Cell Composition

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Cell Composition
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Botany 1010

• September 9, 1999
• Lecture 3

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Composition of Living Things

• All living things are composed of ?
• The smallest unit of living matter is ?
• The automatic tendency to maintain appropriate
  internal environment is called ?
• Four characteristics of living things are ?
• Biological growth occurs from the ?

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Biological growth occurs from the ?

• Cells reproduce from a blue print called DNA,
• Dioxy-ribo-nuclaeic Acid
• Asexual reproduction
• a copy of the blue print splits into 2
  individual
• Sexual reproduction
• two parents blue prints combine to form a new
  individual
• Metabolism is responsible for growth,
  maintenance, and reproduction

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Evolutionary Change

• Charles Darwin theorized that ?
• These changes were selected because they ?
• This Theory is referred to as ?
• And occurs at the _____ level within a _______ ?
• Various populations of different species (birds)
  that interact are communities

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Properties of _____ are

• Species
• ?
• ?
• ?
• ?
• ?

• Population
• ?
• ?
• ?
• ?

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Biological Organisms can be organizedbased on
differences in

• Chemical
• Cellular
• Multicullular
• Ecological
• Functional

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Taxonometry is ?

• K
• P
• C
• O
• F
• G
• gt S

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How many Kingdoms of Life ?What are they?An
organisms Scientific name is?
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Reasoning

• Using general principles or experience to infer
  more detailed predictions is ?
• Using specific examples to draw a general
  conclusion ?

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The scientific method?

• Is a process of critical review skepticism
• recognize a problem
• make observations
• developing an educated guess, a hypothesis
• test your guess through experimentation
• evaluate your results
• have results peer reviewed

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Guidelines for scientific thought

• hypothesis consistent with what is known
• hypothesis must be testable
• the test must be repeatable
• it must be falsifiable
• IF berries are blue,
• THEN they are blue berries
• IF berries are NOT blue,
• THEN they are NOT blue berries

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Be Skeptical, Be Objective

• Sources of ERROR
• BIAS
• ATYPICAL SAMPLE
• Probability of ERROR (r2)
• ACCURACY
• PRECISION
• Theory predictions made using the theory as a
  guide are consistently accurate and precise

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Chemistry of Life

• Atoms
• Molecules
• composed of atoms held together by ionic or
  covalent bonds

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ATOMS

• Composed of Protons, Neutrons, and Electrons
• Atomic Nucleus contains Protons and Neutrons
• Neutrons and Protons have similar mass (weight)
• Electrons have a very small mass
• and spin around the Atomic Nucleus
• Atoms have equal number of protons ()
• and electrons (-)

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Elements

• A substance that cannot be broken down into a
  simpler substance, and still maintains its
  characteristics
• 92 naturally occurring elements
• Latin / English names
• Denoted by a two letter chemical symbol
• Elements have a fixed number of protons
• This number is an elements Atomic Number

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Elements

• H
• O
• N
• C
• Na
• P

• Hydrogen
• Oxygen
• Nitrogen
• Carbon
• Sodium
• Phosphorous

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Atomic Numbera subscriptwritten to the left of
the Atomic Symbol

• 1H
• 8O
• 23/11 Na

• Hydrogen
• with 1 proton
• Oxygen
• with 8 protons
• Sodium
• 12 neutrons,
• 11 protons, and an
• atomic mass of 23 (1112)

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Molecules

• Two atoms combine to form a molecule
• 8O 8O O2
• Common notation
• O O O2, Oxygen Molecule
• Molecules and or Atoms combine in fixed ratios
  to form Compounds
• 2 H 1 O H2O, Water Molecule (compound)

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Chemical Bonds

• Covalent
• electrons are shared between atoms in a molecule
  or compound
• Single bond share one electron
• (hardest to break apart)
• Double bond share two electrons
• Triple bond share three electrons
• (easiest to break apart)

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Covalent Bonds

• Nonpolar Covalent bonds
• Atoms have equal attraction for electrons
• O2, each Oxygen shares electrons equally
• Polar Covalent bonds
• Atoms have different attraction (affinity) for
  shared electrons
• H2O, Hydrogen atoms are electro-positive (2-1)
• Oxygen atoms are electro-negative (1-2)

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Ionic Bonds

• Polar Electrons from one atom are transferred
  to another
• One atom gains an electron and becomes negatively
  charged (ANION)
• The other atom looses an electron, thus there are
  more protons than electrons in the atom, causing
  a positive charge (CATION)

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Ionic Compounds

• Cations and Anions are held together by their
  opposite charges (mutual attraction)
• Na (Sodium) donates electron (cation)
• (positive charge 1)
• Cl (Chlorine) receives electron (anion)
• (negative charge -1)
• NaCl, Ionic Compound called SALT

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Ionic Compounds

• It takes a great deal of energy to overcome the
  electrical attraction in solid substances that
  have ionic bonds
• Ionic bonds dissolve easily (split apart) in
  water, WHY?
• Hydrogen (charge) attracts anion (Cl-)
• Oxygen (-charge) attracts cation (Na)

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Water Chemical Properties

• Water is an excellent SOLVENT
• It easily dissolve ionic bonds
• Process is called HYDRATION
• Polar compounds are water loving Hydrophillic
• Non Polar compounds are water hating
• Hydrophobic (oil water dont mix)

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Water Properties

• Unique biological solvent
• Capable of dissolving other substances
• because it is polar, its electrons from one
  atom can be given to another atom/molec.
• It is Cohesive pulling other things with it
• It is Adhesive sticking to other surfaces
• Is Water important to biological processes ?
• your body 70 cells 80 of weight

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Water Properties

• Changes temperature more slowly than other
  substances
• Specific Heat temperature required to increase
  one gram of a substance one degree centigrade
• High Heat of Vaporation sweat cools us by
  getting rid of excess heat, evaporation
• Salts dissociate in water and conduct electrical
  current (nerve impulses, etc.) as electrolytes

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Water Properties

• Acids ionize in water to yield
• hydrogen ions and an anion, (negative charge
  -1)
• Bases dissociate in water to produce
• hydrogen ions and a cation, (positive charge
  1)
• The negative logarithm of the concentration of
  hydrogen ions are measured as pH
• pH of water is 7.0