Related Experiment Video
Updated: May 28, 2026
09:00
Live Cell Imaging of Early Autophagy Events: Omegasomes and Beyond
Published on: July 27, 2013
What is an autotroph?
Vijayasarathy Srinivasan1, Harold J Morowitz, Harald Huber
1Krasnow Institute for Advanced Study MS 2A1, George Mason University, Fairfax, VA 22030, USA. vsriniva@gmu.edu
Archives of Microbiology
|October 1, 2011
Summary
Autotrophy relies on a single carbon source for growth. This study proposes a refined definition for true autotrophs in biochemical research, clarifying the role of secondary compounds in growth media.
Area of Science:
- Biochemistry
- Microbiology
- Cell Biology
Background:
- Autotrophy is defined by the use of a single carbon source for anabolism in pure cultures.
- The addition of secondary carbon compounds, such as chelators or vitamins, complicates the precise definition of autotrophy.
- Existing definitions may not adequately address the complexities encountered in contemporary biochemical studies.
Purpose of the Study:
- To clarify the definition of autotrophy for pure cultures.
- To distinguish between primary carbon sources and auxiliary compounds in growth media.
- To provide a definition suitable for modern biochemical research on autotrophs.
Main Methods:
- Conceptual analysis of autotrophy definitions.
- Review of biochemical literature on microbial growth media.
- Proposal of a refined definition for autotrophic organisms.
Main Results:
- Identified ambiguity in the current definition of autotrophy.
- Highlighted the confounding effects of secondary compounds in growth media.
- Proposed a revised definition focusing on the sole carbon source for anabolism.
Conclusions:
- A clear definition of autotrophy is crucial for accurate biochemical research.
- The proposed clarification distinguishes essential carbon sources from other media components.
- This refined definition will aid in the study of true autotrophs.
Related Concept Videos
01:28Microbial Nutrition
Organisms exhibit remarkable metabolic diversity, categorized based on how they acquire energy and carbon. These strategies enable survival in various ecological niches and are essential for maintaining energy flow and nutrient cycling within ecosystems.Energy and Carbon SourcesOrganisms are classified as phototrophs or chemotrophs based on energy acquisition. Phototrophs use light as their energy source, while chemotrophs rely on oxidizing chemical compounds. Further differentiation arises...
01:26Oxygenic Photosynthesis
Oxygenic photosynthesis is a fundamental process in which light energy is harnessed to drive the oxidation of water, leading to the production of molecular oxygen (O₂), adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH). This process is essential for sustaining aerobic life on Earth and is primarily carried out by cyanobacteria, algae, and plants. The core of oxygenic photosynthesis lies in the thylakoid membranes, where chlorophyll pigments facilitate light...
01:00What is Photosynthesis?
All living organisms on Earth are directly or indirectly dependent on photosynthesis. It is the only biological process that can capture energy from sunlight and convert it into chemical energy that every organism can use to power its metabolism. Photosynthesis is also the source of oxygen required by many living organisms.
Types of Organisms Based on their Modes of Nutrition
Broadly, there are two main categories of organisms based on their modes of nutrition — autotrophs and heterotrophs. An...
Types of Organisms Based on their Modes of Nutrition
Broadly, there are two main categories of organisms based on their modes of nutrition — autotrophs and heterotrophs. An...
00:39What is Photosynthesis?
Photosynthesis is a multipart, biochemical process that occurs in plants as well as in some bacteria. It captures carbon dioxide and solar energy to produce glucose. Glucose stores chemical energy in the form of carbohydrates. The overall biochemical formula of photosynthesis is 6 CO2 + 6 H2O + Light energy → C6H12O6 + 6 O2. Photosynthesis releases oxygen into the atmosphere and is largely responsible for maintaining the Earth’s atmospheric oxygen content.
01:15Metabolism of Chemolithotrophs
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation. However, because inorganic electron donors...
02:40Epiphytes, Parasites, and Carnivores
Plants often form mutualistic relationships with soil-dwelling fungi or bacteria to enhance their roots’ nutrient uptake ability. Root-colonizing fungi (e.g., mycorrhizae) increase a plant’s root surface area, which promotes nutrient absorption. While root-colonizing, nitrogen-fixing bacteria (e.g., rhizobia) convert atmospheric nitrogen (N2) into ammonia (NH3), making nitrogen available to plants for various biological functions. For example, nitrogen is essential for the biosynthesis of the...