3.3 nutrient cycles Flashcards
Nutrient Cycles
The movement and exchange of elements that are essential to life, from inorganic molecules, through fixation and then into living organisms, before being decomposed back into inorganic molecules
Nutrient
A chemical that provides what is needed for organisms to grow, repair damaged cells or tissues, release energy or for their metabolism
Assimilation
The conversion of a nutrient into a usable form that can be incorporated into the tissues of an organism
Primary Producers
Organisms that produce biomass from inorganic compounds; in almost all cases these are photosynthetically active organisms
Polymer
A large molecule made from many repeating sub-units
Monomer
The smallest unit of a polymer; monomers are able to join chemically to form longer molecules
Starch
A carbohydrate made from chains of glucose molecules joined together
Cellulose
An important component of plant cell walls which is made from many straight chains of glucose molecules held together by hydrogen bonds
Triglyceride
A type of lipid which is made from a glycerol molecule joined to three fatty acid chains
Fatty acid
Lipid molecules that are a major constituent of triglycerides and phospholipids
Hydrophobic
A molecule without a charge which repels water molecules
Residence Time
The average time that a particle spends in a particular system
Excretion
The process of eliminating the waste formed from the chemical reactions within living cells
Sink
An area where there is a net loss of material (for example, where more gas dissolves into the ocean than diffuses into the atmosphere)
Source
An area where there is a net gain of material (for example, where more gas diffuses into the atmosphere than dissolves into the ocean)
