Elements of Life

1
Elements of Life

• Chapter 2

2
Ecology

• The scientific study of relationships between
  organisms and their environment
• Every organism is a chemical factory that
  captures matter and energy from its environment
  and transforms them into structures and process
  that make life possible.

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3
Matter

• Everything that takes up space and has mass
• Solid, liquid, gas and plasma (4 states)
• Matter is neither created nor destroyed but
  rather recycled over and over again (Conservation
  of matter)
• If everything goes somewhere, where do the things
  we dispose of go after the garbage truck leaves?

4
Elements

• Substances that cannot be broken down into
  simpler forms by ordinary chemical reactions
• 115 known (92 natural)
• N, C, H, O 96 of the mass of most living
  organisms

http//www.corrosionsource.com/handbook/periodic/p
eriodic_table.gif
5
Atoms

• The smallest particles that exhibit the
  characteristics of the element
• Protons (), Neutrons, Electrons (-)
• Protons Neutrons Nucleus (Atomic Mass)
• Atomic Number number of protons
• Isotopes different number of neutrons within
  the same element (15N , 14N)
• Unstable isotopes may spontaneously emit
  electromagnetic energy, or subatomic particles,
  or both. (Radioactive waste, nuclear energy)

6
Compounds

• Joined atoms
• A pair of group of atoms that can exist as a
  single unit is known as a molecule
• Ionic bonds opposite charges attracting
  (NaCl-)
• Covalent bonds sharing of electrons (H2O) Polar
  molecules
• Oxidized atom gives up an electron (Oxidation
  reaction oxygen usually takes the electron)
• Reduced atom gains an electron (Reduction
  reaction)

7
Forming bonds requires Energy

• Activation energy energy needed to initiate the
  reaction
• Some energy is used to form the bonds, but the
  net result is a release of energy (heat)

http//fig.cox.miami.edu/cmallery/255/255enz/acti
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8
Electrical Charge

• Ions charged particles
• Negatively charged atoms anions ?Cl-
• Positively charge atoms cations ?Na
• Substances the readily give up hydrogen ion in
  water (Acids HCl ? H Cl-) pH lt 7
• Substances the readily bond with H ions (Bases
  NaOH ? Na OH-) pH gt 7

9
pH Scale

• pH 7 is neutral
• pH 6 represents ten times more hydrogen ions in
  solution than pH 7
• Buffers solutions that accept or release
  hydrogen ions.
• Alkaline rocks can buffer acidic precipitation

http//www.dreddyclinic.com/images/ph_scale.jpg
10
Water

• Polar molecule
• Only inorganic liquid that exists under normal
  conditions at temperatures suitable for life
• Cohesive (stick together) lets it exhibit
  capillary action
• Expands when it crystallizes
• High heat of vaporization (sweating is a good way
  to get rid of excess heat)
• High specific heat a lot of heat is absorbed
  before it changes states

11
Organic Compounds

• Chains and rings of carbon form the backbone of
  organic compounds
• Lipids (fats and oils) store energy for the
  cells, and they provide the core of cell
  membranes and other structures (hydrocarbons)

http//www.eccentrix.com/members/chempics/Slike/Li
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12
Organic Compounds

• Carbohydrates (sugars, starches, cellulose)
  store energy and provide structure to cells
  (glucose)

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Organic Compounds

• Proteins (amino acids) formed by chains of
  amino acids, provide structure for the cell and
  countless cell functions (enzymes, identify
  disease causing microbes, make muscles move,
  transport oxygen, regulate cell activity)

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14
Organic Compounds

• Nucleic acids (DNA and RNA) complex molecules
  made of a five-carbon sugar (ribose or
  deoxyribose), ore or more phosphate groups and an
  organic nitrogen-containing base called either a
  purine or pyrimidine

http//www.swbic.org/products/clipart/images/nacol
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15
Cells

• Fundamental units of life
• Minute compartments within which the processes of
  life are carried out
• Can contain organelles
• Enzymes molecular catalysts that regulate
  chemical reactions without being used up or
  inactivated in the process
• Metabolism the multitude of enzymatic reactions
  performed by an organism

http//training.seer.cancer.gov/module_anatomy/ima
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