The digestive system prepares nutrients for utilization by body cells through six activities, or functions.
Ingestion
The first activity of the digestive system is to take in food through the mouth. This process, called ingestion, has to take place before anything else can happen.
Mechanical digestion
The large pieces of food that are ingested have to be broken into smaller particles that can be acted upon by various enzymes. This is mechanical digestion, which begins in the mouth with chewing or mastication and continues with churning and mixing actions in the stomach.
Chemical digestion
The complex molecules of carbohydrates, proteins, and fats are transformed by chemical digestion into smaller molecules that can be absorbed and utilized by the cells. Chemical digestion, through a process called hydrolysis, uses water and digestive enzymes to break down the complex molecules. Digestive enzymes speed up the hydrolysis process, which is otherwise very slow.
Movements
After ingestion and mastication, the food particles move from the mouth into the pharynx, then into the esophagus. This movement is deglutition, or swallowing. Mixing movements occur in the stomach as a result of smooth muscle contraction. These repetitive contractions usually occur in small segments of the GI tract and mix the food particles with enzymes and other fluids. The movements that propel the food particles through the GI tract are called peristalsis. These are rhythmic waves of contractions that move the food particles through the various regions in which mechanical and chemical digestion takes place.
Absorption
The simple molecules that result from chemical digestion pass through cell membranes of the lining in the small intestine into the blood or lymph capillaries. This process is called absorption.
Elimination
The food molecules that cannot be digested or absorbed need to be eliminated from the body. The removal of indigestible wastes through the anus, in the form of feces, is defecation or elimination.
Hydrolysis
The process of breaking larger molecules into smaller molecules is called catabolism. This process typically involves the release of energy as larger molecules are broken down into smaller units that can be used for cellular activities.
Endocytosis is the process that allows cells to take in molecules of solids by surrounding them with the cell membrane to form a vesicle. This process encompasses phagocytosis for larger particles and pinocytosis for smaller substances.
Yes, a dehydration reaction joins smaller molecules by removing a water molecule. This process results in the formation of larger molecules and the release of a molecule of water as a byproduct.
The process you are referring to is called catabolism. Catabolism involves breaking down large molecules into smaller ones, releasing energy in the process. This process is essential for producing energy and building blocks for anabolic reactions in cells.
Digestion.
Hydrolysis
Digestion is a chemical process that breaks down food particles into smaller molecules through the action of enzymes. It involves the breakdown of complex molecules into simpler ones through chemical reactions.
The process of breaking larger molecules into smaller molecules is called catabolism. This process typically involves the release of energy as larger molecules are broken down into smaller units that can be used for cellular activities.
Yes, synthesis is the process of creating more complex compounds from simpler substances. It involves combining elements or smaller molecules to form larger, more complex molecules through chemical reactions.
The process of breaking down complex food molecules into simpler food molecules is called digestion. It begins in the mouth with the mechanical and chemical breakdown of food, continues in the stomach where more chemical digestion occurs, and is completed in the small intestine where nutrients are absorbed into the bloodstream. Enzymes play a key role in this process by breaking down larger molecules into smaller ones that the body can use for energy and growth.
Enzymes break down smaller molecules quicker because they have active sites that specifically fit the smaller molecules, allowing for faster and more efficient reactions. Additionally, smaller molecules have less complex structures which make them easier for enzymes to process and catalyze.
You question makes no sense. If particles dissolve they go into solution, they do not "break apart and scatter".
True. Anabolism is the process in which smaller molecules are combined to form larger, more complex molecules. This process requires energy and is important for the growth and repair of tissues in living organisms.
No, a solution has much smaller particles than a colloid. In a solution the particles are individual atoms, molecules, or ions.
They are complex molecules made from smaller molecules.
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