Biochemical Cycles Flashcards
What are Biochemical Cycles?
- Include biological organisms & geological processes= includes processes that occur on many spatial scales from cellular to planetary
- Arise from a fixed number of atoms of each type of element
Carbon is the major…
Constituent of the bodies of organisms
What is carbon the major constituent of the bodies of organisms?
- BC carbon atoms help form the framework of all organic compounds
- Almost 20% of weight of human body is carbon
What is the most significant carbon-containing compound?
- CO2
- It makes up .03% of the volume of the atmosphere
- And it reacts spontaneously with water to form bicarbonate ions (HCO3-)
What are Biogeochemical cycles?
- Emphasize that the cycles of chemical elements involve biological processes & organisms, & geological (abiotic) systems & processes
- They cross the boundaries of ecosystems
What do Biogeochemical cycles include?
- Include processes that occur on many spatial scales from cellular to planetary
- They also include processes that occur on multiple time scales= biochemical reactions (secs) to the weathering of rocks (millennia)
What is the most significant carbon-containing compound in abiotic environments of organisms?
-Carbon dioxide= makes up .03% of the volume of the atmosphere= 750 billion metric tons
How does CO2 react with water?
-It reacts spontaneously w/ water to form bicarbonate ions= HCO3-
How is the carbon cycle like in terrestrial ecosystems?
- Plants & other photosynthetic organisms take in CO2 from the atmosphere & use it in photosynthesis to synthesize the carbon-containing organic compounds
- This is sometimes called carbon fixation
What does Fixation refer to?
-The metabolic reactions that make nongaseous compounds from gaseous ones
How do photosynthetic plants & animals obtain energy?
-They both break down some of the organic compounds available to them via aerobic cellular respiration
How is the carbon cycle in aquatic ecosystems?
- It is similar to the process for terrestrial ecosystems
- BUT inorganic carbon is present in the water has CO2 & HCO3- ions
What does CO2 & HCO3- have in common?
- They both are present in the water of aquatic ecosystems
- They both act as sources of carbon for photosynthesis by algae & aquatic plants
What kind of microbes provide an additional dimension to the global carbon cycle?
-Microbes that break down organic compounds by anaerobic cellular respiration
What are Methanogens?
-They are microbes that produce methane CH4
What is a major source for Methane?
-Wetland ecosystems bc methogens live in oxygen free sediments
What happens to Methane when it enters the atmosphere?
- It is oxidized abiotically to CO2
- BUT the CH4 that remains isolated from oxygen can last for a lot of time
What are the 2 dimensions of the global carbon cycle?
- Microbes that break down organic compounds
- And that some parts of the cycle may proceed faster than others
What effect would different parts of the global carbon cycle proceeding faster than other parts?
-There will be an imbalance of the cycle which can cause burned fossil fuels to rapidly return to the atmosphere= higher concentration of CO2 levels= global warming