The Carbon Cycle & Decomposition

Question 1

Compound

2 marks

Answer 1

A substance formed by the chemical union of 2 or more elements.

Question 2

Decompose

2 marks

Answer 2

If a substance decomposes, it breaks down into simpler compounds or elements.

Question 3

Food chain

3 marks

Answer 3

A sequence (usually shown as a diagram) of feeding relationships between organisms

• showing which organisms eat what and the movement of energy through trophic levels.

Question 4

Inorganic

1 mark

Answer 4

Not derived from living matter.

Question 5

Molecule

2 marks

Answer 5

A collection of 2 or more atoms held together by chemical bonds.

Question 6

Organic

1 mark

Answer 6

Derived from living matter.

Question 7

Secrete

2 marks

Answer 7

To release a substance, in this case an enzyme.

Question 8

Nutrient Cycles

6 marks

Answer 8

Within an ecosystem;

Nutrients - begin as simple inorganic compounds (CO2 and nitrate ions)

• taken in by a plant and used to make more complex biological molecules.

Molecules - passed along the food chains.
When plants + animals die = complex biological molecules decomposed.

Question 9

Where do nutrients begin as simple inorganic compounds?

1 mark

Answer 9

Within an ecosystem.

Question 10

What do nutrients begin as in the ecosystem?

2 marks

Answer 10

Simple inorganic compounds.

CO2 + Nitrate ions

Question 11

What are taken in by a plant + used to make more complex biological molecules?

(2 marks)

Answer 11

Simple inorganic compounds

CO2 + Nitrate Ions

Question 12

What take in Simple inorganic compounds (CO2 + Nitrate Ions)?

(1 mark)

Answer 12

A plant

Question 13

Why does a Plant take in Simple Inorganic Compounds such as CO2 + Nitrate Ions?

(2 marks)

Answer 13

To make more Complex Biological Molecules

• that can be passed along the food chains.

Question 14

How do Complex Biological Molecules transfer to animals if originally produced by plants?

(1 mark)

Answer 14

Passing along the food chain

in food consumed by animal

Question 15

What happens to Complex Biological Molecules once an Organism dies?

(2 marks)

Answer 15

They decompose

• plants can then absorb + reuse these simple compounds, completing the cycle.

Question 16

Decomposition of organisms

3 marks

Answer 16

The process by which bacteria + fungi break dead organisms into their simple compounds

• after they have decayed.

Question 17

Decay

2 marks

Answer 17

The process in which dead organisms are broken down into smaller pieces

-organisms such as earthworms are involved in this process.

Question 18

Decomposing bacteria + fungi are described as…

1 mark

Answer 18

Saprophytic

Question 19

What do plants do with the Simple Compounds produced after Complex Biological Molecules are decomposed?

(2 marks)

Answer 19

Absorb + reuse the compounds.

Question 20

Why are decomposing bacteria + fungi described as saprophytic

(1 mark)

Answer 20

because of the way they break down dead organic matter.

Question 21

Saprophytic nutrition involves:

4 marks

Answer 21

Bacteria/fungi secreting enzymes out of their cells into the soil or dead organism

• enzymes digest the organic material (extracellular digestion)
• products of digestion are absorbed by the bacteria/fungi.

Question 22

The enzymes digest the organic material during ‘Saprophytic Nutrition’
what is the name of this process?

(1 mark)

Answer 22

Extracellular Digestion

Question 23

Where do the Enzymes digest organic matter during the Saprophytic process? (Extracellular digestion)

(1 mark)

Answer 23

Outside the cells.

Question 24

Extracellular digestion;
Explained

(6 marks)

Answer 24

Process in which Saprobionts feed by secreting enzymes through the cell membrane onto food

• Enzymes catalyse the digestion of food into molecules small enough to be taken up by passive Diffusion, transport of phagocytosis.

Question 25

Extracellular digestion;
Simplified

(2 marks)

Answer 25

Enzymes digest organic material outside the cells.

Question 26

Humus

2 marks

Answer 26

Organic content of the soil formed from decomposing plants + animals.

Question 27

Bacteria/fungi secretes, what, out of their cells into the soil or dead organism - in the Saprophytic process?

(1 mark)

Answer 27

Enzymes

Question 28

What are the products of digestion absorbed by - during the Saprophytic process?

(2 marks)

Answer 28

Bacteria/fungi

Question 29

Ideal conditions for decomposition (so it happens quickly)

3 marks

Answer 29

Temperature is warm

Enough moisture

Decomposing organism has a large surface area.

Question 30

What is the ideal temp for decomposition?

1 mark

Answer 30

Warm

Question 31

What conditions cause the rate of decomposition to decrease?

1 mark

Answer 31

Anaerobic conditions

little/no O2 available - E.g waterlogged soil

Question 32

What is a major component in Carbs, Fats + Proteins?

1 mark

Answer 32

Carbon

Question 33

Carbon is a major component in

3 marks

Answer 33

Carbs, fats + proteins.

Question 34

The Carbon Cycle

3 marks

Answer 34

Involves the exchange of Carbon between living organisms (biotic) + their atmosphere (abiotic).

Question 35

In the cycle, what is constantly removed from, + returned to, the environment?

(1 mark)

Answer 35

Carbon

Question 36

A balanced ______ cycle is essential?

1 mark

Answer 36

Carbon

Question 37

Processes involved in the carbon cycle are:

8 marks

Answer 37

• Photosynthesis
• Feeding
• Respiration
• Fossilisation
• Combustion
• Excretion
• Egestion
• Decomposition

Question 38

Photosynthesis in the Carbon Cycle;

3 marks

Answer 38

Plants absorb CO2 from atmosphere + form it into sugar, starch + other organic compounds.

This is the only process in the cycle that decreases the level of CO2 in the atmosphere.

Question 39

Feeding in the Carbon Cycle;

2 marks

Answer 39

Moves carbon in the form of biological molecules along the food chain.

Question 40

Respiration in the Carbon Cycle;

3 marks

Answer 40

When living organisms (plants, animals and decomposers) respire they release CO2 into the atmosphere

-this is a form of excretion.

Question 41

Fossilisation in the Carbon Cycle;

4 marks

Answer 41

If conditions are not favourable for the process of decomposition - dead organisms decay slowly or not at all.

These organisms build up + if compressed over millions of years, can form fossil fuels (coal, oil or gas).

Question 42

Combustion in the Carbon Cycle;

2 marks

Answer 42

Burning of fossil fuels releases stored CO2 into the atmosphere.

Question 43

Excretion in the Carbon Cycle;

2 marks

Answer 43

When waste is removed from the body (urine)

• this excreted material can be broken down during the process of decomposition.

Question 44

Egestion in the Carbon Cycle;

3 marks

Answer 44

Removal of faeces from an animal that will contain carbon

• this egested material can be broken down during the process of decomposition.

Question 45

Decomposition in the Carbon Cycle;

3 marks

Answer 45

When complex, carbon compounds in dead organisms, urine + faeces are broken down into simpler carbon compounds - by bacteria or fungi.