Carbon and nitrogen cycles

Question 1

What is an ecosystem?

Answer 1

A community of organisms living in an area as well as the nonliving, abiotic, conditions.

Question 2

What is a biotic component of an ecosystem?

Answer 2

A living organism

Question 3

Materials that organisms need to survive, such and carbon and nitrogen, are recycled through which components of ecosystems?

Answer 3

Biotic and abiotic

Question 4

What is an abiotic component of an ecosystem?

Answer 4

Nonliving components such as air, rocks and soil

Question 5

What is meant by ‘recycled’ in terms of the carbon cycle?

Answer 5

There is only a fixed amount of carbon in the world, therefore it is in a continuous cycle

Question 6

The carbon cycle is powered by what?

Answer 6

Photosynthesis

Question 7

Green plants use the carbon from CO2 to make………

Answer 7

Carbohydrates
Lipids
Proteins

Question 8

Eating the green plants passes the carbon compounds along to………..

Answer 8

Animals

Question 9

What is carried out by living plants and animals that releases CO2 back into the air?

Answer 9

Respiration

Question 10

When animals and plants die, they decay, and are broken down by micro organisms and eventually turn into………

Answer 10

Fossil fuels

Question 11

What are the micro organisms that breakdown decomposing animals and plants called?

Answer 11

Decomposers

Question 12

Give two examples of micro organisms that are decomposers?

Answer 12

Bacteria
Fungi

Question 13

What do the microorganisms, known as decomposers, release?

Answer 13

Enzymes, which catalyse the breakdown of dead material into smaller molecules and CO2 back into the air

Question 14

When some useful plant and animal products, such as wood and fossil fuels, are burnt what is released into the air?

Answer 14

CO2

Question 15

What percentage of our atmosphere is nitrogen gas?

Answer 15

About 78%

Question 16

What is Nitrogen needed for?

Answer 16

Making proteins for growth

Question 17

Where do plants get their nitrogen from?

Answer 17

The soil

Question 18

What does the nitrogen in the air have to be turned into four plants can use it?

Answer 18

Nitrogen compounds such as nitrates

Question 19

Where do animals get their proteins from?

Answer 19

Eating plants or eating each other

Question 20

What is nitrogen fixation?

Answer 20

It is the process of turning N2 from the air into nitrogen compounds in the soil which plants can use

Question 21

What are the two main ways nitrogen fixation can happen?

Answer 21

Lightning - The energy in a bolt of lightning makes Nitrogen react with oxygen in the air to give nitrates.
Nitrogen fixing bacteria - found in soil and the roots of some plants

Question 22

Name the four different types of bacteria involved in the nitrogen cycle

Answer 22

Decomposers
Nitrifying bacteria
Nitrogen fixing bacteria
Denitrifying bacteria

Question 23

What do decomposers do?

Answer 23

Breakdown proteins and urea and turn them into ammonia. This forms ammonium ions in the soil.

Question 24

What do nitrifying bacteria do?

Answer 24

Turn ammonium ions in decaying matter into nitrates (nitrification)

Question 25

What do nitrogen-fixing bacteria do?

Answer 25

Turn atmospheric N2 into nitrogen compounds that plants can use

Question 26

What does denitrifying bacteria do?

Answer 26

Turn nitrates back into N2 gas. This is of no benefit to living organisms.