4.3 Carbon cycling Flashcards
What do autotrophs convert carbon dioxide into?
Autotrophs absorb carbon dioxide from the atmosphere and convert it into carbohydrates, lipids and all the other carbon compounds that they require
What does autotrophs absorbing carbon dioxide do to the atmosphere?
This has the effect of reducing the carbon dioxide concentration of the atmosphere
* there is a lower concentration of CO2 in earths surface where photosynthesis rates are high
What is carbon fixation?
The incorporation of carbon into organic compounds by living organisms, chiefly by photosynthesis in green plants.
Is carbon dioxide soluble in water?
Yes
Is carbon dioxide soluble in water?
Yes
How is carbon dioxide presented in aquatic habitats?
As dissolved gas and hydrogen carbonate ions
How is carbonic acid formed?
When CO2 combine with water
What does carbonic acid formed when dissociated?
Hydrogen and hydrogen carbonate ions (H+ and HCO3-)
* this explains how carbon dioxide can reduce the pH of water
What do aquatic plants and other autotrophs that live in water absorb?
Dissolves to carbon dioxide and hydrogen carbonate ions
* to make carbohydrates and other carbon compounds
How does autotrophs reduce the concentration of carbon dioxide inside them?
Autotrophs use carbon dioxide in the production of carbon compounds by photosynthesis or other processes
How is carbon dioxide able to diffuse from the atmosphere or water into autotrophs?
Due to a concentration gradient between cells in autotrophs and the air or water around
* Set up by lower concentrations in autotrophs since they use them
What does diffusion usually happen in land plants?
Through stomata in the underside of the leaves
How does carbon dioxide diffuse into aquatic plants?
The entire surface of the leaves and stems is usually permeable to CO2, so diffusion can be through any part of these parts of the plant
How is carbon dioxide produced and where does it diffuse to?
By respiration and diffuse out of organims into water or the atmosphere
What is a waste product of aerobic cell respiration?
Carbon Dioxide
What produces methane?
Methane is produced from organic matter in anaerobic conditions by methanogenic archaens
Where is methane widely produced in?
Is produced widely in anaerobic environments, as its a waste product of a type of anaerobic respiration
What are the 3 different groups of anaerobic prokaryotes involved in the production of methane?
- Bacteria that convert organic matter into a mixture of organic acids, alcohol, hydrogen and carbon dioxide
- Bacteria that use the organic acids and alcohol to produce acetate, carbon dioxide and hydrogen
- Archeans that produce methane from carbon dioxide, hydrogen and acetate.
What does bacteria that convert organic matter convert it into?
A mixture of organic acids, alocohol, hnydrogen and carbon dioxide
What does bacteria that use the organic acids and alocohol produce?
Acetate, carbond dioxide and hydrogen
How does archeans produce methane?
From carbon dioxide, hydrogen and acetate. They do this by two chemical reactions
* CO2 + 4H2 -> CH4 + 2H2O
* CH3COOH -> CH4 + CO2
What does being methanogenic mean?
Being able to carry out methanogenesis
What are some anaerobic environments that archaeans carry out methanogenisis in?
- Mud along the shores and in the bed of lakes
- Swamps, mires, mangrove forests and other wetlands where the soil or peat deposits are waterlogged
- Guts of termites and of ruminant mammals such as cattle and sheep
- Landfill sites where organic matter is in wastes that have been buried
Where does the methane produced by archaens in anaerobic environments go?
Some diffuses into the atmosphere