The Chemical Basis of Life

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The Chemical Basis of Life

• Chapter 4

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Matter

• Everything in the universe is made of matter
• Matter is anything that has volume or mass
• On Earth, matter exists in 3 states
• Solid
• Liquid
• Gas

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Elements and the Periodic Table

• An element is a substance that cannot be broken
  down into simpler substances by chemical or
  physical means
• There are at least 118 known elements, and new
  elements continue to be discovered
• At least 92 are naturally occurring, all of the
  others are produced in laboratories

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Periodic Table

• The elements have been organized by their
  properties in the periodic table
• The name of each element is represented by a
  symbol consisting of one, two or three letters
• Each element is also assigned an atomic number

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Periodic Table

• The rows in the periodic table are called periods
• Columns in the periodic table are called groups
• Elements within a group have similar properties

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Periodic Table

• Of the known elements, LIFE requires 25 chemical
  elements
• These elements combine in thousands of ways to
  form compounds

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Atoms

• All elements are made of atoms
• An atom is the smallest particle of matter that
  contains a characteristic of an element
• Parts of atoms
• Nucleus which is composed of protons neutrons
• Cloud of electrons orbiting around the nucleus

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Protons, Electrons Neutrons

• Protons
• Positively charged
• Number of protons atomic number
• Electrons
• Negatively charged
• Same number as protons
• Neutrons
• Neutral charge

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Electrons

• An electron is the smallest particle in an atom
• Electrons move in a cloud, divided into specific
  energy levels, around the nucleus of an atom

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Isotopes

• Atoms with the same number of protons but
  different numbers of neutrons are isotopes of an
  element
• Carbon-12 6 protons, 6 neutrons
• Carbon-14 6 protons, 8 neutrons
• Unstable element, radioactive

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Compounds

• A compound is a substance that consists of 2 or
  more elements that are chemically combined in
  specific portions
• Elements like to have filled energy orbitals and
  will bind with other elements to completely fill
  the orbitals

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Chemical Bonds

• Ionic bonds
• Bond between negative and positive ions
• Electron is transferred
• NaCl

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Chemical Bonds

• Covalent bonds
• Bond forms when atoms share electrons
• H2O

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Chemical Reactions

• Starting materials REACTANTS
• Ending materials PRODUCTS

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Practice!!

• Lets practice drawing out elements
• Bonding two elements together
• Balancing Equations

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Balancing Equations

• Unbalanced Equation
• C3H8 O2 ---gt H2O CO2
• There are 3 carbons on the left, but only 1 on
  the right.
• There are 8 hydrogens on the left but only 2 on
  the right.
• There are 2 oxygens on the left but 3 on the
  right.
• Balanced Equation
• C3H8 5O2 ---gt 4H2O 3CO2

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More Rules to Balance Equations

• We alter the co-efficients in the equation.
• Do NOT touch the subscripts for the atoms in a
  chemical species, or you will change it into an
  different chemical.
• That would be a bit like saying I want six
  chicken legs for a meal, so I'll go get a
  six-legged chicken. As chickens have two legs,
  you will need three normal, two-legged, chickens,
  not a six-legged mutant monster, probably from
  outer space.

wackyanimals.org/animal/4-legged-chicken-150
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Unbalanced equationH2SO4 Fe ---gt Fe2(SO4)3
H2

• Balance the SO4 first (as it is a complex ion and
  it is in one chemical species on each side)
• 3H2SO4 Fe ---gt Fe2(SO4)3 H2
• Now balance the Fe
• 3H2SO4 2Fe ---gt Fe2(SO4)3 H2
• Finally, balance the hydrogen
• Balanced Equation
• 3H2SO4 2Fe ---gt Fe2(SO4)3 3H2

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Structure of Water

• Polar molecule
• Opposite ends have opposite charges
• Hydrogen Bonds
• Due to waters polarity
• WEAK bond between water molecules

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Waters Life Supporting Properties

• Adhesion Cohesion
• Temperature Moderation
• Low Density of Ice
• Waters Ability to Dissolve Other Substances

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Adhesion and Cohesion

• Adhesion
• Attraction between different types of molecules
• Cohesion
• Tendency of same molecules to stick together
• Pulls the molecules at the surface tightly
  together (Surface Tension)

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Temperature Moderation

• Thermal Energy
• TOTAL amount of energy associated with the random
  movement of atoms and molecules
• Temperature
• AVERAGE amount energy of random motion of
  particles in a substance
• Water moderates temperature by
• Hydrogen Bonds
• Heating (breaks bonds, smaller temp change)
• Cooling (makes bonds, smaller temp change)
• Coastal Regions
• Evaporation

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Low Density of Ice

• Density
• Amount of matter in a given space
• Why is it important that ice floats?

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Waters Ability to Dissolve Substances

• Solute
• Substance that is dissolved
• Solvent
• Substance doing the dissolving
• Solution
• Mixture of two or more substances
• Aqueous Solution
• Water is the solvent

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Acids, Bases, and pH

• Acids
• Donates H to a solution
• Bases
• Removes H from a solution
• Sodium Hydroxide (NaOH) does this by binding with
  H to make Na and H2O
• pH Scale
• Describes how acidic/basic a solution is
• 1 Acidic
• 14 Basic
• 7 Neutral

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pH Scale
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Buffers

• Substances that cause a solution to resist
  changes in pH
• Maintains a constant pH level
• Why is this important?
• Human Blood 7.4 pH
• Certain chemical reactions (excess CO2,
  medications, etc) cause excess H which would
  make blood pH levels more acidic

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Antacid Lab

• Antacids are substances that act as buffers in
  our digestive tracts
• Which antacid works the best at neutralizing
  acid??

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The Molecules of Life

• Chapter 5

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Concept 5.1

• Carbon is the main ingredient of organic
  molecules.
• Key Terms
• Organic molecule
• Inorganic molecule
• Hydrocarbon
• Functional group
• Hydrophilic
• Monomer
• Polymer

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Carbon Bonding

• Organic Compounds
• Any compound that has Carbon in it
• Inorganic Compounds
• Compound that does not contain Carbon (H2O, O2
  and NH3)
• Besides bonding with other carbon atoms, carbon
  may also bond with atoms of other elements.
• Hydrocarbons (C - H)
• In addition to hydrogen, two other atoms
  frequently found in organic molecules are oxygen
  and nitrogen.

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Carbon Skeletons

• Carbon likes to form bonds it can make up to 4
  bonds (single, double, rarely triple) with other
  elements

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Functional Groups

• A group of atoms within a molecule that interacts
  in predictable ways with other molecules

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Monomers Polymers

• Monomers
• Small, molecular units
• Polymers
• Chains of linked Monomers
• Straight, Branched, or Folded
• Biomolecules
• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids

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Dehydration Reaction

• Removes water, forming bonds

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Hydrolysis Reaction

• Adds water molecule

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Review Questions 5.1

1. What is an organic molecule? Inorganic molecule?
2. What is the relationship between monomers and
   polymers?
3. To build a polymer, what molecule must be
   released? What is this process called?
4. To break down a polymer, what molecule must be
   added? What is this called?

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Concept 5.2

• Carbohydrates provide fuel and building material.
• Key Terms
• Carbohydrate
• Monosaccharide
• Disaccharide
• Polysaccharide
• Starch
• Glycogen
• Cellulose

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Sugars

• Carbohydrates
• Organic compounds made of sugars used for energy
• Sugars contain the elements carbon, hydrogen, and
  oxygen in a ratio of
• 1 carbon2 hydrogen1 oxygen (C6H12O6)
• Most have a ring shape

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Monosaccharides

• Simple sugars containing one sugar unit
• Glucose, Fructose, and Galactose
• Sugar molecules are the main fuel supply for
  cellular work
• Cells break down glucose molecules and extract
  their stored energy

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Disaccharides

• Double Sugar
• Made from a dehydration reaction between two
  monosaccharides
• Sucrose
• Most common disaccharide
• Major carbohydrate found in plant sap, helps
  nourish all of the parts of the plant

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Polysaccharides

• Long chains of monosaccharides
• Complex Carbohydrates
• Serve as energy stockpiles
• Starches in plants
• Cellulose in plants Fiber
• Glycogen in animals

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Carbohydrates lt3 Water

• Almost all Carbs are HYDROPHILIC
• Monosaccharides Dissacharides dissolve easily
  in water
• Cellulose and some starches do not dissolve

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Review Questions 5.2

• What is a carbohydrate? Name the elements it
  contains and in what ratio.
• Differentiate between a monosaccharide, a
  disaccharide, and a polysaccharide. Give an
  example of each one.
• Compare and contrast starch, glycogen, and
  cellulose.

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Nucleic Acids macromolecules of Carbon,
Hydrogen, Nitrogen, Oxygen, and Phosphorus.
a). Polymers formed from individual monomers
known as nucleotides.
1. Made up of three basic parts 5-carbon
sugar, phosphate group, nitrogenous base
2. Nucleotides joined by covalent bonds to form
polynucleotides (nucleic acids)
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b). Nucleic acids store and transmit hereditary,
or genetic information (ie. DNA, RNA)
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Concept 5.3

• Lipids include fats and steroids.
• Key Terms
• Lipid
• Hydrophobic
• Fat
• Saturated fat
• Unsaturated fat
• Steroid
• Cholesterol

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Characteristics of Lipids

• HYDROPHOBIC
• Lipids Functions
• Boundary that surrounds and contains the aqueous
  (watery) contents of your cells.
• Circulate in your body as chemical signals to
  cells.
• Fats store energy in your body.

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Fats

• Consists of a glycerol attached to three fatty
  acids
• Room Temperature
• Some fats are solid (Lard, Butter)
• Oils are liquids
• In addition to storing energy for later use,
  fatty tissues cushion your organs and provide
  your body with insulation

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Fats

• Saturated
• Fatty acid chain contains single-bonded carbons,
  all other bonds are with hydrogen
• Lard and Butter
• Unsaturated
• Some of the carbons are double-bonded together,
  fewer hydrogens
• Fats in fruits, vegetables, and fish

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Steroids

• Lipid whose carbon skeleton
• forms four fused rings
• Hydrophobic, but they are very
• different from fats in structure
• and function.
• Some steroids circulate in your body as chemical
  signals.
• Cholesterol
• Found in the membranes that surround your cells
• Starting point to produce other steroids
• Bad reputation high levels are linked to
  increased risk for cardiovascular (heart and
  blood vessel) disease.

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Review Questions 5.3

• What are the functions of lipids?
• Describe the structure of fats and steriods.
• Differentiate between saturated and unsaturated
  fats.

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Concept 5.4

• Proteins perform most functions in cells.
• Key Terms
• Protein
• Amino acid
• Polypeptide
• Denaturation

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Functions of Proteins

• Monomer Amino acid
• Proteins Polymer of Amino acids
• Responsible for almost all of the day-to-day
  functioning of organisms.
• Form structures such as hair and fur, make up
  muscles, and provide long-term nutrient storage.
• Less-visible functions include proteins that
  circulate in the blood and defend the body from
  harmful microorganisms, and others that act as
  signals, conveying messages from one cell to
  another.
• Controlling the chemical reactions in a cell.

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Amino Acids

• Consists of a central carbon atom bonded to four
  partners
• Three of the central carbon's partners are the
  same in all amino acids.
• One partner is a hydrogen atom.
• Two others are a carboxyl group and an amino
  group
• Differences
• Side Group/"R-group"
• Responsible for the particular chemical
  properties of each amino acid
• Leucines R-Group is hydrophobic, Serines
  attracts water

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Building a Protein

• Polypeptide
• Amino acids linked together in a chain
• Different order of amino acids different
  polypeptide chain

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Protein Shape

• Every protein is twisted/coiled into a shape
• Yarn/Sweater
• Denaturation of a Protein
• An unfavorable change in pH, temperature, or
  other environmental factor can cause a protein to
  unravel and lose its shape
• When a protein loses its shape it loses the
  ability to function

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Review Questions 5.4

• Describe the structure of protein?
• What are the functions of protein?
• What is the structure of an amino acid?
• What do lipids all have in common?

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Concept 5.5

• Enzymes are proteins that speed up specific
  reactions in cells.
• Key Terms
• Activation energy
• Catalyst
• Enzyme
• Substrate
• Active site

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Enzymes and Activation Energy

• In order to start a chemical reaction you have to
  weaken the bonds in the reactants
• This start-up energy is called activation
  energy because it activates the reactants and
  triggers a chemical reaction
• Match activation energy for a Candle

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Enzymes act as Catalysts

• Catalysts speed up chemical reactions
• Enzymes act as catalysts by lowering the
  activation energy barrier
• Enzymes provide a way for reactions to occur at
  the cells normal temperature
• Each enzyme catalyzes a SPECIFIC kind of chemical
  reaction and can be turned on/off depending on
  whether they are needed or not

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Activation Energy Barrier
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How Enzymes Work

• The shape of an enzyme fits the shape of only
  particular reactant molecules
• Substrate the reactant acted on by the enzyme
• Active Site the part of the enzyme where the
  substrate fits

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Review Questions 5.5

• Whats an enzyme and its function?
• Whats activation energy and how do enzymes
  affect this?
• Describe the significance of an enzymes shape.

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Enzyme Advertisement Project

• Enzymes are used everyday in products around your
  house using the household product given to you
  by your instructor research the following
• Identify the enzyme
• Identify its substrate
• What are its chemical products?

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Enzyme Examples

• Baby Food Trypsin
• Baking Proteases, Fungal Alpha-Amylase
• Contact Lens Cleaner - Proteases
• Dairy Lactases, Lipases
• Detergents Amylases, Cellulases, Lipases
• Fruit Juice Cellulases, Pectinases
• Meat Tenderizers - Papain
• Paper Amylases, Cellulases, Ligninases,
  Xylanases
• Photography Proteases (ficin)
• Rubber - Catalases

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