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20 terms

Chapter 3 key terms

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autotrophs
organisms that use energy from sunlight or from chemical bonds in inorganic substances to make organic compounds
carbohydrates
compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body
cells
The basic unit of all living things
chemical energy
a form of potential energy that is stored in chemical bonds between atoms
consumers
an organism that obtains energy and nutrients by feeding on other organisms or their remains.
ecosystem
living and nonliving things in an environment, together with their interactions
first law of thermodynamics
energy is neither created nor destroyed, but may be converted from one form to another
molecules
The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms; a group of like or different atoms held together by chemical forces
photosynthesis
process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches
producers
An organism that can make its own food.
biogeochemical cycles
process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another
carbon cycle
The organic circulation of carbon from the atmosphere into organisms and back again.
cellular respiration
the process by which cells obtain energy from carbohydrates; atmospheric oxygen combines with glucose to form water and carbon dioxide
compound
a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight
deoxyribonucleic acid
(DNA) nucleic acid that contains the sugar deoxyribose
element energy
farther the last energy level is from the nucleus, the easier it is to remove the electrons
kinetic energy
energy of motion
net primary production
The amount of energy accumulated in plant biomass that is available to the consumers in an ecosystem
potential energy
Energy that is stored and held in readiness
second law of thermodynamics
States that with each successive energy transfer or transformation in a system, less energy is available to do work.