Chapter 2: Chemical Aspects of Life BSC 1008

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Chapter 2Chemical Aspects of LifeBSC 1008

• Instructor Jeff Laborda

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Atoms and Elements

• Chemistry Is the science of the structure and
  interactions of matter
• All matter is composed of chemical elements
• 112 elements
• 26 are found in the human body

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Atoms and Elements

• Of those 26 human body elements
• OCHN 96.2 of the human body
• O (oxygen) 65 ? Why so much???
• C (carbon) 18.5
• H (hydrogen) 9.5
• N (nitrogen) 3.2

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Atoms and Elements

• Each element is represented by a chemical
  (atomic) symbol ? see a Periodic Table O
  C H N Ca P K S Na Cl Mg
• Atoms are the smallest units of an element that
  still retain the chemical and physical properties
  of that element.

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What is the structure of an atom?

• Two parts to an atom
• Nucleus
• Protons positive charge
• Neutrons neutral (no) charge
• Electron Shells
• Electrons negative charge

protons electrons Neutral or No electrical
charge
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What is the structure of an atom?
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Isotopes

• An isotope is an atom of an element with a
  different number of neutrons. (same number of
  protons electrons)
• Carbon has three ? 12C, 13C, 14C
• Radioisotopes emit radiation, which can be useful
  in clinical settings.

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Molecules and Compounds

• Molecules are composed of two or more atoms
  bonding together through the interactions of
  their valence shell electrons.
• Molecules can have similar atoms bonding together
  ? O2
• Molecules can have dissimilar atoms bonding
  together ? H20
• Compounds are composed of two or more elements
  bonding together through the interactions of
  their valence shell electrons.

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Chemical Formulas

• Chemical formulas express the composition of a
  molecule.
• Examples H2O, C6H12O6, NaCl

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Chemical Bonds

• Chemical bonds are what hold a molecule together.
• There are three general types of bonds
• Ionic bonds
• Covalent bonds
• Hydrogen bonds

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Ionic Bonds

• Give up or receive an electron
• Resulting opposite charges between the atoms form
  the bond

Cation
Anion
Na
Cl-
Na
Cl-
Table Salt!
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Ionic Bonds
In the body, most ionic compounds dissolve in the
bodys waterwe call these dissolved ionic
compounds electrolytes.because they can
conduct an electrical current. Composition and
concentration of electrolytes are very important.

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Covalent Bonds

• Bond occurs by the sharing of electrons
• Non-polar vs. polar covalent bonds

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Hydrogen Bonds

• Attraction of partial and between molecules
• Used to link
  molecules or
  parts of large
  
  molecules
  together.

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Compounds Composing the Body

• Two main types of molecules (compounds) in the
  body
• Inorganic molecules (compounds)
• Examples water, acids, bases
• Organic molecules (compounds)
• Examples proteins, carbohydrates, lipids,
  nucleic acids, ATP

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Water (inorganic)

• Water is an inorganic molecule with special
  properties!!!
• Remember ? Water is a polar covalent molecule
  with hydrogen bonds.

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Water (inorganic)

• Water is an excellent solvent, dissolving both
  polar molecules (i.e., sugar) and ionic compounds
  (i.e., salt).
• Hydrophilic vs.
  Hydrophobic

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Water (inorganic)

• Water participates in chemical reactions
• Water has thermal properties it absorbs and
  releases large amounts of heat.
• Water serves as a lubricant.

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Water (inorganic)

• Review of waters valuable properties
• Serves as a solvent
• Participates in chemical reactions
• Has thermal properties
• Serves as a lubricant

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Water compartments within the body

• Intracellular fluid
• Extracellular fluid (interstitial fluid)
• Examples blood plasma, lymph, cerebrospinal fluid

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Acids and Bases (inorganic)

• Acid-Base balance is vital to maintaining
  homeostasis!
• The pH scale is what we use to measure acid-base
  balance!
• See Figure 2.5 on page 31

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Salts (inorganic)

• Salts are ionic compounds that dissociate (break
  apart) in water.
• This, for example, provides essential ions needed
  to carry electrical currents, especially in nerve
  and muscular tissues.
• Examples NaCl, KCl (see Table 2.5, p. 32)

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Carbohydrates (organic)

• Compose 2-3 of body mass
• Source of chemical energy
• Quick energy
• Short term energy storage
• Building blocks for other molecules
• Two types
• Simple
• Complex

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Carbohydrates (organic) Simple Sugars

• Monossacharides
• The simplest of carbohydrates
• Building blocks of all other carbs
• Source of energy for ATP production
• Glucose C6H12O6
• Glucose, fructose, and galactose are all common
  in foods
• Composes part of the DNA RNA molecule

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Carbohydrates (organic) Simple Sugars

• Diassacharides
• Two monossacharides a diassacharide
• The common ones in food
• Glucose Glucose Maltose (malt sugar)
• Glucose Fructose Sucrose (table sugar)
• Glucose Galactose Lactose (milk sugar)

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Complex Carbohydrates (organic) - Polysacchrides

• Three main types
• Glycogen storage form of carbs in the body
  reserve energy supply to be converted into
  glucose
• Starch storage form of carbs in plants
• Cellulose found in plantscannot be digested by
  humansbut does act as bulk to help pass feces

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Lipids (organic)

• Function depends on type of lipid
• Cushioning
• Insulation
• Water proofing
• Long-term energy storage
• Etc

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Lipids (organic)

• Triglycerides or Fats Hydrophobic!!! (less
  polar than carbs)
• Are the most concentrated energy source
• Are typically stored in the fat cells of the body
  primarily around internal organs
• Saturated fats filled by H atoms so that only
  single bonds between C C
• Saturated fats hydrogenated fats
• Solid at room temperature
• Ex butter, lard, and margarine
• Animal fats

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Lipids (organic)

• Triglycerides or Fats Hydrophobic!!! (cont)
• Are the most concentrated energy source
• Are typically stored in the fat cells of the body
  primarily around internal organs
• Unsaturated fats not filled by H atoms so that
  some C bonds are double bonds C C
• Monounsaturated vs. polyunsaturated
• Oils at room temperature
• Plant fats (e.g., olive oil, corn oil)

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Lipids (organic)

• Phospholipids Hydrophilic!!! (polar)
• Major components of cell membranes

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Lipids (organic)

• Steroids
• Examples
• Cholesterol an essential component of body
  cells building block of other steroids
• Sex hormones (e.g., testosterone, estrogens)
• Vitamins A, D, E, and K

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Proteins (organic)

• Large molecules with amino acids as their
  building blocks and peptide bonds
• There are 20 different kinds of amino acids
• Two amino acids bonded together form a
  dipeptide.
• A chain up to 50 AA polypeptide
• A chain of 50 2,000 form a protein molecule
• As a result of the way the different amino acids
  bondeach protein has a unique shape

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Proteins (organic)

• Shape Determines Function
• Structural elastin (connective tissues),
  keratin (fingernails, hair, skin), collagen
  (bone, connective tissue)
• Functional
• Regulatory hormones, neurotransmitters
• Contractile actin, myosin in muscle
• Immunological antibodies (fight pathogens),
  interleukins (stimulate WBC formation)
• Transport hemoglobin (O2 CO2 carrier),
  transporter proteins

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Organic CompoundsProteins

• Enzymes
• Proteins that facilitate chemical reactions
  within cells
• Are highly specific as to the substrate with
  which they react over 1,000 known enzymes in
  body lock key shape
• Are very efficient 100 million to 10 billion
  times faster reaction rates than without enzymes
• Under a variety of cellular controls by dictate
  of Genes
• Denaturation 3-diminsional shape determined by
  hydrogen bondswhich are easily broken by i.e.,
  hteat, pH change, toxins, radiation.

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Organic CompoundsNucleic Acids

• Huge organic molecules consisting of building
  blocks called nucleotides
• Contain C, H, O, N, and P
• Store and transmit genetic information
• Determine the order in which amino acids combine
  to form proteins
• DNA, RNA

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Organic CompoundsAdenosine Triphosphate (ATP)

• Energy currency of the body
• Supplies energy for
• Muscle contraction
• Cell division
• Molecular transport
• Synthesis reactions
• Etc
• Cellular Respiration
• Sugar Oxygen ADP P ? Carbon dioxide Water
  ATP

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• Chapter 2 Study Guide page 405
• Remember, answers are on my website!