Assimilation: Definition, Function, Diagram and Examples

What Is Assimilation?

Assimilation is the intake of food by living organisms and its conversion into vital forces. In biology, it is the most vital process by which nutrients being absorbed are transformed into a utilizable form in an organism. Assimilation helps in the growth and repair processes, along with being the source of energy for all living beings. This is an anabolic process because it builds bigger from smaller molecules. Hence, essential for survival of all living organisms.

Importance of Assimilation

Assimilation is important because:

• Supplies energy for life processes

• Enables growth and repair of tissues

• Helps synthesis of enzymes and hormones

• Maintains metabolism and cellular activities

Assimilation In Plants

Plants introduce nutrients as a consequence of assimilation, for example by photosynthesis and nitrogen assimilation.

Photosynthesis and Carbohydrate Assimilation

Photosynthesis is the series of acts by which plants transform, in the collaboration of sunlight energy, carbon dioxide and water to glucose and oxygen, so glucose obtained by the plants is a source of energy as well as a basic material from which all other requisites will be built.

Nitrogen Assimilation

Plants absorb nitrogen from the soil, generally in the form of nitrates or ammonium salts. They synthesize this into amino acids and proteins, which plants need in large quantities for their growth and development.

Role of Cell Organelles

Photosynthesis occurs specifically in the chloroplasts. Other organelles, such as vacuoles and mitochondria also play roles in storing and utilizing the produced nutrients.

Assimilation in Animals

Nutrient absorption follows the completion of digestion and assimilation. Communication Assimilation and nutrient uptake follow the mode of nutrition.

Digestive System and Nutrient Absorption

The ingested nutrient is broken down by the animal's digestive system into simpler and smaller molecules, after which the walls of the intestines absorb those small molecules into the blood.

Conversion into Biological Macromolecules

Once the nutrients are assimilated, some are absorbed in the blood and transported to the appropriate cells in the form of specific amino acids, fatty acids, and glucose, which, upon formation, become identified proteins, lipids, and glycogen, respectively.

Assimilated Nutrients and Their Uses

The assimilated nutrients yield proteins that are synthesized for repairing muscles and tissue, fats for storage as long-term energy sources, and carbohydrates for use as an immediate energy source.

Examples Of Assimilated Nutrients

Proteins are formed for the repairing of muscles and tissue, fats are stored as long-term energy sources, and carbohydrates are ingested to provide immediate energy.

Assimilation In Humans

Assimilation is a process where, in humans, this work is collectively done by different organs and forms a groundwork of complex biochemical pathways.

Nutrient Assimilation Pathway

The ingestion of the food, its digestion, and the absorption of the absorbed molecules occur in the gastrointestinal tract. The molecules are then transferred into the blood by absorption and infuse into the liver and other constituent tissues to convert them into useful forms.

Role of Liver and Other Organs

Dietary nutrition metabolism, glycogen storage, and detoxification of harmful materials become central functions of the liver. Other organs, such as the pancreas and kidneys, equally play their part in regulating and using up the nutrients.

Cellular Level Assimilation

This is respiration at the cellular level — conversion of nutrients into energy and building of cellular constituents.

Role Of Mitocondia

The energy corpuscles responsible for converting the nutrients needed are the mitochondria, which break down the replete nutrients available into adenosine triphosphate, ATP, which is the actual form of energy in a cell.

Cellular Pathways of Assimilation

The cellular respiration process includes glycolysis, the Krebs cycle, and oxidative phosphorylation. All these take place at the cellular level and are the main processes for assimilation and use of the digested nutrients.

Need and Functions of Assimilation

Absorption becomes relevant for a number of the following vital functions associated with the biological life processes:

Production Of Energy

Energy for all cellular activities and all organismal functions comes from assimilated nutrients by the process of absorption.

Tissue Growth And Repair

Nutrients are to be used for synthesizing proteins and several other molecules necessary to enable tissue growth and repair.

Synthesis Of Required Biomolecules

Assimilation brings with it synthesis—enzymes, hormones, and all such required biomolecules.

Examples and Applications of Assimilation

Assimilation takes place in plant and animal kingdoms as well and sometimes finds practical applications.

Plant and Animal Examples

For example, in the case of plant nitrogen assimilation, it occurs in plant growth and development. In the case of animals, it is used for protein synthesis. Then, farmers grow such organisms for food using even more nitrogen-based fertilizers.

Practical Applications

Understanding assimilation can help enhance proper quantity usage in applications, such as farming and further medical innovations regarding disorders that are caused by nutritional deficiencies.

Assimilation NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Assimilation in Plants and Animals

• Need and function of assimilation

Practice Questions for NEET

Q1. Absorbed substances finally reach the tissues which utilise them for their activities , this process is called

1. Assimilation

2. Absorption

3. Digestion

4. Mastication

Correct answer: 1) Assimilation

Explanation:

Assimilation is the process by which absorbed nutrients are delivered to the cells and tissues that need them for various functions. After digestion and absorption, nutrients such as glucose, amino acids, and fatty acids are transported through the bloodstream to different cells throughout the body. This process takes place at the cellular level in organs like the liver, muscles, adipose tissue, and other target cells.

Hence, the correct answer is option 1) Assimilation.

Q2. Which of the following statements is incorrect?

1. Faecal accumulation in the rectum initiates a neural reflex causing an urge for its removal.

2. Irregular bowel movements cause constipation.

3. In diarrhea absorption of food is increased.

4. All of the these

Correct answer: 3) In diarrhea absorption of food is increased.

Explanation:

The digestive wastes, solidified into coherent faeces in the rectum initiate a neural reflex causing an urge or desire for its removal. The egestion of faeces to the outside through the anal opening is called defecation. It is a voluntary process and is carried out by a mass peristaltic movement

Hence, the correct answer is option 3) In diarrhoea absorption of food is increased.

Q3. Removal of digestive wastes, solidified into coherent feces in the rectum initiates a neural reflex causing an urge or desire for its removal the process is known as:

1. Ingestion

2. Defaecation

3. Egestion

4. Assimilation

Correct answer: 2) Defaecation

Explanation:

The above process is termed the defecation reflex. Thus, when the rectum is filled with fecal matter, it activates the stretch receptors and sends information to the brain, initiating an urge to move it out. It is also, therefore, a process consisting of both involuntary and voluntary actions within the muscles that expel waste from the body.

Hence, the correct answer is option 2) Defaecation.

Also Read:

• MCQs on Assimilation and Egestion

• Digestive Glands

• Alimentary Canal

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