Chemistry of Living Systems

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Chemistry of Living Systems
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Chemistry of Atoms

• Atom smallest unit of matter
• Three components of an atom are
• Electrons -1
• Protons 1
• Neutrons 0

Found outside the nucleus
Found in the nucleus
Found in the nucleus
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Count the electrons!

• of electrons in the outer shell are clues!
• Greater than 4 in the outer shell will take from
  other atoms
• Less than 4 in the outer shell will give to other
  atoms
• Provides hints on how and what types of bonds form

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Elements Essential to Life

• About 25 elements are essential to living
  organisms
• CHNOPS Make up 97 of living matter

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Natural Elements in the Human Body
ELEMENTS ATOMIC in HUMANS
Oxygen (O) 8 65.0
Carbon (C) 6 18.5
Hydrogen (H) 1 9.5
Nitrogen (N) 7 3.3
Calcium (Ca) 20 1.5
Phosphorus (P) 15 1.0
Potassium (K) 19 0.4
Sulfur (S) 16 0.3
Sodium (Na) 11 0.2
Magnesium (Mg) 12 0.2
Chlorine (Cl) 17 0.1
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Chemical Bonds

• Chemical Bonds are the attractive force that hold
  atoms together in a molecule
• Bonds form when electrons are shared OR
  transferred between atoms
• Covalent bonds sharing electrons (co- means
  to share as in cooperate)
• Ionic Bonds give and take electrons
• Hydrogen Bonds weak attractions between
  molecules
• Stronger atoms try to steal the Hs electron,
  but it keeps a tiny hold on it.

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Nonpolar Covalent Bonds

• Electrons are shared equally

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Polar Covalent Bonds

• Share electrons as in other covalent bonds, but
  the nucleus of one atom attracts the electrons
  more strongly so it is not equal.

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Ionic Bonding

• One atom gets extra electron(s) (becomes a
  negative ion) and one gives extra electron(s)
  (becomes a positive ion) the two ions attract
  each other.

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CARBON

• Why is carbon so important in biological
  molecules?
• Carbon is easy to synthesize (break down and be
  used).
• Molecules with carbon are called ORGANIC
• Molecules without carbon are called INORGANIC

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What are the important molecules of life?
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• WATER

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The Structure of Water

• V shaped molecule
• Unequal sharing of electrons causes oxygen to
  have a slightly negative charge
• called a polar molecule

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Properties of Water

• Cohesion is the tendency of molecules of the same
  kind to stick to one another.
• Water has stronger cohesion than most liquids

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• Water molecules are also attracted to certain
  other molecules
• Attraction between unlike molecules is called
  adhesion

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• Cohesion pulls molecules at the surface tightly
  together, forming a film-like boundary
• This is surface tension

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Carbohydrates(C,H, and O molecules in a ratio of
121)

• Carbohydrates are an important energy source for
  cells.

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TYPES OF CARBOHYDRATES

• Monosaccharide simple sugars made of one sugar
  molecule. (ex. Glucose)

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TYPES OF CARBOHYDRATES

• Disaccharides (ex. Sucrose)
• 2 monosaccharides linked together

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TYPES OF CARBOHYDRATES

• Polysaccharides ex. Starch, Cellulose)
• More than two sugars linked together.

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Did you notice how the sugars all sound the same?

• They all end in -ose (-ose sugar)
• Ex. Sucrose, Glucose, Fructose, Lactose

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TYPES OF CARBOHYDRATES

• Simple Carbs mono and disaccahrides
• Complex carbs starches, polysaccharides

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LIPIDS

• Made up of two parts
• A head (it is hydrophillic)
• A tail made of a hydrocarbon chain (it is
  hydrophobic).
• This lets the lipids form bilayers creating
  waterproof barriers like in a cells membrane.

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LIPIDS

• Fatty acids, waxes, fats, steroids and oils are
  formed by lipids (all are insoluble in water)

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Proteins

• Molecules made up of one or more chains of amino
  acids. They are used for many functions

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Proteins are used for

• Structure they make collagen in skin and
  keratin in hair/nails/horn

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Proteins are used for

• Movement actin and myosin in muscle stimulate
  the muscle to move

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Proteins are used for

• Defense antibodies in bloodstream

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Proteins are used for

• Storage corn seeds are predominately made of
  protein

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Proteins are used for

• Signals growth hormones in your blood stream

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Proteins are used for

• Nucleic Acids (used in DNA or RNA) long chains
  of pieces called nucleotides. A nucleotide has 3
  parts
• 1. five carbon sugar (ribose or deoxyribose)
• 2. phosphate group
• 3. Nitrogen base (A,T,C or G)

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Proteins are used for

• Catalysis enzymes which speed up processes in
  the body

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So what is an Enzyme?

• An enzyme is used to speed things up or help
  break things down in your body.

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Words You Should Know

• Enzyme (E) protein catalyst
• Catalysts speed up reactions without being
  changed by the reaction
• Substrate (S) reactant(s) in the
  enzyme-catalyzed reaction
• Active site area of enzyme where substrate(s)
  bind(s)

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Enzymes

• Enzymes are proteins with a SPECIFIC SHAPE
• The active site is a part of the protein which
  recognizes and binds to the substrate
• Cofactors (e.g. Zn 2, Cu 2, B vitamins) some
  enzymes wont hook-up to a substrates without
  these

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Specificity

• Lock and Key Model says there is a perfect
  fit between active site and substrate
• Modified to Induced Fit Model - active site can
  expand or contract to fit the substrate shape
• The induced fit model allows for small
  differences (possibility of letting several
  different kinds of substrates hook up)

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How do enzymes speed up reactions?

• Enzymes lower the activation energy (EAamount of
  energy that reactant molecules require to start a
  reaction)

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Enzymes

• Are involved in every biochemical reaction and
  thereby control metabolism
• Are named according to the reaction that they
  facilitateExamples Sucrase breaks down sucrose
  into glucose and fructose
• DNA Polymerase helps build DNA polymers

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Did you notice that enzyme all sound the same?

• All enzymes end in -ase
• DNA Polymerase
• Sucrase

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Factors affecting enzyme activity

• 1. TEMPERATURE
• 2. Concentration of Enzyme
• 3. Concentration of Substrate
• 4. pH
• 5. Inhibitors

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Types of Inhibition

• Competitive inhibition - molecules bind to the
  active site and prevent the substrate from
  binding
• Non-competitive inhibition - molecules that bind
  to a site other than the active site but change
  the shape of the active site so that it cannot
  bind the substrate

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Enzymes in Biotechnology

• How does pectinase work?

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• Pectin is the cement that holds plant cells
  together. Pectinase helps farmers break down the
  plant cells faster. For example it might help a
  farmer release the juice from apples faster to
  make lots of Apple Juice.

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Other enzymes in biotechnology

• Biological washing powder
• Meat tenderizer
• Production of glucose syrup