environmental threats
a natural, nonrenewable fuel, such as coal, oil, or gas, that is formed over a very long time in the geological past from the remains of living organisms
a fossil fuel
a molecule that is produced by living things
a biomolecule
an organism that obtains its energy from an abiotic source, such as sunlight or inorganic chemicals
what is an autotroph
a member of a diverse group of biomolecules that are hydrophobic and include fats, oils, waxes, and other molecules
a lipid
a bacterial action that results in the combination of atmospheric nitrogen with other elements, making nitrogen available for use by plants
nitrogen fixation
gases in the atmosphere that trap heat within the atmosphere
what are greenhouse gases
the process by which autotrophic organisms capture light energy to convert carbon dioxide and water into glucose and oxygen, thereby storing some of the captured energy in chemical bonds
what is photosynthesis
organisms such as bacteria and fungi that break down the remains of dead plants and animals without the need for internal digestion
what are decomposers
a biomolecule that is made of one or more amino acid polymers joined together by peptide bonds and then folded into a complex structure that performs a specific function
a protein
a biotic or an abiotic environmental factor that restricts the growth of a population
limiting factor
the removal of a forest or stand of trees, which is then used for non-forest purposes
deforestation
the process by which cells convert chemical energy that is stored in various compounds, such as sugars, into useful energy for cellular processes; may be aerobic or anaerobic
cellular respiration
a relationship between organisms or species that is helpful to both
what is mutualism
the carrier of genetic information that is present in nearly all organisms; forms a double helix
DNA
the process by which bacteria convert organic nitrogen into inorganic ammonium
ammonification
the process of breaking down a substance into smaller components of organic matter; the process of decaying
what is decomposition
the sum of all the life on Earth
the biosphere
a starting substance, written on the left side of the chemical reaction arrow, that will be destroyed during a chemical change
what is a reactant
a monosaccharide sugar, C6H12O6, that is produced during photosynthesis and used during cellular respiration for energy production
glucose
the reduction of oxidized forms of nitrogen (nitrates), ultimately resulting in molecular nitrogen
denitrification
a reservoir, either natural or artificial, that absorbs more carbon than it releases
what is a carbon sink
pathways for the transport and transformation of matter within four categorical areas that make planet Earth (biosphere, hydrosphere, lithosphere, and atmosphere)
what are biogeochemical cycles
an ending substance, written on the right side of the chemical reaction arrow, that is created during a chemical change
what is a product
the process by which cells convert the chemical energy that is stored in nutrients into ATP, using an electron transport chain with a final electron acceptor other than oxygen
anaerobic
the biological transformation of ammonia or ammonium to nitrites and nitrates
nitrification