Modes of Nutrition in Living Organisms

Nutrition is the relationship between health, diet, and disease. We intake food for growth and development and receive energy in the form of nutritive food. This intake of nutrients that helps us to sustain and grow is called nutrition. This is the nutrition definition Biology can relate with. Broadly explained, it involves Science where the study of nutrients and other food substances are studied to gain knowledge about the maintenance, growth, health, reproduction, and disease of an organism. It also includes all processes taking place in the body like absorption, assimilation, food intake, catabolism, biosynthesis, and excretion. Healthy nutrition is important for the body with the right and balanced nutrients present in the diet we consume. It will prevent diseases from occurring and maintain the right kind of lifestyle. Unhealthy nutrition is harmful physically as well as mentally, therefore, one should always seek the correct food in the right proportions and a variety of food that helps us heal all the time. A nutritionist gives a healthy nutrition plan and helps you maintain the right weight and calories goal. Knowing all of these, by now, you must have been aware of what nutrition is all about.

Not only human beings, but all living organisms including plants and microorganisms require nutrition to survive healthily. Therefore, nutrition in living organisms is equally important for all to obtain energy and derive nutrients for growth and development. There are various types of nutrition that an organism can engage in and we will know each of them further.  

The Six Basic Nutrients To Not Skip

1. Water

Water makes up 45-75% of the human body and is essential for us. Water is needed to be used in different processes of the body and helps to control our temperature.

2. Carbohydrates (carbs for short)

Carbs are the major source of energy for the human body. In our bodies, blood sugar is the firewood that runs cells in our bodies. Carbohydrates can be very easily digested in the form of sugar and can also be complex and difficult to digest in the form of starch or fiber. We in reality can’t absorb fiber, but it plays a significant role in gut wellbeing and managing cholesterol metabolism.

3. Protein

Protein is made up of amino acids that act as the building blocks for our tissues. Protein in our diet is made use of for the growth, repair, and repair of tissue in our body. Protein can also be converted into blood glucose to be used as energy if we aren't already getting enough energy from carbohydrates.

4. Fat

Fat is one of the most concentrated sources of energy, that provides double the quantity of calories per gram. Fat is a way of storing extra calories by our bodies for use later on. Despite this less advantageous function, fats are important for our body in so many ways, too. Fat is used in the process of digestion acting as one to the hormones, shielding the human body, and providing absorption of a shock to guard diverse parts of our body like in the soles of our feet, in our palms, and also around other internal organs.

5. Vitamins

Although they are needed in much smaller quantities than the nutrients mentioned above, vitamins are important for your body to work on a daily basis. Each and every vitamin works as part of a diverse course in your body, helping in making your metabolism better over time, growth, and also the development of the immune system (among many other functions) to work properly. 

6. Minerals

Minerals are elements that you must have seen in the periodic table in chemistry that is also necessary for our bodies to be in motion. Some of the minerals are made use of for metabolic processes and others are used by the human body as part of the body structures, just as the calcium present in our bones and also teeth. Like vitamins, diverse foods hold many different kinds of minerals. 

These were the six major nutrients – water, protein, carbohydrates, vitamins, fat, and minerals. Each of them plays an important and unique role in how the human body functions. 

Modes of Nutrition

The different modes of nutrition can answer the following question:

How Do Organisms Obtain Their Nutrition?

The below diagrammatic representation shows the different modes of nutrition in a precise manner which we will also describe ahead.

Depending upon the various modes of nutrition in living organisms, nutrition can be divided into the following categories:

• Autotrophic Nutrition

• Heterotrophic Nutrition

Autotrophic Nutrition

Nutrition in living organisms varies according to their way of food consumption. Autotrophic nutrition refers to that kind of nutrition when organisms are involved in making their own food. They can be classified into: 

• Photoautotrophs- Organisms that make their own food by using sunlight as the source of energy are called photoautotrophs. Eg: Green plants, algae, and photosynthetic bacteria.

• Chemoautotrophs- Organisms that synthesize food with the oxidation of chemicals. Eg: Sulphur-oxidizing bacteria, cyanobacteria, and iron-oxidizing bacteria.

Certain Characteristics of These Kinds of Organisms Include:

• They synthesize their own organic molecules from simple inorganic substances like carbon dioxide and water.

• Organisms that synthesize their own organic molecules are referred to as producers. So, autotrophs are often termed as producers.

• For example, plants synthesize their own food via photosynthesis in the presence of sunlight. During this process, the oxidation of inorganic compounds takes place to generate oxygen and energy in the form of glucose (sugar or carbohydrates). The biochemical reaction involved in photosynthesis is written as-

            6CO2 + 6H2O → C6H12O6 + 6O2

• The photosynthetic process includes three stages namely absorption, conversion, and reduction. 

• During absorption, the chlorophyll pigment present in the plant leaves traps the sunlight.

• During conversion, chemical energy is generated from the absorbed light  and water gets converted to hydrogen and oxygen molecules.

• During reduction, hydrogen molecules combine with the carbon and reduce carbon dioxide to carbohydrates or sugar molecules. 

• Plants or autotrophic organisms like algae, cyanobacteria, seaweed and phytoplankton depend on other micro and macro elements present in their environment to synthesize their own food. Green plants depend on soil to get various nutrients too which are used to produce proteins and other essential organic compounds. 

Some examples of autotrophs are Phytoplankton, Algae, Seaweed, Grass, Wheat, a Maize plant, blue-green algae bacteria, and Cyanobacteria, and much more.

Things to Keep in Mind when it comes to Autotrophs!

• Autotrophic nutrition is taken in by autotrophs, i.e. organisms who are masters at making their own food.

• There are two ways by which autotrophs make their nutrition: Chemosynthesis and photosynthesis.

• In photosynthesis, food is made from sunlight. Green plants indulge in the process of photosynthesis

• The reaction of the process of photosynthesis is termed as 6CO2 + 6H2O → C6H12O6 + 6O2

• In the process of chemosynthesis, chemicals are used in place of light in order to make food.

Heterotrophic Nutrition

Heterotrophic nutrition is one of the types of nutrition when organisms are unable to synthesize their own food and depend upon other organisms for deriving the nutrients. 

Certain Characteristics Of These Organisms Include-

• These organisms obtain organic molecules or food from other organisms that can be living or recently killed or non-living remains and detritus.

• Heterotrophs cannot produce their own organic molecules and therefore depend upon other sources of energy, thus they are termed as consumers. 

• If you ask what is the mode of nutrition in human beings? Then here is the answer to the question. Examples of heterotrophs include human beings who depend upon plants and animals to derive their food.

• Other examples include all herbivorous, carnivorous, and omnivorous animals like tigers, leopards, lions, snakes, dogs, cats, fungi, parasites, etc.

Heterotrophs Can Be Further Classified Into The Following:

• Consumers where they ingest organic molecules from living or recently killed organisms. This category includes examples like parasitic leeches, ticks, humans, deers, lions, etc.

• Heterotrophs who ingest organic molecules through non-living remnants of various organisms are detritivores. Examples include hummus and detritus.

• Saprotrophs live on dead and decaying organic matter by releasing digestive enzymes to absorb the nutrients. These are often termed as decomposers. Examples include mycorrhizal fungi, orchids, mushrooms and molds.