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Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.

The Nitrogen Cycle

JoVE 10934

Nitrogen atoms, present in all proteins and DNA, are recycled between abiotic and biotic components of the ecosystem. However, the primary form of nitrogen on Earth is nitrogen gas, which cannot be used by most animals and plants. Thus, nitrogen gas must first be converted into a usable form by nitrogen-fixing bacteria before it can be cycled through other living organisms. The use of nitrogen-containing fertilizers and animal waste products in human agriculture has greatly influenced the natural nitrogen cycle. About 78% of the air we breathe is nitrogen gas. However, in this form, N2, few organisms are able to use it. Nitrogen makes up essential molecules in all organisms, like proteins and DNA. Unable to use the atmospheric form of nitrogen, most organisms use the byproducts of nitrogen-fixing and nitrifying prokaryotes. Nitrogen fixation converts nitrogen gas (N2) into ammonia (NH3), whereas nitrification converts NH3 into nitrites (NO2-) and nitrates (NO3-). Plants can directly use the ammonia and nitrates, and plant-eating organisms obtain nitrogen by ingesting plants. When these organisms die, bacteria in the soil are able to convert the organic nitrogen into ammonia in a process called ammonification. Through denitrification, aerobic bacteria can then convert a

 Core: Biology

Stoichiometry, Product Yield, and Limiting Reactants- Concept

JoVE 11141

Chemical equations represent how a chemical reaction proceeds from reactants to products through physical or chemical change using chemical formulas.


Stoichiometry is a term that describes the relative quantities of reactants and products in a chemical reaction. It is based on the Law of Conservation of Mass, which is a fundamental law that states that matter is neither created…

 Lab: Chemistry

Carbon and Nitrogen Analysis of Environmental Samples

JoVE 10012

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University


Elemental Analysis is a method used to determine elemental composition of a material. In environmental samples such as soils, scientists are particularly interested in the amounts of two ecologically important elements, nitrogen and carbon. Elemental analysis by …

 Environmental Science

Soil Nutrient Analysis: Nitrogen, Phosphorus, and Potassium

JoVE 10077

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University


In this experiment, three soil macronutrients are chemically extracted, combined with color-based reagents, then analyzed using color to determine the nutrient concentration present in the soil sample.


Nitrogen, phosphorus, and…

 Environmental Science

What are Nucleic Acids?

JoVE 10684

Nucleic acids are long chains of nucleotides linked together by phosphodiester bonds. There are two types of nucleic acids: deoxyribonucleic acid, or DNA, and ribonucleic acid, or RNA. Nucleotides in both DNA and RNA are made up of a sugar, a nitrogen base, and a phosphate molecule.

A cell’s hereditary material is comprised of nucleic acids, which enable living organisms to pass on genetic information from one generation to next. There are two types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA and RNA differ very slightly in their chemical composition, yet play entirely different biological roles. Chemically, nucleic acids are polynucleotides—chains of nucleotides. A nucleotide is composed of three components: a pentose sugar, a nitrogen base, and a phosphate group. The sugar and the base together form a nucleoside. Hence, a nucleotide is sometimes referred to as a nucleoside monophosphate. Each of the three components of a nucleotide plays a key role in the overall assembly of nucleic acids. As the name suggests, a pentose sugar has five carbon atoms, which are labeled 1o, 2o, 3o, 4o, and 5o. The pentose sugar in RNA is ribose, meaning the 2o carbon carries a hydroxyl group. The sugar in DNA is deoxyribose, meaning the 2o

 Core: Biology

Transforming, Genome Editing and Phenotyping the Nitrogen-fixing Tropical Cannabaceae Tree Parasponia andersonii

1Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University & Research, 2Center of Technology for Agricultural Production, Agency for the Assessment and Application of Technology (BPPT), 3Department of Ecological Science, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, 4Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture

JoVE 59971

 Genetics

The Roles of Bacteria and Fungi in Plant Nutrition

JoVE 11104

Plants have the impressive ability to create their own food through photosynthesis. However, plants often require assistance from organisms in the soil to acquire the nutrients they need to function correctly. Both bacteria and fungi have evolved symbiotic relationships with plants that help the species to thrive in a wide variety of environments.

The collective bacteria residing in and around plant roots are termed the rhizosphere. These soil-dwelling bacterial species are incredibly diverse. Though some may be pathogenic, most have roles in promoting plant health. In exchange, the bacteria receive nutrition from plants in the form of carbohydrates, amino acids, and nucleic acids. The bacteria called rhizobacteria can protect plants by producing antibiotics or absorbing toxic metals in the soil. Additionally, bacteria help plants by accessing otherwise unusable stores of nutrients in the soil. For example, plants lack the molecular machinery to utilize nitrogen from the atmosphere directly. Instead, they take up nitrogen in the form of ammonium (NH4+) and nitrate (NO3- ), which is generated by soil-residing bacteria. During a process called nitrogen fixation, soil-dwelling bacteria convert atmospheric nitrogen to ammonia. Nitrogen-fixation requires large amounts of ATP that bacteria derive from plant-provided carbohydrates. Other groups of bacter

 Core: Biology

Key Elements for Plant Nutrition

JoVE 11103

Like all living organisms, plants require organic and inorganic nutrients to survive, reproduce, grow and maintain homeostasis. To identify nutrients that are essential for plant functioning, researchers have leveraged a technique called hydroponics. In hydroponic culture systems, plants are grown—without soil—in water-based solutions containing nutrients. At least 17 nutrients have been identified as essential elements required by plants. Plants acquire these elements from the atmosphere, the soil in which they are rooted, and water. Nine of these essential nutrients—collectively called macronutrients—are needed by plants in more significant amounts. The macronutrients include carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur, calcium, magnesium, and potassium. Critical plant compounds, such as water, proteins, nucleic acids, and carbohydrates, contain macronutrients. Macronutrients also regulate cellular processes. For example, potassium regulates the opening and closing of stomata for gas exchange. Plants need micronutrients in smaller amounts. These include chlorine, iron, manganese, boron, zinc, copper, nickel, and molybdenum. Many micronutrients function as cofactors, which enable the activity of enzymes. Therefore, without micronutrients, plants are unable to perform critical functions. A plant experiencing an

 Core: Biology
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