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Assimilation is the process of converting a nutrient into a usable form (e.g., liquid or solid) that is absorbed into the tissues and organs after digestion or chemical change of chemicals in the circulation by the liver or cellular secretions.
It refers to the processes of photosynthesis and raw material absorption that plants use to get their nourishment. Photosynthesis, nitrogen fixation, and food absorption after digestion into living tissue are all examples of assimilation.
What is Assimilation?
In biology, assimilation is defined as the process by which living organisms incorporate nutrients from a variety of external sources into their bodies and use them to meet the energy needs necessary to stay alive.
Assimilation, in another sense, refers to the absorption of vitamins, minerals, and other substances from food in the intestine.
Assimilation can also refer to the breaking down of complex chemicals found in meals into smaller particles, and then the transportation of those smaller units to places in the live body where they are needed, such as active cells.
Some of the practical applications of biological assimilation include photosynthesis, nitrogen fixation, magnesium supplement conversion, and the formulation of biological tissues and fluids via nutrient adsorption into the human body after digestion in the intestine.
Assimilation also aids in the growth, regeneration, structural development, and reproduction of organisms, as well as the replenishment of energy stores in the body. The human body is described as an open system in thermodynamics, which implies that it can only live and thrive with the continuous intake of energy from external resources, which supports the importance of assimilation in biology.
Impact of Assimilation in Living Organisms
Solar irradiation is the universe’s principal source of energy for all living things. The earth’s living creatures are classified into two categories depending on their utilisation of various forms of nourishment to meet their energy demands:
1. Autotrophic Organisms (Autotrophic Organisms)
2. Organisms that are heterotopic
Autotrophic organisms are those that can produce their own food using just light, water, carbon dioxide, and other substances. Carbon fixation, also known as carbon assimilation, is the process by which inorganic molecules in the form of different carbon oxides are transformed into organic compounds such as carbohydrates, amino acids, proteins, and other important components.
Based on their use of sunlight and inorganic oxidation processes, autotrophic organisms are further categorised as photoautotrophs and litho autotrophs. Heterotopic organisms, on the other hand, are species that are incapable of creating their own food and rely exclusively on receiving energy from external sources by absorbing the organic matter found in the food they consume.
As a result, complex proteins and carbohydrates are transformed into glucose and amino acids during absorption. As a result, glucose is used in respiration while amino acids are obtained for the creation of new proteins. It’s crucial to understand that dissimilation (the regeneration of component components as a result of destruction) and assimilation are continual processes.
Assimilation is a highly important process for the transportation of digested food particles into various cells of the body where energy is required, as can be seen from the previous explanation.
Assimilation is a process that happens to almost all living creatures on the planet. See the list below for some instances of assimilation in diverse species.
Nitrogen is a necessary component for plant life and development. The nitrogen is provided to the plants by a variety of fertilisers or by the soil absorbing nitrogen from the atmosphere. The process of assimilation in plants begins when microorganisms in the soil convert nitrogen to ammonium, which is subsequently turned back into nitrates, which are easily absorbed by the roots of the plants.
After the absorption cycle, amino acids, nucleic acids, and chlorophyll are all formed around the nitrates that have been absorbed. Furthermore, the assimilation process is used in the above-mentioned carbon fixation process in autotrophic organisms.
Invertebrates’ eating and digesting are two of the most critical processes in their absorption. Although absorption is a simple process in certain invertebrates, it is a time-consuming one in others. Tapworms take nutrients directly from the digestive tract of the host. Through a process known as phagocytosis, sponges and corals immediately absorb food particles.
In nematodes, there is a single, lengthy digestive system that runs from mouth to anus. As a result, it may be inferred that all invertebrates obtain energy from nutrients in some fashion, and they all use absorbed nutrients for development and energy.
Human Digestion: Assimilation
In order to absorb food and water, humans have a more sophisticated digestive system than plants and insects. Food that is injected into the mouth travels all the way to the stomach, where digestion begins. Hydrochloric acid kills the pathogenic bacteria, and the bigger food particles are digested into smaller ones that are carried into cells.
The meal is pushed into the small intestine after passing through the stomach, where it is combined with liver bile and pancreatic secretions. The meal is correctly digested, and the nutrients are then sent to various cells in the body where energy is necessary.
The leftover mesh is sent to the big intestine once the nutrients have been distributed. As a result, it may be inferred that the small intestine is the site of assimilation in human bodies.
Assimilation of Nutrients
The food we consume is absorbed by our body’s cells. The procedure involves breaking down food into smaller particles, digesting it, and then distributing it to various regions of our body. Furthermore, as previously stated, absorption transports nutrients from meals to cells, where they are needed for growth and reproduction.
It is critical to comprehend the notion of nutrient absorption by going through the meal digestive cycle. The mouth is where food is chewed, thus the digestive system begins there. The saliva generated by the salivary glands moistens the meal, allowing it to travel down the oesophagus and into the stomach. Saliva also breaks down the starches into smaller bits.
Very powerful acids and enzymes break down the meal as it enters the stomach, separating it into distinct components such as carbs, proteins, and fatty acids. As a result, food digestion is only half completed before being pushed into the small intestine, where nutrients are absorbed.
Following partial digestion of food in the stomach, a mixture of food, liquids, and digestive fluids is moved in a very regulated and controlled manner via the small intestine, often known as the bowl. The tiny intestine connects the stomach to the large intestine and is a tightly folded tube.
The small intestine is in charge of much of the digestion and is primarily in charge of nutrient absorption and assimilation in the meal.The typical length of the small intestine in adults is around 7 metres.
The small intestine is further split into three segments: duodenum, jejunum, and ileum, all of which are covered by the omentum anteriorly. Each region of the gut has a specific role in nutrition absorption. The food initially enters the duodenum, where it is combined with different secretions such as bicarbonate, digestive enzymes, and bile salts, which help to speed up the digesting process.
The duodenum is split into four sections: inferior, superior, ascending, and descending, each measuring around 25 cm in length. Bile salts from the liver are frequently used to breakdown fats found in the diet. Pancreatic enzymes aid in the digestion of carbohydrates and lipids.
Bicarbonate from the pancreas neutralizes the stomach acid that enters with the meal. The optimal functioning of the liver and pancreas is linked to efficient food digestion and conversion into nutrients. After appropriate digestion in the duodenum, the chyme is transported to the jejunum, where about 90% of nutritional absorption, including protein, carbs, vitamins, and minerals, occurs.
Microvilli are tiny projections found throughout the small intestine. They’re utilised to boost nutrition absorption by intestinal cells. The digested nutrients are then released into the circulation, allowing other cells to be fed as well. Finally, the ileum completes the absorption of water, bile salts, and certain surplus vitamins, after which the additional food particles are transported into the large intestine or colon.
Malabsorption and Assimilation
The small intestine’s primary function in the digestive process is to absorb nutrients from food and transport them to the cells via the circulation. The smooth operation of the bowl might be caused by a number of different disorders. As a result, these illnesses are known as malabsorption syndromes.
The gut is unable to absorb and digest both micronutrients (minerals and vitamins) and macronutrients (proteins and fats) in malabsorption diseases (fats, carbohydrates, and proteins). Malabsorption syndrome is caused by intestinal damage, excessive medication usage, lactose insufficiency, peracetic illnesses, radiation therapy, and a damaged intestine lining.
Doctors think that faeces, blood, breath, imaging tests, and biopsies can all be used to forecast the illness. In addition, the malabsorption problem can be addressed with a change in diet, vitamin and enzyme supplements, and avoiding dairy products. Malabsorption syndrome is thought to have a negative impact on nutritional absorption in the human body.
Factors Affecting Assimilation
The absorption of nutrients is influenced by a variety of variables. Temperature, the content of the food intake, the time gap between two meals, the age of the culture, and changes in cell concentration and structure are some of the major elements that doctors have identified as affecting the absorption of organic matter.
The researchers, on the other hand, think that the human body reacts differently in the absorption process depending on the type of food consumed. Furthermore, everyday use of green tea and occasional fasting has been shown in many study papers to strengthen the digestive system, resulting in a more advanced absorption process.
Summary of Assimilation
The distribution of nutrients to diverse cells is required for their development, health, and reproduction, as shown in the preceding section. Assimilation is the process by which nutrients are transported from the small intestine to their final destinations. It is thought that the aforementioned mechanism occurs in both autotrophic and heterotrophic species.
Furthermore, the duodenum is responsible for full digestion in the small intestine, whereas the jejunum is responsible for 90% of nutritional absorption, including protein, carbs, vitamins, and minerals. The ileum then completes the absorption of water, bile salts, and certain extra vitamins.
Various variables, including the quantity and content of the food consumed, the time interval between meals, the age of the culture, and changes in cell concentration and structure, are thought to influence the assimilation process.
Malabsorption syndromes, a problem that develops when the small intestine malfunctions owing to injury in the gut, excessive use of medications, lactose insufficiency, peracetic illnesses, radiation therapy, and a damaged intestinal lining, further complicate the smooth execution of assimilation.
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- Plant nitrogen uptake and assimilation: regulation of cellular pH homeostasis. J Exp Bot . 2020 Jul 25;71(15):4380-4392.
- Assimilation of alternative sulfur sources in fungi. World J Microbiol Biotechnol . 2018 Mar 17;34(4):51.