A&P CH 2: Chemical level of organization

Matter

substance of universe (occupies space and mass)

Element

• cannot be broken down; pure substance

• all elements in body come from outside

what percent of elements makes up the human body?

95% is made up of:

• oxygen

• Carbon

• nitrogen

• hydrogen

Atom

• smallest quantity of element that retains its elements’ unique property

• protons, electrons

• neutrons

Proton:

• p⁺ ; positively charged

• “attract” electrons

• DETERMINES element (atomic number)

• protons + neutrons = atomic mass

• protons and electrons (should) equal

Electron:

• negative charge; like stability

• protons and electrons (should) equal

• located in valence shell

Neutron

• neutral charge

• protons + neutrons = atomic mass

Isotopes

• caried number of neutrons; hydrogen most abundant isotope

• unusual isotopes can be radioactive

• isotopes release its extra neutrons

• Can be used in medicine

Ions

• atom that differ in protons and electrons; not neutral (has charge)

• Cations (+) & anions (-)

Cations

• more protons than electrons

• positively charged

• an ion is a cation if it wants to donate electron (K⁺)

Anion

• fewer protons than electrons

• negatively charged

• an ion is a anion if it wants to gain electron (F^-)

Tell me about water

• universal solvent

• polar; can diffuse freely across cell membrane

• can dissociate ionic bonds

• 70% of bodyweight; lubricant/cushion

• “heat sink” (transfers heat around body)

Oxidation:

• Loss of electrons

• Ex: sodium is oxidized (Na⁺)

Reduction:

• gain of electrons

• Ex: chlorine is reduced (Cl^-)

Molecule:

• stable (ish) group of 2 or more atoms held together by chemical bond

Ionic bonds:

• ongoing close association between ions of opposite charge

• Ex: Na⁺ + Cl^- = NaCl

Hydrogen bond

• slightly positive hydrogen attracted to slightly negative hydrogen aspect of another molecule

• weak; dotted line

Covalent bond:

• 2 atoms share electrons to fill valence shell for stability

  • To satisfy octet rule; deals w/ electronegativity

• stronger than ionic

  • Has Polar and non polar covalent bond

Chemical reactions happen…

• during breaking or creation of bonds

Chemical reactions are influenced by…

• Heat (catalyst)

• temperature

• molecule size

• concentration of reactants

• products

Chemical Reactions

• Decomposition: AB —→A+B

• Synthesis: A+B—→AB

• Exchange (/switch_): AB ←→A+B (bonds are both formed and broken, then rearranged)

Activation Energy:

• activates reaction

Exergonic Reaction:

• produce more energy than they use

Endergonic Reaction:

• consume more energy than they produce

Products:

• materials going into a reaction

Reactants:

materials coming out of a reacction

Enzymes:

• proteins that lower amount of Activation Energy

Inorganic molecules include:

• waters, salts, acids/bases

• dissolved in water

• NOT based in Carbon or hydrogen

Colloid & suspension:

• mixture that’s like heavy solution (opaque shit)

• colloid but settles out

• Inorganic

Dehydration Synthesis:

• Creates water; takes OH & H

• 2 monomers are covalently bonded in a reaction in which one gives up a hydroxyl group & the other a H atom

• Molecule of water is released as byproduct

• Inorganic

Hydrolysis

• breaks down using water

• adds OH & H

• Covalent bond split

• Inorganic

Salt:

• Inorganic

• dissociate in water into cations/anions, NOT molecules

• Ions/salt form ionic bonds

  • Electrolytes: conduct currents

    • Create nerve impulses & muscle contractions

Acids:

• Inorganic

• dissolve to release a Hydrogen ion

• Strong acids:

  • releases ALL H⁺ to solution

• Weak acids:

  • don’t ionize completely (vinegar)

• In aqueous solutions:

  • dissociates into H⁺ anions

Bases:

• dissolve to release a hydroxide ion (OH^-)

• Inorganic

• Strong:

  • release ALL OH^- into solution or large amounts of H⁺ to make water

• Weak:

  • don’t ionize completely or take small amounts of H⁺ to make water

• In aqueous solutions:

  • dissociates into hydroxyl ions (OH^-) & cations

Buffer:

• solution of weak acid & its conjugate base

• can shift back and forth to absorb small amounts of acids/bases

• Inorganic

Functional group:

• group of atoms bonded together strongly that they tend to act as 1 unit

• Ex: Hydroxyls, methyls, phosphates

Organic molecules based on carbon (macromolecules)

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

• High energy compounds

Carbohydrates:

• Organic molecule; carbon based

• characterized by number of monomers (single units)

Monosaccharides:

• 1 simple sugar (1 carbon-based ring each)

• Ex: glucose, fructose

Disaccharides:

• 2 simple sugars condensed by dehydration synthesis

• Ex: sucrose, lactose

Polysaccharides:

• chains of simple sugars

• Ex: glycogen, starches