Chapter 4 - Carbon Cycle

Question 1

What is the current carbon dioxide concentration of the atmosphere at the moment?

Answer 1

0.039%

Question 2

And aquatic habitats How is carbon dioxide present?

Answer 2

As a dissolved gas and hydrogen carbonate ions

Question 3

What is absorbed by aquatic plants and other autotrophs that live in water?

Answer 3

Dissolved co2 and hydrogen carbonate ions

Question 4

How does carbon dioxide diffuse from the atmosphere?

Answer 4

Because autotrophs use carbon dioxide in the production of carbon compounds by photosynthesis

Question 5

What is produced by respiration?

Answer 5

Carbon dioxide and diffuses out of organisms into water or the atmosphere

Question 6

What is co2 a waste product of?

Answer 6

Aerobic cell respiration

Question 7

Co2 is a waste product of aerobic cell respiration- it is produced in all cels that carry out this respiration - what are the 3 groups that do it?

Answer 7

1) non-photosynthetic cells in producers for example root cells in plants
2) animal cells
3) saprotrophs such as fungi that decompose dead organic matter

Question 8

What is methane produced from?

Answer 8

Methane is produced from organic matter in anaerobic conditions By methanogenic archaens and some diffuse into the atmosphere

Question 9

What are the 3 groups of anaerobic prokararyotes that have methane as a waste product?

Answer 9

1) bacteria that convert organic matter
2) bacteria that use the organic acids and alcohol
3) archaens that produce methane from 2 different chemical reactions

Question 10

Where do archaea a that are methanogenic carry out methanogenesis ? (4)

Answer 10

1) mud along shores
2) swamps, wetlands etc
3) guts of termites
4) landfill sites where organic matter is in wastes that have been buried

Question 11

What is methane oxidised to?

Answer 11

Carbon dioxide and water in the atmosphere

Question 12

Why are atmopheric conditions not high in methane?

Answer 12

Molecules of methane released into the atmosphere only last there on average for 12 years

Question 13

Why does peat form?

Answer 13

When organic matter is not fully decomposed because of anaerobic conditions in waterlogged soils

Question 14

Why is organic matter sometimes not fully deoxmposed

Answer 14

In some environments water is unable to drain out of soils so they become water logged and anaerobic (saprotrophs thrive in aerobic conditions) - so cannot thrive and acidic conditions tend to develop

Question 15

Carbon and some compounds of carbon are chemically very stable and can remain unchanged in rocks for hundreds of years - where are they kept?

Answer 15

There are large deposits - result of incomplete decomposition of organic matter and its burial in sediments that become rock

Question 16

How is coal formed?

Answer 16

When deposits of peat are buried under other sediments- pears are compressed and heated, gradually turning to coal

Question 17

How is oil and natural gas formed?

Answer 17

In the mud at the bottom of seas and lakes - conditions are usually anaerobic and so decomposition is often incomplete - as more mud and other sediments are deposited all becomes compressed and heated- chemical changes occur, which produces complex mixtures of liquid carbon compounds or gases

Question 18

What is a way of carbon dioxide being produced?

Answer 18

By the combustion of biomass and fossilised organic matter

Question 19

What is combustion

Answer 19

Organic matter is heated to its ignition temperature in the presence of oxygen = combustion

Question 20

What are the products of complete combustion?

Answer 20

Carbon dioxide and water

Question 21

What are the three forms of fossilised organic matter?

Answer 21

Coal, oil and natural gases - all burned as fuels

Question 22

What type of animals can become fossilised and why?

Answer 22

Reef-building corals and molluscs have hard parts that are composed of calcium carbonate and can become fossilised in limestone

Question 23

How much limestone is all sedimentary rocks and how much carbon is locked up in. It?

Answer 23

10%

12%

Question 24

What does the mAuna loa observatory do

Answer 24

Produces large amounts of data which can be used for analysis

Question 25

What can autotrophs concert carbon dioxide into?

Answer 25

Carbohydrates another carbon compounds