22.3 Prokaryotic Metabolism
2 min read•june 14, 2024
Prokaryotes are essential for life on Earth, playing crucial roles in nutrient cycling and energy acquisition. These tiny organisms have diverse metabolic strategies, allowing them to thrive in various environments and contribute to global ecological processes.
From photosynthetic to chemoheterotrophic decomposers, prokaryotes drive key biogeochemical cycles. They transform essential elements like carbon, nitrogen, and sulfur, making them available to other organisms and maintaining the delicate balance of ecosystems worldwide.
Prokaryotic Macronutrients and Metabolism
Essential macronutrients for prokaryotes
Top images from around the web for Essential macronutrients for prokaryotes
Unique Characteristics of Prokaryotic Cells · Microbiology View original
Is this image relevant?
Prokaryotic Metabolism | Boundless Biology View original
Is this image relevant?
Prokaryotic Metabolism | Boundless Biology View original
Is this image relevant?
Unique Characteristics of Prokaryotic Cells · Microbiology View original
Is this image relevant?
Prokaryotic Metabolism | Boundless Biology View original
Is this image relevant?
1 of 3
Top images from around the web for Essential macronutrients for prokaryotes
Unique Characteristics of Prokaryotic Cells · Microbiology View original
Is this image relevant?
Prokaryotic Metabolism | Boundless Biology View original
Is this image relevant?
Prokaryotic Metabolism | Boundless Biology View original
Is this image relevant?
Unique Characteristics of Prokaryotic Cells · Microbiology View original
Is this image relevant?
Prokaryotic Metabolism | Boundless Biology View original
Is this image relevant?
1 of 3
- Carbon
- Builds organic molecules (proteins, nucleic acids, lipids)
- Obtained from organic compounds or fixed from inorganic CO2
- Nitrogen
- Essential for amino acids, nucleic acids, other biomolecules
- Obtained from organic compounds or fixed from inorganic N2
- Phosphorus
- Synthesizes nucleic acids (DNA, RNA), phospholipids
- Transfers energy (ATP, GTP)
- Sulfur
- Component of amino acids (cysteine, methionine), cofactors
- Obtained from organic compounds or inorganic sulfate
- Other essential elements in smaller quantities
- Potassium, magnesium, calcium, iron
- Enable enzyme function, cell structure, various metabolic processes
Energy acquisition in prokaryotes
- obtains energy from light
- Photosynthetic prokaryotes () use light to fix carbon
- obtains energy from chemical compounds
- fix inorganic CO2 using energy from inorganic compounds
- obtain carbon and energy from organic compounds
- derives energy from inorganic compounds
- Sulfur-oxidizing bacteria, hydrogen-oxidizing bacteria, ammonia-oxidizing archaea
- obtains energy and carbon from organic compounds
- Includes and or
Prokaryotic Energy Metabolism
- : Initial glucose breakdown pathway common to most prokaryotes
- : Uses oxygen as final electron acceptor
- generates proton gradient
- produces ATP using proton gradient
- Anaerobic respiration: Uses alternative electron acceptors (e.g., nitrate, sulfate)
- Fermentation: ATP production without external electron acceptors
Prokaryotes in global nutrient cycles
- Carbon cycle
- Photosynthetic prokaryotes (cyanobacteria) fix atmospheric CO2, contributing to primary production
- Chemoheterotrophic prokaryotes decompose organic matter, releasing CO2
- produce methane (CH4) during anaerobic respiration, a potent greenhouse gas
- Nitrogen cycle
- : Prokaryotes () convert atmospheric N2 into ammonia (NH3), making it bioavailable
- : Ammonia-oxidizing bacteria and archaea convert NH3 to nitrite (NO2-), nitrite-oxidizing bacteria convert NO2- to nitrate (NO3-)
- : Prokaryotes reduce NO3- back to atmospheric N2 under anaerobic conditions
- : Prokaryotic decomposition of organic matter releases NH3, used by plants or undergoes nitrification
- Prokaryotes make essential elements bioavailable, maintain ecosystem balance through nutrient cycling
Key Terms to Review (27)
Aerobic: Aerobic refers to processes or organisms that require oxygen to survive and grow. In prokaryotes, aerobic respiration is a key metabolic pathway for energy production.
Aerobic respiration: Aerobic respiration is a biological process in which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. This process is essential for organisms that require oxygen to efficiently produce energy, and it involves several key stages, including glycolysis, the oxidation of pyruvate, and the citric acid cycle, along with oxidative phosphorylation. The ability to perform aerobic respiration allows organisms to maximize energy yield from nutrients, making it a crucial mechanism for energy metabolism.
Ammonification: Ammonification is the biological process by which organic nitrogen compounds are converted into ammonia by microorganisms, primarily bacteria and fungi. This process is a critical component of the nitrogen cycle, facilitating the transformation of nitrogen in organic matter back into a form that can be utilized by plants and other organisms.
Anaerobic Respiration: Anaerobic respiration is a metabolic process that occurs in the absence of oxygen, allowing organisms to convert glucose into energy. This process is essential for many prokaryotic organisms and some eukaryotes, enabling them to thrive in environments where oxygen is limited or unavailable. Anaerobic respiration results in the production of energy and various byproducts, which can include lactic acid or ethanol, depending on the organism and the specific pathway utilized.
Biological nitrogen fixation: Biological nitrogen fixation is the process by which certain prokaryotes convert atmospheric nitrogen (N₂) into ammonia (NH₃), making it available for use by plants. This process is crucial for the nitrogen cycle and supports plant growth in ecosystems.
Chemoautotrophs: Chemoautotrophs are organisms that obtain their energy by oxidizing inorganic substances and use this energy to convert carbon dioxide into organic compounds. These unique organisms play a crucial role in the ecosystem by utilizing energy from chemical reactions, primarily in environments where sunlight is not available, such as deep-sea vents or sulfur-rich hot springs.
Chemoheterotrophs: Chemoheterotrophs are organisms that obtain their energy and carbon by consuming organic compounds. They play a crucial role in ecosystems by breaking down complex organic materials, which recycles nutrients and supports various food webs. This group includes many prokaryotic organisms, which are essential for nutrient cycling and energy flow in both terrestrial and aquatic environments.
Chemotrophs: Chemotrophs are organisms that obtain energy by the oxidation of electron donors in their environments. These electron donors can be organic or inorganic molecules.
Chemotrophy: Chemotrophy is a type of metabolism where organisms obtain energy by oxidizing chemical compounds. This process is crucial for prokaryotic metabolism, allowing bacteria and archaea to thrive in various environments by using organic or inorganic substances as energy sources, instead of relying on sunlight.
Cyanobacteria: Cyanobacteria are a phylum of bacteria that obtain their energy through photosynthesis. They are often referred to as 'blue-green algae' due to their color and aquatic habitats.
Cyanobacteria: Cyanobacteria are a phylum of photosynthetic bacteria known for their ability to perform oxygenic photosynthesis, contributing significantly to the Earth's oxygen supply. These microorganisms, often referred to as blue-green algae, play a crucial role in aquatic ecosystems and are important for the nitrogen cycle due to their nitrogen-fixing capabilities.
Denitrification: Denitrification is a microbial process in which nitrates (NO₃⁻) and nitrites (NO₂⁻) are reduced to nitrogen gas (N₂) or, to a lesser extent, nitrous oxide (N₂O), ultimately releasing nitrogen back into the atmosphere. This process is essential for the nitrogen cycle, helping to maintain the balance of nitrogen in the ecosystem and preventing the accumulation of excess nitrates in the environment.
Electron transport chain: The electron transport chain (ETC) is a series of protein complexes and other molecules located in the inner mitochondrial membrane that transfer electrons from electron donors to electron acceptors via redox reactions, ultimately generating adenosine triphosphate (ATP) through oxidative phosphorylation. It plays a critical role in energy metabolism and cellular respiration, connecting various metabolic processes.
Fermentation: Fermentation is a metabolic process that converts sugars into acids, gases, or alcohol in the absence of oxygen. This process allows organisms to generate energy anaerobically, playing a crucial role in energy production for various living systems and influencing numerous biological functions.
Glycolysis: Glycolysis is the metabolic pathway that converts glucose into pyruvate, releasing energy and producing ATP. It takes place in the cytoplasm of the cell and does not require oxygen.
Glycolysis: Glycolysis is a metabolic pathway that converts glucose into pyruvate, generating small amounts of energy in the form of ATP and NADH. This process occurs in the cytoplasm of cells and serves as a fundamental step in cellular respiration, connecting carbohydrate metabolism with energy production.
Lithoautotrophy: Lithoautotrophy is a type of metabolic process in which organisms, primarily certain bacteria and archaea, utilize inorganic compounds as their primary energy source and carbon dioxide as their carbon source to produce organic matter. This process is crucial for the survival of these organisms in environments where organic matter is scarce, enabling them to thrive in extreme conditions like deep-sea hydrothermal vents or mineral-rich soils.
Macronutrients: Macronutrients are essential nutrients required by living organisms in large quantities to support their growth, metabolism, and overall health. They include carbohydrates, proteins, and lipids, each playing crucial roles in various biological processes, from energy production to cellular structure. Understanding macronutrients is key to comprehending how different organisms, such as plants and prokaryotes, acquire and utilize these nutrients for their survival and functioning.
Methanogenic archaea: Methanogenic archaea are a group of microorganisms that produce methane as a metabolic byproduct in anoxic conditions. These unique organisms play a crucial role in the global carbon cycle, particularly in environments where oxygen is absent, such as wetlands, the guts of ruminants, and deep-sea sediments.
Nitrification: Nitrification is the biological process by which ammonia is converted into nitrites and then into nitrates, primarily through the activity of specific prokaryotic microorganisms. This two-step process plays a crucial role in the nitrogen cycle, enabling the transformation of nitrogen from organic sources into forms that can be readily utilized by plants and other organisms. Nitrification is essential for soil fertility and the overall health of ecosystems, linking microbial metabolism with nutrient cycling in the environment.
Nitrogen fixation: Nitrogen fixation is the process by which atmospheric nitrogen ($$N_2$$) is converted into a form that living organisms can use, typically ammonia ($$NH_3$$). This essential biochemical process enables the incorporation of nitrogen into organic compounds, which is crucial for the growth and development of plants and other organisms.
Nutrients: Nutrients are substances that provide the essential elements required for growth, energy, and cellular function. In prokaryotes, nutrients are crucial for metabolic processes and maintaining cellular activities.
Organoheterotrophy: Organoheterotrophy is a metabolic process in which organisms obtain carbon and energy by consuming organic compounds. This term highlights the ability of certain prokaryotes to rely on organic materials, rather than inorganic sources like carbon dioxide, for growth and energy production. This strategy allows these organisms to thrive in various environments, especially those rich in organic matter.
Oxidative phosphorylation: Oxidative phosphorylation is the final stage of cellular respiration where ATP is produced through the electron transport chain and chemiosmosis. This process involves the transfer of electrons from NADH and FADH2 to oxygen, creating a proton gradient that drives ATP synthesis in mitochondria.
Phototrophs: Phototrophs are organisms that obtain energy from light to synthesize organic compounds. They play a crucial role in ecosystems by supporting the food chain and contributing to the oxygen supply through photosynthesis.
Phototrophy: Phototrophy is the process by which organisms capture light energy and convert it into chemical energy, typically through photosynthesis. This ability is crucial for many prokaryotic organisms, allowing them to harness sunlight to produce organic compounds from carbon dioxide, which in turn fuels their metabolism and growth. Phototrophy plays a significant role in the energy dynamics of ecosystems, particularly through the contributions of photosynthetic prokaryotes like cyanobacteria.
Rhizobium: Rhizobium is a genus of soil bacteria that are known for their ability to form symbiotic relationships with leguminous plants, enabling them to fix atmospheric nitrogen into a form that plants can use. This relationship not only benefits the plants by enhancing their nitrogen supply but also plays a crucial role in improving soil fertility and health.