Nutrient Cycles Gr.9

Question 1

What is the carbon cycle?

Answer 1

The carbon cycle is a biogeochemical process by which carbon is exchanged in the atmosphere, land, water, and living organisms.

Question 2

Why is carbon essential to life?

Answer 2

Carbon allows atoms to form complex bonds like carbohydrates, proteins, lipids, and nucleic acids.

Question 3

What process do plants use to absorb carbon dioxide from the atmosphere?

Answer 3

Photosynthesis.

Question 4

What is the role of decomposers in the carbon cycle?

Answer 4

Decomposers break down dead organic matter, returning carbon to the soil and atmosphere.

Question 5

What are carbon reservoirs/sinks?

Answer 5

Carbon reservoirs are natural systems that absorb more carbon than they release, such as forests and oceans.

Question 6

What human activities impact the carbon cycle?

Answer 6

Human activities such as burning fossil fuels and deforestation impact the carbon cycle.

Question 7

What is the Nitrogen Cycle?

Answer 7

The Nitrogen Cycle is a biogeochemical process through which nitrogen is converted into many forms, and passes through the atmosphere, soil, and living organisms.

Question 8

What is Nitrogen Fixation?

Answer 8

Nitrogen fixation is a process where nitrogen gas from the air is turned into a form that plants can use.

Question 9

True or False: N₂ (nitrogen gas) in the atmosphere isn’t usable by most living organisms.

Answer 9

True.

Question 10

Why do plants and animals need nitrogen?

Answer 10

Plants and animals need nitrogen because nitrogen is a vital part of proteins, which are necessary for cells to function.

Question 11

Bacteria turn N₂ (nitrogen gas) into a usable form for plants which may be ________

Answer 11

NO₂- (Nitrites,)
NO₃- (Nitrates,)
or NH₃ (ammonia)

Question 12

NO₂-, NO₃-, and NH₃ are __________

Answer 12

Nitrogen Compounds.

Question 13

Nitrifying Bacteria vs. Denitrifying Bacteria

Answer 13

Nitrifying bacteria convert ammonia (NH₃) into nitrites, (NO₂-) and then into nitrates (NO₃-) to feed plants.
Denitrifying bacteria do the opposite. They convert nitrates (NO₃-) back into nitrogen gas (N₂), which is released into the atmosphere. (So there is a balance of nitrogen.)

Question 14

Decomposition meaning:

Answer 14

Decomposition is the process where decomposers decompose organic matter into simpler substances such as water, carbon dioxide, and other minerals.

Question 15

Condensation meaning:

Answer 15

The conversion of water vapour to liquid.

Question 16

Evaporation meaning:

Answer 16

The conversion of liquid into gas.

Question 17

Precipitation

Answer 17

Rain, snow, or hail that falls to the ground from clouds.

Question 18

Transpiration

Answer 18

The process by which plants give off water vapour.

Question 19

Parasitism

Answer 19

A relationship in which one organism (the parasite) benefits at the expense of another organism (the host), typically causing harm to the host.

Question 20

Mutualism

Answer 20

A relationship where both organisms benefit.

Question 21

Commensalism

Answer 21

A relationship where one organism benefits without affecting the other.

Question 22

How does phosphorus enter the ocean?

Answer 22

Over time, weathering and erosion release phosphate ions into the soil and water.

Question 23

How do plants and animals receive phosphorus?

Answer 23

Through plant uptake. Plants absorb phosphate from the soil through their roots, and then animals eat the plants.

Question 24

How does phosphorus return to the environment?

Answer 24

Decomposers break down the organic matter, returning the phosphate back into the soil.

Question 25

Eutrophication

Answer 25

When too much nutrients accumulate in a body for water, leading to excessive growth of a simple plant, like algae.
Example: Too much algae on the top of a body of water can block sunlight from reaching other organisms.

Question 26

Photosynthesis word equation

Answer 26

Carbon dioxide + Water → Glucose + Oxygen

Question 27

Cellular respiration word equation

Answer 27

Glucose + Oxygen → Carbon dioxide + Water + Energy

Question 28

Explain the CARBON CYCLE to a 5 year old child.

Answer 28

The carbon cycle starts with plants taking in air (carbon) to grow. Animals eat plants and breathe it out. When plants and animals die, the carbon goes into the ground. People can burn it (for example gasoline in a car,) and it goes back into the air. Then plants take it in again, and the cycle repeats.