PowerPoint Presentation to accompany Hole

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PowerPoint Presentation to
accompanyHoles Human Anatomy and
Physiology, 9/e
byShier, Butler, and Lewis
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Chapter Two

• Chemical Basis of Life

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Chemistry and Biochemistry

• Chemistry considers the composition of
  substances and how they change.
• The chemistry of living organisms is biological
  chemistry or biochemistry.
• Biochemistry has been important in explaining
  physiological processes and in improving medicine.

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Matter and Elements

• Matter is anything that has weight and takes up
  space.
• All matter is composed of elements.
• Elements exist is their pure form or in chemical
  combinations called compounds.
• Elements are composed of atoms.

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Atomic Structure

• Nucleus center of the atom, containing protons
  and neutrons
• Protons positively charged particles
• Neutrons particles which lack charge
• Electrons very small, negatively charged
  particles which encircle the nucleus

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Figure 2.1
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Isotopes

• Atomic number is the number of protons. It is
  the same for all atoms of an element.
• Atomic weight is the number of protons and
  neutrons.
• Atoms that have the same atomic number, but
  different atomic weights are isotopes.

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Stable and Radioactive Isotopes

• Isotopes that do not decompose are called stable
  isotopes.
• Isotopes that have unstable nuclei that decompose
  are called radioactive isotopes.
• Radioactive isotopes release energy or particles
  until they reach a stable form.

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Atomic Radiation

• Alpha radiation consists of particles from atomic
  nuclei, two protons and two neutrons. These
  particles are heavy, move slowly, and do not
  penetrate matter.

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Atomic Radiation

• Beta radiation consists of smaller electrons that
  travel fast and penetrate matter.
• Gamma radiation is similar to X-radiation and is
  the most penetrating of these forms.

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Molecules

• Two or more atoms combine to form a molecule.
• Molecules are distinctive from the elements of
  which they are composed.
• A molecular formula illustrates the number and
  type of atoms found in a molecule.

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Atomic Structure

• Atoms, such as Helium, whose outermost electron
  shells are filled, have stable structures and are
  chemically inactive or inert.
• Atoms with incompletely filled outer shells tend
  to gain or lose electrons in ways that empty or
  fill their outer shells and create a stable
  structure.

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Molecular Bonding

• Ions are formed when atoms gain or lose
  electrons.

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Molecular Bonding

• Ionic or electrovalent bonds are formed by the
  attraction of oppositely charged ions.

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Molecular Bonding

• Covalent bonds are formed by the sharing of
  electrons between atoms.

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Molecular Bonding

• Hydrogen bonds are weak bonds between polar
  molecules.

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Polar Molecules

• Covalent bonds can be formed where the electrons
  are not shared equally.
• This results in a polar molecule that has equal
  numbers of protons and electrons, but one atom
  has more that its share of electrons, becoming
  negative, and one atom has less, becoming
  positive.

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Polar Molecules

• These polar bonds occur where hydrogen bonds to
  oxygen or nitrogen.

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Chemical Reactions

• Synthesis Reaction A B AB
• Decomposition Reaction AB A B
• Exchange Reaction AB CD AD CB
• Reversible Reactions can proceed in either
  direction

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Reversible Reactions

• Many chemical reactions are reversible.
• The direction in which the reaction proceeds
  depends on many factors such as
• - the proportions of products
• - reactants
• - amount of energy
• - presence of catalysts
• - molecules that influence the rate of
  reaction, but are not consumed in the
  reaction.

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Acids, Bases, Salts

• Polarity of water causes dissociation of salts,
  releasing ions.

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Acids, Bases, Salts

• Electrolytes release ions in water.
• Acids release hydrogen ions (H).
• Bases release ions that combine with H.
• Salts are formed by the reaction between an acid
  and a base.

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Acid and Base Concentrations

• Hydrogen ions concentrations are measured in
  grams of ions per liter of solutions.
• The pH scale illustrates the hydrogen ions
  concentration in a convenient form.
• Pure water ionizes only slightly and results in
  equal numbers of hydrogen and hydroxyl ions, pH
  7, chemically neutral.

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Hydrogen Ion Concentration

• Solutions with more hydrogen ions than hydroxyl
  ions are acidic with ph values of less than 7.
• Solutions with more hydroxyl ions than hydrogen
  ions are basic with ph values of greater than 7.

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Body Fluid pH Changes

• Fluids in the human body function in a narrow ph
  range.
• Blood ph of 7.5 to 7.8 is alkalosis, resulting in
  agitation and dizziness.
• Blood ph of 7.0 to 7.3 is acidosis, resulting in
  disorientation and fatigue.

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Figure 2.9
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Inorganic Substances

• Water
• Oxygen
• Carbon Dioxide
• Inorganic Salts

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Water

• Water is the most abundant compound in living
  material.
• It makes of 2/3 of the weight of an adult human.

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Water

• Substances dissolve in water, making it possible
  for metabolic reactions to occur.
• Water aids in transport of substances.
• Water absorbs and transports heat.

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Oxygen and Carbon Dioxide

• Oxygen is used to release energy from nutrient
  molecules.
• Carbon dioxide is produced as a waste product
  when energy is released during certain metabolic
  reactions.

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Inorganic Salts

• Inorganic salts are the source of many important
  ions, including Na, Cl-, K, Ca, and many
  others.
• These play a role in metabolic reactions and must
  be maintained in appropriate concentrations.
• This is called electrolyte balance.

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Organic Substances

• Organic molecules are carbon based molecules
  containing hydrogen and often oxygen.
• Important groups of organic substances in cells
  include carbohydrates, lipids, proteins, nucleic
  acids.

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Carbohydrates

• Carbohydrates water-soluble molecules containing
  carbon, hydrogen, oxygen
• Sugars monosaccharides, disaccharides

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Carbohydrates

• Polysaccharides built of simple sugars starch,
  fiber, glycogen

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Lipids

• Three fatty acids combine with glycerol to form a
  triglyceride.

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Lipids

• Fatty acids can be saturated or unsaturated.
• Phospholipids contain two fatty acids and a
  phosphate group.

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Lipids

• Steroids are lipids composed of connected carbon
  rings, ex cholesterol.

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Saturated vs. Unsaturated Fats

• A diet rich in saturated fat increases a
  persons risk of atherosclerosis.
• It is healthful to substitute unsaturated fats.
  Saturated fats are found in fatty foods that are
  solid at room temperature.
• Unsaturated fats are found in foods that are
  liquid at room temperature.

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Proteins

• Wide range of functions
• Chain of amino acids of varying lengths
• Amino acids contain a central carbon, an amino
  group, a carboxyl group, and a side chain (R
  group)
• Amino acids are linked in a peptide bond joining
  the amino of one and carboxyl group of another
  amino acid

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Levels of Protein Structure

• Primary amino acid sequence
• Secondary coil or sheet formed by hydrogen bonds
  between the amino acids
• Tertiary three dimensional shape created by
  hydrogen and covalent bonds
• Quarternary association of several separate
  protein chains

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Figure 2.18
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Nucleic Acids

• RNA
• ribose
• single strand
• aid in protein synthesis

• DNA
• deoxyribose
• double stranded
• store genetic information

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Nucleic Acids

• Large, complex molecules
• Chains of nucleotides
• Nucleotides are composed of a sugar, a phosphate
  group, and one of five nitrogen bases

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Figure 2.20a
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Figure 2.20b