What are Nutrients?
A nutrient is a substance that an organism requires in order to survive, grow, and reproduce. Animals, fungi, plants, as well as protists, must all consume dietary nutrients. Nutrients can be incorporated into cells for metabolic purposes, or they can be metabolised by cells to form non-cellular formations such as hair, scales, feathers, or exoskeletons.
Some nutrients, like carbohydrates, lipids, proteins, and fermented products (ethanol or vinegar), can be metabolically transformed into smaller molecules in the process of releasing energy, resulting in end-products of water and carbon dioxide. Water is required by all organisms. Energy sources, some of the amino acids which are combined to form proteins, a subset of fatty acids, vitamin supplements, and certain minerals are all essential nutrients for animals.
Plants require a broader range of minerals absorbed through their roots, as well as carbon dioxide and oxygen absorbed through their leaves. Fungi feed on dead or living organic matter to meet their host's nutrient requirements.
Organic Nutrients
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Organic nutrients are the foundations for various cell components that some organisms cannot synthesise and must therefore obtain preformed. Carbohydrates, protein, and lipids are examples of these compounds. Other organic nutrients involve vitamins, which are needed in small amounts due to either their catalytic or regulatory contribution in metabolism.
Inorganic Nutrients
A variety of inorganic elements (minerals) are required for the development of living things. Boron, for example, has been shown to be necessary for the growth of many—possibly all—higher plants but has not been indicted as an essential component in the nutrition of microbes or animals. Fluorine traces (as fluoride) are unquestionably beneficial, if not essential, for proper tooth formation in higher animals.
Similarly, animals require iodine (as iodide) for the formation of thyroxine, the active form of an important regulatory hormone. Silicon (as silicate) is an important component of the outer skeletons of diatomaceous protozoans and other organisms, and it is required for normal growth. The need for silicon is much lower in higher animals.
Calcium is a less obvious example of a specialised mineral requirement; it is required in relatively large amounts by higher animals because it is a major component of bone and eggshells (in birds); calcium is an essential nutrient but only as a trace element for other organisms. Mineral elements of various types are present in trace amounts in almost all foods. It can't be assumed that non-essential mineral elements don't play a role in metabolism.
Carbohydrates
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Let’s know what carbohydrates are! Carbohydrates synthesised by plants are the most important nutrients in terms of quantity, as they provide the majority of the energy used by the animal kingdom. Sugars in mature fruit attract birds and other small animals. The seed coats in the fruit survive their rapid passage through the guts of these animals, scattering the plant's still viable seeds widely. Sucrose accumulates in the stems of sugarcane and the roots of sugar beet, acting as an energy reserve for each plant; both are used in the industrial production of table sugar.
Organic vs Inorganic Nutrients
The distinction is in "how" and "when" the plants absorb these nutrients. Using inorganic nutrients is akin to inserting an IV line into your plants' veins. Those nutrients are immediately available and are absorbed by the plant regardless of whether it requires or desires them at the time. Inorganic nutrients bypass the growing medium and reach the plant directly.
Organic nutrients follow nature's slower processes. Once in the soil, organic nutrients require/take time to degrade. Organic nutrients require the assistance of microbe life to break down organic material and make nutrients available. Once available, the plant will consume the nutrients as needed.
Organic nutrients feed the soil, which in turn feeds the plant. Inorganic nutrients are directly absorbed by the plant. There is a significant difference.
Inorganic Micronutrients
Vitamins and minerals, in general, are referred to as micronutrients. Macronutrients include proteins, fats, and carbohydrates.
In comparison to macronutrients, your body requires fewer micronutrients. That is why they are referred to as "micro." Humans must obtain micronutrients from food because, for the most part, your body cannot produce vitamins and minerals. That is why they are also known as essential nutrients.
Vitamins are organic compounds produced by plants and animals that are degraded by heat, acid, or air. Minerals, on the other hand, are inorganic and can only be found in soil or water. When you eat, you consume the vitamins produced by plants and animals, as well as the minerals they absorb.
Because the micronutrient content of each food varies, it is best to eat a variety of foods to ensure adequate vitamin and mineral intake. A sufficient intake of all micronutrients is required for optimal health, as each vitamin and mineral serves a specific function in your body.
Vitamins and minerals are essential for growth, immune function, brain development, and a variety of other processes. Certain micronutrients, depending on their function, also play a role in disease prevention and treatment.
FAQs on Inorganic Nutrients
1. What are inorganic nutrients and why are they essential for living organisms?
Inorganic nutrients are chemical elements or compounds that originate from non-living sources, such as soil, water, and air. Unlike organic nutrients (like carbohydrates and proteins), they do not contain carbon-hydrogen bonds. They are crucial for life as they serve as structural components of cells, regulate metabolic processes, and maintain osmotic balance. For example, calcium is vital for bone structure in animals, while magnesium is a central component of chlorophyll in plants.
2. What is the main difference between organic and inorganic nutrients in terms of how they are used by plants?
The primary difference lies in their availability and absorption. Inorganic nutrients are mineral ions (e.g., nitrate, phosphate) present in the soil and are immediately available for uptake by plant roots. Organic nutrients, on the other hand, are complex compounds in organic matter (like humus) that must first be broken down by soil microbes into inorganic forms before plants can absorb them. Essentially, inorganic nutrients feed the plant directly, while organic nutrients feed the soil first.
3. Can you provide key examples of inorganic nutrients required by plants?
Yes, inorganic nutrients for plants are categorised based on the quantity required.
- Macronutrients (required in large amounts): These include Carbon, Hydrogen, Oxygen, Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), and Sulphur (S).
- Micronutrients (required in small amounts): These include Iron (Fe), Manganese (Mn), Copper (Cu), Molybdenum (Mo), Zinc (Zn), Boron (B), Chlorine (Cl), and Nickel (Ni).
4. How do plants absorb inorganic nutrients from the soil?
Plants absorb inorganic nutrients, primarily as mineral ions dissolved in soil water, through their roots. This absorption occurs via two main pathways. Some minerals enter the root cells through diffusion (passive transport), moving from a higher concentration in the soil to a lower concentration in the root. However, most minerals are taken up through active transport, a process that requires energy (ATP) to move ions against their concentration gradient, ensuring the plant gets the necessary amount of each nutrient.
5. Are vitamins and minerals considered organic or inorganic?
This is a key distinction. Vitamins are organic compounds because they are complex carbon-based molecules made by plants and animals. For example, Vitamin C is ascorbic acid. Minerals, on the other hand, are inorganic elements that originate from the earth (soil and water) and are absorbed by plants or consumed by animals. Examples include iron, calcium, and potassium.
6. Why are some inorganic nutrients classified as macronutrients while others are micronutrients?
The classification is not based on the nutrient's importance, as all are essential, but purely on the quantity required by the plant for healthy growth. Macronutrients are needed in relatively large amounts (generally >10 mmole kg⁻¹ of dry matter) because they form the main structural and functional components of the plant, such as proteins, nucleic acids, and chlorophyll. Micronutrients, or trace elements, are needed in very small amounts (generally <10 mmole kg⁻¹ of dry matter) as they primarily function as co-factors for enzymes in metabolic reactions.
7. What happens if a plant receives an excess of an inorganic nutrient? Can it be toxic?
Yes, an excess of any inorganic nutrient can be harmful. The requirement for micronutrients is very specific; a moderate increase above the optimal concentration can lead to toxicity. For example, an excess of manganese can induce deficiencies of other nutrients like iron, magnesium, and calcium by competing with them for uptake and binding sites. Toxicity symptoms can include the appearance of brown spots surrounded by chlorotic (yellowing) veins.
8. How does the availability of inorganic nutrients in soil impact an entire ecosystem?
The availability of inorganic nutrients, particularly nitrogen and phosphorus, acts as a fundamental control on an ecosystem's productivity. In natural ecosystems, these nutrients are often limiting factors, meaning their scarcity restricts plant growth, which in turn limits the populations of herbivores and carnivores. Conversely, an excess of these nutrients, often from agricultural runoff, can cause eutrophication in aquatic ecosystems, leading to algal blooms that deplete oxygen and harm fish populations.
9. Why is nitrogen, despite being 78% of the atmosphere, often a limiting inorganic nutrient for plants?
This is because plants cannot use atmospheric nitrogen (N₂) directly. The strong triple bond between the two nitrogen atoms makes the molecule very inert. For plants to absorb it, N₂ must be converted into usable inorganic forms like ammonia (NH₃) or nitrate (NO₃⁻). This conversion process, called nitrogen fixation, is primarily carried out by specialised soil bacteria. Since this biological process is slow and limited, the availability of fixed nitrogen in the soil often restricts plant growth, making it a critical limiting nutrient.
