The Chemistry of Life

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• Chapter 6
• The Chemistry of Life

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• What do we already know about chemistry?
• How are chemistry and biology related?
• How does the study of chemistry relate to chapter
  1?

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• Section 1 - Atoms, Elements and Compounds
• both LIVING and NONLIVING THINGS
• are composed of CHEMICALS
• (chemical elements)
• LIVING THINGS are built from chemicals.

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• The functions of living things are
• a result of chemical reactions
• occurring within them.
• such as....
• digestion,
• respiration,
• movement,
• thinking,
• protein synthesis,
• circulation,
• excretion,.

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• Chemistry is the study of matter and the
  changes/transformations it undergoes
• Biochemistry is the study of
• the chemistry of living things

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Matter is anything that has mass and takes up
space

• What are some examples of matter?
• These are not matter.sound waves, radio waves,
  light waves, magnetism, gravity,
• Why? Because they do not take up space
• and they have no mass

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• ALL MATTER CAN BE CLASSIFIED AS A
• PURE SUBSTANCE proportions cannot vary
• elements H, C, O, and compounds H2O,
  C6H12O6,
• OR A
• MIXTURE proportions can vary
• - blood, salt water, urine, soil, air,.
• - can contain pure substances

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• MATTER
• 
  is composed of
  ATOMS
• having 3 subatomic particles
• protons, neutrons, electrons

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• protons - positive, nucleus
• determine the identity of the
  atom
• neutrons - neutral, nucleus
• electrons - negative,
• outside nucleus in energy
  levels

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(protons and neutrons)
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What is an ion?

• A charged atom (- or )
• it has either gained or lost an electron

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• atoms of 1 kind make up a
  
• (chemical) ELEMENT
• more than 110 different kinds
• about 90 are naturally occurring
• about 15 are man-made
• about 30 are found in living things
• C,H,O,N,P,S make up the bulk of living things

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• (chemical) ELEMENTS are arranged into a periodic
  table
• each element has a periodic chart entry..
• - (chemical) element symbol
• - atomic number number of protons
• - atomic mass number of protons and neutrons
  

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• ISOTOPES. atoms of an element having different
  numbers of neutrons
• Carbon 12 has. Carbon 13 has Carbon
  14 has
• 6 protons
• 6 electrons
• 6 neutrons

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• Radioactive Isotope (or Radioisotope)
• an isotope that is radioactive
• an atom having an unstable nucleus which will
  decay (lose energy) by emitting ionizing
  particles (ionizing radiation)
• Half-Life
• the time required for half the nuclei in a
• sample of a specific isotopic to undergo
  decay

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• elements chemically combine
• to form CHEMICAL COMPOUNDS

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• Would the following be organic or inorganic?
• MnO2
• NaOH
• C6H12O6
• NaCl
• CO2
• (NH4)3PO4
• C17H35COOH

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• Chemical Compounds are held together by.
• CHEMICAL BONDS
• Covalent Bond Ionic Bond
• sharing
  transfer
• of electrons of
  electrons

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Covalent Bond sharing of electrons
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Ionic Bond transfer of electrons
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Chemical Formula

• is written to represent a chemical compound
• is like a recipie
• Example the chemical formula for
• glucose is C6H12O6
• a chemical formula SHOWS. THE
  ELEMENTS
• AND HOW MANY ATOMS OF
  EACH

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Section 2 Chemical Reactions

• Chemical Reaction(s) . change in which atoms (or
  groups of atoms) are reorganized into one or more
  different substances
• involve the breaking of bonds
• and the
• formation of new bonds

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Chemical Equations

• is written to represent what occurs during a
  chemical reaction
• shows the reactants and products
• must be balanced
• Reactants elements or compounds that enter into
  a reaction
• Products elements or compounds that are
  produced by a reaction
• 2 NaOH 2 HCl 2 NaCl 2 H2O

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Chemical Equations

• LAW OF CONSERVATION OF MATTER . matter
  cannot be created or destroyed
• chemical equations must have the same number of
  atoms (of each element) on each side of the
  equation

2 NaOH 2 HCl 2 NaCl 2 H2O
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Activation Energy

• the minimum amount of energy
• needed to start a chemical reaction
• most reactions require some activation
  energy to get them started
• Endergonic Reactions absorb (require) energy in
  order to proceed -
• - cannot occur spontaneously
• Exergonic Reactions - release energy in the form
  of heat, light, or sound - can occur
  spontaneously

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Chemical Reactions and Enzymes

• Catalysts are chemical substances that
• lower the activation energy needed to
• start a chemical reaction
• ..therefore the reaction occurs faster

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enzymes..

• are biological catalysts
• are VERY specific (like a lock key)
• the activity of enzymes can be affected by ..
• pH and temperature
• enzymes
• are essential for life because many chemical
  reactions would occur too slowly to maintain life
  processes
• names usually end in ase

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Examples of enzyme names and their specificity

• Enzyme Lactase digests lactose (milk sugar)
• Enzyme Sucrase digests sucrose (table sugar)
• Enzyme Lipase digests lipids (fats)
• Enzyme Amylase begins digestion of amylose,
• a component of starch

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Enzyme Action.

• Substrate the substance (reactant) an enzyme
  reacts with
• Active Site site on the enzyme to which the
  substrates (reactants) bind
• Enzyme-Substrate Complex formed when an enzyme
  and substrates (reactants) bind together

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Section 3 Water and Solutions
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• WATER (H2O)
• chemical compound?
• organic or inorganic?
• contains the elements?

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• 2/3 of the human body is water
• blood is 92 water
• the brain is 75 water
• muscles are 75 water
• a person can live about a month without food, but
  only about a week without water

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WATER

• HAS UNIQUE PROPERTIES
• and is
• EXTREMELY IMPORTANT
• to living things

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• unique properties of water include
• polarity
• hydrogen bonding
• cohesion
• adhesion
• surface tension
• capillarity
• high heat capacity
• good solvent

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• POLARITY
• water is a polar covalent compound
• covalent because H and O share electrons
• polar because O atom is larger with a greater
  gravitational pull on the shared electrons

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• Therefore(because oxygen is larger)the shared
  electrons spend more time orbiting O.
• this gives O a slight negative charge.
• and H a slight positive charge
• Because of this water has an uneven
  distribution of charges (poles called polar)

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• POLARITY
• O shown in green
• has negative charge
• H shown in blue
• has positive charge

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• HYDROGEN BONDING
• forms between a.
• H atom of one molecule
• and
• an atom of another molecule
• a hydrogen (H) bond is a WEAK BOND (because it
  DOES NOT involve the electrons)
• H bonds allow water to cling to itself and to
  other substances with which it can form H bonds

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• COHESION an attractive force between particles
  of the same kind
• water likes water
• because it can form H bonds with itself

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Van der Waals forces(intermolecular forces)

• exist between MOLECULES of the same substance
• they are different from the forces that make up
  the molecule
• H bonding is a type
• of Van der Waals force

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• ADHESION an attractive force between particles
  of different kinds
• water likes (adheres to) other substances with
  which
• it can form H bonds

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Cohesion Adhesion

• Water is cohesive with itself
• Water is adhesive with the straw

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• SURFACE TENSION results from the
• cohesion of water molecules
• - this allows the surface of water to act
  like an elastic membrane

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• CAPILLARITY ability to move through narrow
  tubes and fine pores (often against gravity)

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• TEMPERATURE MODERATION
• water has a high heat capacity
• (or high specific heat)
• in other words, water is slow to
  heat and to cool it tends to maintain its
  temperature

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• Water regulates the Earth's temperature.
• Water regulates the
  temperature of
  the human body ( 98.6 degrees).
• Water also carries nutrients and oxygen to cells,
  cushions joints, protects organs and tissues, and
  removes wastes.

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• GOOD SOLVENT
• known as the universal solvent
• many substances are soluble (dissolve) in water
• many POLAR COMPOUNDS and IONIC COMPOUNDS are
  SOLUBLE (dissolve or dissociate) in water
• NONPOLAR COMPOUNDS are INSOLUBLE in water and are
  repelled by water

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• Water is not always pure
• it is often found as part of a mixture
• MIXTURE composed of 2 or more elements or
  compounds that are physically mixed together
• - proportions can vary

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• Homogeneous Mixture
• the components that make up the mixture are
  uniformly distributed
• Heterogeneous Mixture
• the components that make up the mixture are not
  uniform or have regions with different properties

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Mixtures can be

• Homogeneous uniform composition
• Heterogeneous components remain distinct
• 3 classes of mixtures
• solutions
• colloids
• suspensions

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• SOLUTION (a homogeneous mixture)
• solute (substance that is dissolved)
• solvent (substance in which another is
  dissolved)
• ex sweet tea, koolaid, saltwater

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Acids, Bases and pH

• water (H2O) can react to form ions
• chemists have devised a measurement system called
  the pH scale to indicate the concentration of
  H ions (pH) in a solution

water hydrogen
hydroxide ion ion
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Acids/Acidic Substances

• Release more H ions when dissociated
• Turn indicators red
• Taste sour
• Can cause burns
• Corrosive to eat away or erode
• pH less than 7

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Bases/Alkaline Substances

• Release more OH- ions when dissociated
• Turn indicators blue
• Taste bitter
• Can cause burns
• Corrosive to eat away or erode
• pH more than 7

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• pH scale is a measure of the potential H in a
  solution
• pH scale ranges from 0 to 14
• at a pH of 7 the concentration of H and OH- ions
  is equal
• pure water has a pH of 7
• acidic substances (0 to 6.9) have more H ions
  than OH-
• basic or alkaline substances (7.1 to 14) have
  more OH- ions

ACIDS
BASES
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• Each step on the pH scale represents a factor of
  10
• A substance with pH of 4 has 10 times as many
  H ions as a substance with a pH of 5
• What type of reaction occurs when acids bases
  are mixec? What are the products?

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Buffers

• The pH within living things (and in cells) must
  be kept fairly constant HOMEOSTASIS
• most cells within the human body need a pH
  between 6.5 and 7.5 if higher or lower, it will
  affect chemical reactions within the cells
• pH can be controlled with BUFFERS weak acids
  or bases that help to neutralize substances

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• Section 4 The Building Blocks of Life
  
• no other element comes close to carbons
  versatility
• there is a whole field of chemistry devoted
  to the study of carbon
  compounds.
• ORGANIC CHEMISTRY
• THE STUDY OF ORGANIC COMPOUNDS
• (contain C and H)

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• many of the organic compounds
• in living cells/living things.
• are
• POLY MERS made of many parts
• also known as
• MACRO MOLECULES large molecules

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• Polymers and Macromolecules.are made by joining
  smaller molecules called MONOMERS together
• monomer monomer monomer polymer or
  macromolecule

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There are 4 major groups of MACROMOLECULES that
are important to living things.

• CARBOHYDRATES
• LIPIDS
• NUCLEIC ACIDS
• PROTEINS

Because these macromolecules contain C H
they are also organic compounds
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CARBOHYDRATES
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CARBOHYDRATES.

• common examples.
• contain C, H, O usually in ratio of 121
• main function is to provide energy
• (the fuel for living things)
• some can also serve as.
• structural materials
• a form of energy storage

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• monomer (basic unit) of a carbohydrate.
• is the MONOSACCHARIDE (simple sugar)
• 3 common monosaccharides.
• glucose - produced by plants main fuel for LT
• galactose found in milk
• fructose found in fruit

LACTOSE which is also a sugar found in
milk is a DISACCHARIDE (made of 2
monosaccharides)
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• monosaccharides are joined together.
• to make a POLYSACCHARIDE (complex sugar)
• mono mono mono
  polysaccharide
• saccharide saccharide saccharide
• 3 common polysaccharides.
• glycogen animal starch stores excess carbs
• starch (or plant starch) stores excess carbs
  ex. potato
• cellulose plant fiber in cell wall

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LIPIDS
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LIPIDS

• common examples .
• insoluble (do not dissolve) in water
• contain C, H, O
• 3 common categories fats, oils, waxes
• main function is to store energy
• other functions include. waterproofing, chemical
  messengers, structural materials

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• monomer (basic unit) of a lipid is the FATTY ACID

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• 2 common categories of fats.
• SATURATED FATS
• animal products - usually solid at room temp.
• difficult for the body to break down
• UNSATURATED FATS
• plant products - usually liquid at room temp.
• easier for the body to break down

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NUCLEIC ACIDS
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NUCLEIC ACIDS

• contain C, H, O, N, P
• made of monomers (basic units) called nucleotides
• a nucleotide has 3 parts
• sugar
• nitrogen base
• phosphate group
• main function is to store and transmit genetic
  information in the form of a CODE
• examples include
• DNA and RNA

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PROTEINS
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PROTEINS

• common examples include.
• contain C, H, O, N
• made of monomers (basic units) called amino acids
  
• approximately 20 different kinds of amino acids
• amino acids can be put into any order, but their
  order is dictated by the information contained in
  DNA
• amino acids are bonded together by peptide bonds
• a chain of 100 amino acids is called a
  polypeptide

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PROTEINS

• are the most versatile of the 4 macromolecules
  and perform MANY VARIED FUNCTIONS .
• REGULATE CELL PROCESSES insulin, growth hormone
• BUILDING/STRUCTURAL MATERIALS for cells and
  tissues hair, muscles, skin, nails,
• TRANSPORT OF SUBSTANCES hemoglobin
• IMMUNITY- antibodies
• MARKERS TO ALLOW CELLS TO RECOGNIZE self from
  non-self and identify cell types
• CONTROL RATES OF CHEMICAL REACTIONS