Chapter 4.3 Carbon Cycling

Question 1

Understandings

Answer 1

1. Autotrophs convert CO2 into carbohydrates and other carbon compounds
2. In aquatic ecosystems carbon is present as dissolved CO2 and hydrogen carbonate ions
3. CO2 diffuses from the atmosphere or water into autotrophs
4. CO2 is produced by respiration and diffuses out of organisms into water or the atmosphere
5. Methane is produced from organic matter in anaerobic conditions by methanogenic archaens and some diffuses into the atmosphere or accumulates in the ground
6. Methane is oxidized to CO2 and H2O in the atmosphere
7. Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils
8. Partially decomposed organic matter from past geological ears was converted either into coal or into oil and gas which accumulates in porous rocks
9. Carbon dioxide is produced by the combustion of biomass and fossilized organic matter
10. Animals such as reef-building corals and molluscs have hard parts that are composed of calcium carbonate and can become fossilized in limestone

Question 2

Carbon

Answer 2

crucial element to living organisms, life on Earth is carbon-based. Carbon found in biosphere in organic molecules such as carbohydrates, proteins, lipids and vitamins, but also found in the atmosphere (CO2)

Question 3

biosphere

Answer 3

all places where life is found

Question 4

litosphere

Answer 4

refers to all the places where rocks are found

Question 5

Petroleum

Answer 5

gasoline, kerosene, and plastics are made of it. Rich in carbon because it originated from partially decomposed organisms that died millions of years ago

Question 6

Giraffe carbon example

Answer 6

The carbon atoms that make up the cells of flesh and blood of giraffe come from the vegetation it ate. Eating organic material provides newly dividing cells in the giraffe’s body with a fresh supply of carbon-based energy-rich molecules with which the cells can carry out work. When cellular respiration is complete, CO2 is released in atmosphere.