Chemical Building Blocks and Environmental Science: From Atoms to Earth's Systems, Slides of Environmental Science

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Earth’s Physical Systems: Matter,

Energy, and Geology

Chapter 2

Environmental Science

Bioremediation of the Exxon Valdez Oil Spill

• In 1989, 11 million gallons

coated the Alaskan

coastline

• defiled the pristine environment
• tourism plummeted and jobs were lost
• Bioremediation =
• pollution cleanup through enhanced natural biodegradation

Chemical building blocks

• Element = a fundamental type of matter, with a

given set of properties

• atoms = the smallest components that maintain an element’s chemical properties
• atom’s nucleus has…
  • protons (positively charged particles)
  • neutrons (no electric charge)
• Atomic number = number of protons
• Electrons = negatively charged particles surrounding the nucleus - allows formation of bonds

The structure of an atom

Radioactive decay

• Half-life =
  • the amount of time it takes for one-half of the atoms to give off radiation and decay
  • different radioactive isotopes have different half-lives
  • ranging from fractions of a second to billions of years
    • Uranium-235 (U 235 ), used in commercial nuclear power, 700 million years
    • P 32 – 14.29 days
    • S^35 – 87.2 days
    • C^14 – 5730 years

Molecules & Compounds

• Molecules = combinations of two or more atoms
  • oxygen gas = O 2
• Compounds = A molecule composed of atoms of

two or more different elements

• water = two hydrogen atoms bonded to one oxygen atom: H 2 0
• carbon dioxide = one carbon atom with two oxygen atoms: CO (^2)

Water: the main reason life can exist

• Hydrogen bond = oxygen

from one water molecule

attracts hydrogen atoms of

another

• Water’s strong cohesion

allows nutrients and waste

to be transported

• Water absorbs heat with

only small changes in its

temperature

• stabilizes systems

Additional properties of water

• Less dense ice floats on liquid water
  • Water dissolves other molecules

Organic Compounds

• Organic Compounds = carbon atoms joined by

covalent bonds and may include other elements

• such as nitrogen, oxygen, sulfur, and phosphorus
• Hydrocarbons = contain only carbon and hydrogen
• simplest hydrocarbon is methane
• hydrocarbons can be a gas, liquid or solid

Macromolecules

• Polymers = long chains of repeated molecules
  • the building blocks of life
• Macromolecules = large-size molecules
  • 3 types of polymers are essential to life
    • proteins
    • nucleic acids
    • carbohydrates
  • Lipids (are not polymers, but very essential)

A special process involving proteins

• Deoxyribonucleic acid (DNA) and Ribonucleic Acid (RNA): carry the hereditary information of organisms - long chains of nucleotides that contain - sugar, phosphate, and a nitrogen base
• Information in DNA is rewritten to RNA
• RNA directs amino acid assembly into proteins
• Genes = regions of DNA that code for

proteins that perform certain functions

• Genome = an organism’s genes
  • divided into chromosomes

Carbohydrates and lipids

• Carbohydrates = consist of atoms of carbon,

hydrogen, and oxygen

• sugars = simple carbohydrates
  • glucose = provides energy for cells
• complex carbohydrates build structures and store energy
  • starch = a complex carbohydrate
• Lipids = a chemically diverse group of compounds

grouped together because they don’t dissolve in

water

• for energy, cell membranes, structural support, and steroids

Organization of matter in living things

• Cell =

the basic unit of life’s organization

• Eukaryotes =

multi-celled organisms containing internal structures ( organelles )

• mitochondria, nucleus, golgi apparatus, etc.
• plants, animals, fungi, protists
• Prokaryotes =

single-celled organisms lacking organelles and a nucleus

Energy fundamentals

• Energy = that which can change the position, physical composition or temperature of matter - Potential energy = energy of position - Kinetic energy = energy of motion - Chemical energy = potential energy held in the bonds between atoms
• Potential energy is changed into kinetic energy to produce motion, action, and heat