Nutrient Cycles Flashcards
(42 cards)
What is meant by a carbon sink?
Something that takes up, locks up, or stores carbon or carbon dioxide for a long time.
Give an example of a carbon sink.
Peat, coal, limestone, trees, fossil fuels, chalk, or shells.
What is global warming?
An increase in Earth’s surface or mean global temperature.
Which gas contributes to global warming?
Carbon dioxide, a greenhouse gas.
How do greenhouse gases cause warming?
They trap or reflect back heat (long wave or infrared radiation) in the atmosphere.
What is this effect called?
The increased or enhanced greenhouse effect.
Name a consequence of global warming.
Melting ice caps, flooding, or climate change.
What do saprobionts do in the nitrogen cycle?
Use enzymes to decompose proteins, DNA, RNA, and urea.
What do saprobionts release during decomposition?
Ammonia or ammonium ions.
How do saprobionts/fungi digest carbon compounds in fallen pine leaves?
By extracellular digestion using secreted enzymes.
How do saprobionts/fungi use the digested products?
They absorb soluble products.
What do they use these products for?
To synthesize structural compounds or named compounds.
How do saprobionts gain energy for growth?
Through respiration.
What happens to proteins and amino acids in the soil?
They are broken down.
Which process releases ammonium compounds?
Deamination or ammonification.
Which organisms perform this decomposition?
Saprophytes, saprobionts, or decomposers.
How are ammonium compounds converted to nitrates?
Via nitrites by nitrifying bacteria.
How do plants absorb nitrates?
Through active transport into roots.
Why might scientists use μg (micrograms) to measure ammonia concentration?
Because ammonia is present in very small amounts in soil.
Why use μg instead of larger units?
To avoid many decimals, powers of 10, or standard form, making results easier to handle and graph.
Why is the unit expressed per gram (g⁻¹)?
To allow comparisons between different soil samples.
Name two biological molecules containing nitrogen removed during crop harvest.
Amino acids/proteins and nucleic acids (DNA, RNA).
Give examples of nitrogenous molecules other than proteins and nucleic acids.
ATP, ADP, NAD, NADP, cAMP, and chlorophyll.
Why do growing plants need phosphates?
To produce phospholipids for cell membranes.
