Chemistry of living organisms

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Chemistry of living organisms
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Matter

• Anything which has mass and takes up space
• Consists of elements
• Each element is mad of the same type of atom
• Each atom is a whole unit of matter and consists
  of subatomic particles

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Subatomic particles

• Each atom contains
• Protons
• Neutrons
• Electrons

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Protons

• Each has a mass of 1 AMU
• Each has a positive charge
• Protons are located in the nucleus of the atom
• The number of protons in an atom of an element
  identifies that element
• Carbon each carbon atom has 6 protons in its
  nucleus
• Nitrogen- each nitrogen atom has 7 protons in its
  nucleus
• Oxygen-

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Neutrons

• Located in the nucleus of each atom
• Has no charge
• Mass is the same as the proton
• The number of neutrons may be different for the
  same element
• Carbon can have 6, 7 or 8 neutrons, depending if
  it is C-12, C-13 or C-14
• used for dating organic matter

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Electrons

• Located outside of the nucleus
• Have no discernable mass (mass is 0)
• Have a negative charge
• Located in orbitals or shells orbiting around
  the nucleus
• Have an order of location where each energy level
  located further from the nucleus contains more
  energy

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Electrons

• Have an order of location where each energy level
  located further from the nucleus contains more
  energy
• Valence electrons are responsible for the
  chemical reactivity of an atom
• Neon is inert
• Fluorine is very reactive

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Order of electrons

• First level may not have more than two
• Second level may not have more than eight
• Third level may hold more than that but if it is
  the outer level it cannot have more than eight

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Diagram of subatomic particles
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Radioisotopes

• Emit radiation (energy)
• Uses include medical diagnosis, medical
  treatment, nuclear power for the generation of
  electricity

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Molecules

• Formed when atoms combine
• Energy is needed to join elements together
• These compounds now contain potential energy
• Example Food we eat, gets broken down to
  generate our energy (releases energy)
• Potential energy is stored in electron levels of
  the atom

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Types of Bonds

• An Ionic bond is formed when two atoms combine by
  giving/taking (losing or gaining) electrons.
  This gives stability to the molecule formed
• Example
• Sodium is a very reactive metal and very unstable
  in air
• Chlorine is a deadly gas to breathe
• When sodium forms a bond with chlorine, salt is
  formed which is not only a very stable compound
  but one that we use (too much of)

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Covalent bonds

• Do not give/take electrons
• Share their valence electrons
• Form the strongest of bonds WHY?
• Found typically in carbon/hydrogen containing
  compounds

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Hydrogen bonds

• The weakest of the bonds
• Formed between molecules and not between elements
  of a molecule
• Example hydrogen bonds are found in DNA and
  proteins which are very important molecules of
  life

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Water

• Is a polar molecule
• Life as we know it depends on water (every living
  thing needs it)
• Absorbs and holds heat efficiently
• Regulates our body temperature
• Universal solvent of living things

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The pH scale

• Gives us the hydrogen ion concentration of a
  solution
• Based on a scale of 0 14
• The pH lower than 7 indicates a high H
  concentration (acid)
• A higher than pH 7 indicates a low H (base)
• pH 7 is neutral and indicates equal H and OH

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pH

• Buffers are used to stabilize the pH
• Our blood must maintain a pH of 7.4
• Slightly _________
• It uses H2CO3
• Different locations in our body have different pH
  values
• Stomach
• Mouth

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Organic molecules

• Must contain carbon and hydrogen
• Found in all living things
• Fall into four major groups
• Carbohydrates
• Lipids
• Proteins
• Nucleic acids

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Carbohydrates

• Main functions include energy and support
• Monomers (single units) of this group include
  monosaccharides such as glucose
• Polymers include starch of plants and animals
  (glycogen)
• We digest polymers into monomers
• An IV solution administered into our veins is
  glucose, a monomer

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Proteins

• Main function is for building, repair
• Enzymes are made of protein
• Shape of protein is integral to its function
• The primary structure of a protein is governed by
  the order of amino acids
• The secondary structure is dependent on hydrogen
  bonding
• The tertiary structure (its 3 D form) is
  dependent on multiple types of bonds

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Enzymes

• Serve as catalysts in chemical reactions
• Are not used up in a reaction but serve as
  facilitators
• Example salivary amylase in saliva which begins
  the digestion of starches in your mouth
• In many instances ends in ase

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Lipids

• Contain the most energy (calories) per gram
• Are very large molecules
• Are not water soluble
• Include fats, triglycerides, sterols and waxes
• Becomes long term energy storage when calorie
  consumption exceeds caloric need

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Saturated v Unsaturated Fats

• Saturated fats
• Bad!
• Usually solid at room temperature
• Each C atom is surrounded by H atoms
• Animal fat including butter, whole milk
• Unsaturated fats
• Good!
• Usually liquid at room temperature
• Have double or triple bonds (less H atoms)

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Saturated v unsaturated

• Include olive oil, canola oil and oil found in
  nuts, fruits such as avocado
• Consumption of saturated fat raises bad
  cholesterol levels (LDL)
• Consumption of unsaturated fat raises good
  cholesterol levels (HDL)
• Consumption of trans-fats (hydrogenated fats to
  make the compound more compatible with product)
  are bad and being phased out of food products

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Nucleic acids

• Either DNA or RNA
• DNA is the molecule which contains the
  instructions or pattern of each organism
• Found in the nucleus of all eukaryotic cells
  (each cell which has a nucleus with the full
  number of chromosomes has the complete
  instructions for a new individual)
• Is a double helical molecule composed of monomer
  units called nucleotides
• Each nucleotide contains the sugar, deoxyribose,
  phosphate and a nitrogen base (either A,T, C or G)

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• RNA is found as tRNA, mRNA or rRNA
• Functions in carrying out DNAs instructions for
  the synthesis of proteins
• Is a single strand
• Made up of monomer units called nucleotides (just
  like DNA)
• The nucleotides have the sugar, ribose, a
  phosphate group and a nitrogen base (A, U, C, or
  G)

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