded further by other endonucleases.
The bacterial flagellum is made of about 20 proteins, with approximately another 30 proteins required for its regulation and assembly. [152] The flagellum is a rotating structure driven by a reversible motor at the base that uses the electrochemical gradient across the membrane for power.
The lactose operon (lac operon) is an operon required for the transport and metabolism of lactose in E. coli and many other enteric bacteria.Although glucose is the preferred carbon source for most enteric bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available through the activity of β-galactosidase. [1]
The seven major classes of nutrients are carbohydrates, fats, fiber, minerals, proteins, vitamins, and water. [7] Nutrients can be grouped as either macronutrients or micronutrients (needed in small quantities). Carbohydrates, fats, and proteins are macronutrients, and provide energy. [7]
Proteases occur in all organisms, from prokaryotes to eukaryotes to viruses. These enzymes are involved in a multitude of physiological reactions from simple digestion of food proteins to highly regulated cascades (e.g., the blood-clotting cascade, the complement system, apoptosis pathways, and the invertebrate prophenoloxidase-activating cascade).
Protein degradation is a major regulatory mechanism of gene expression [1] and contributes substantially to shaping mammalian proteomes. [2] Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called proteases, but may also occur by intra-molecular ...
Digestive enzymes take part in the chemical process of digestion, which follows the mechanical process of digestion. Food consists of macromolecules of proteins, carbohydrates, and fats that need to be broken down chemically by digestive enzymes in the mouth, stomach, pancreas, and duodenum, before being able to be absorbed into the bloodstream ...