Cycles In Nature

Question 1

Order of the water cycle

Answer 1

• evaporation. OR transpiration
• condensation
• precipitation

Question 2

What happens to carbon atoms when a plant photosynthesises ?

Answer 2

Carbon atoms from carbon dioxide become part of glucose molecules (which is stored as starch) in plants , when plants photosynthesise

Question 3

What happens to the carbon in the glucose ?

Answer 3

• some of the glucose will be broken down by the plant in respiration, The carbon in the glucose becomes part of the carbon dioxide molecules again, and is released back into the air.
• some of the carbon compounds in the plant will be eaten by animals. Animals respire, releasing some of it back into the air as carbon dioxide
• when the plant or animal dies, decomposers will feed on them. The carbon becomes part of the decomposes bodies. When they respire they release some carbon dioxide into the air again
• fossilisation can occur (The process when living things do not decay fully when they die due to the conditions in the soil). Fossil fuels are formed over millions of years by a process called looking in and when fossil fuels are burnt, carbon dioxide is released back into the atmosphere

Question 4

What processes pass nitrogen along food chains ?

Answer 4

Ingestion and assimilation

Question 5

The nitrogen cycle

Answer 5

• when a plant or animal dies it’s tissues decompose, mainly due to the activities of decay bacteria
• molecules containing nitrogen are broken down by the bacteria and ammonia is released into the soil
• ammonia is converted to nitrites and nitrates by nitrifying bacteria this is called nitrification
• plant root can only absorb the nitrates, they combined with carbohydrates (from photosynthesis) to form amino acid’s which are then made into proteins
• some nitrates are converted into N2 by denitrifying bacteria. This process is called Denitrification

Question 6

What is decomposition and what bacteria is involved ?

Answer 6

Protein in dead plants and animals are broken down. Ammonia is released into the soil
• decomposing bacteria

Question 7

What is nitrification and what bacteria is involved?

Answer 7

Ammonia is converted to nitrates

• nitrifying bacteria

Question 8

What is denitrification and what bacteria is involved ?

Answer 8

Nitrates are converted to nitrogen gas ( denitrification reduces the amount of nitrates that are in the soil and therefore makes it less fertile)
• denitrifying bacteria

Question 9

What is nitrogen fixation and what bacteria is involved ?

Answer 9

Nitrogen gas is converted to ammonia in bacteria which is used to make proteins, when the bacteria die the proteins decompose, releasing ammonia back into the soil
• nitrogen fixing bacteria which is found in root nodule of plants called legumes