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Chemistry Lecture
Microbiology 2
Question | Answer |
---|---|
What are the major elements of the body? | CHNOPS - Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur. |
What elements make up 95% of the human body by weight? | Oxygen, Nitrogen, Carbon and Hydrogen. |
Explain: Atomic Number vs. Atomic Mass | Atomic Number - makes an element unique; number of protons. Atomic Mass - number of protons and neutrons in an atomic nucleus. |
How are ions formed? | Ions are formed when atoms gain or lose electrons to stabilize their orbitals. (you can have several of the same elements with same atomic # but different # of electrons) |
What is a cation (and how is it made)? | Ion with a positive charge. Atom loses 1 or more electrons, leaving atom with positive charge. |
What is an anion (and how is it made)? | Ion with a negative Charge. Addition of electron leaves an atom with a negative charge. |
How many electrons does the first orbital hold? | 2 electrons |
How many electrons does the 2nd and 3rd orbital hold? | 8 electrons (and follows the octet rule) |
How does an atom become stable? | When orbitals are full, the atom becomes stable. |
What are molecules? | 2 or more atoms bound together. |
What are 2 types of molecules? (and what is the difference between the two?) | Organic vs. Inorganic: Organic molecules are carbon based and inorganic molecules are everything else. |
What are the major biological organic molecules? (4) | Proteins, lipids, carbohydrates, and nucleic acids. |
Is water TECHNICALLY organic or inorganic? | Inorganic because not carbon-based. But it is essential and used in organic chemistry. |
Where does polarity come from? | Results from uneven sharing of electrons between atoms in a molecule. |
What does polarity result in? | Results in partial charges. |
What is a critically important polar molecule? | Water |
Explain the polarity of water: | Electronegative oxygen creates partially negatively charged region, which is attracted to partially positive charged area of a H atom on a different molecule. |
The two hydrogen atoms (in water) bind to form a ____________________ bond and share 2 electrons to become ___________. | Covalent bond; to become stable (with the outermost orbital becoming full) |
The oxygen atoms take on two hydrogen atoms (in water) to fulfill what rule? | Fulfills octet rule; forms water. |
Nonpolar molecules result from what? | Nonpolar molecules result from equal or near equal sharing of electrons among atoms in a molecule . |
What is electronegativity? | The ability of a nucleus to attract electrons. (Unequal sharing of electrons causes polarity) |
What is the number of particles in a substance without its regard to mass or charge? | Molarity |
How is molarity measured? | Moles of solute / Liters of solution |
What is 1 mole equal to? | Avagadro's Number: 6.022x10^23 particles |
What are the 3 types of chemical bonding? | Covalent, Ionic, and Hydrogen |
Explain covalent bond: | Strong bond; sharing of electrons to fill/stabilize outer orbital. |
Explain ionic bond: | Weak bond; gain or loss of electron(s) to fill outer orbital. |
Explain hydrogen bond: | Weak bond; bond between polar hydrogen and nearby Oxygen, Nitrogen or Fluorine atom (NOF) |
What is a solution? | Solute dissolved in a solvent. |
Give an example, using water, of "Like dissolves Like" | Polar water dissolves other polar and charged particles. (Solutes dissolve in water; due to attractions of opposite charges to polarity of water) |
Water cannot easily dissolve what? | Lipids and other non-polar molecules (example: molecular oxygen and nitrogen) |
Because water cannot dissolve molecular oxygen, what do we need in our bodies? | Hemoglobin to carry molecular oxygen through aqueous blood. |
What is concentration? | Solute amount / Solvent amount |
What is meant by % solution? | Mass to volume ratio. (Percent of total solution occupied by the solute) |
How would a 5% Glucose solution be made? | 5 g glucose dissolved in 100mL of water. |
Assume 1 g = ? | 1g = 1mL (cm3) which is true for water |
Explain moles vs. equivalents: | Mole is the number of particles without regard to mass or charge. (1 mole = avogadro's number). Equivalent (Eq) is based on the number of particles and charge. Can be monovalent or divalent. (commonly used for ions in blood) |
What are monovalent ions? | 1 Eq per mole (sodium is monovalent because it only has one charge) |
What are divalent ions? | 2 Eq per mole (Mg2+ is divalent) |
Sodium and potassium are often expressed in what units? | mEq/L (Having to do with equivalents) |
What is a dipole? | Separation of Charge |
In body fluid, what is the solvent? | Water (polar and charged) |
What is the solute concentration in body fluid? | .89% NaCl solution (Normal Saline) |
What does isotonic mean? | Same concentration |
What does hypertonic mean? | Higher concentration |
What does hypotonic mean? | Lower Concentration |
What are acids? What are bases? | Acids = Hydrogen ion donors. Bases = Hydrogen ion acceptors. |
What is the pH scale? | ph = -log[H+] |
What is the relationship between pH and H+ concentration? | Inverse relationship: the lower the pH, the higher the Hydrogen Ion Concentration. |
A change of 1 in pH reflects what kind of change in H+ concentration? | A change of 1 in pH reflects a 10-fold change in H+ concentration. |
Explain the pH scale briefly: | pH Scale goes from 1-14; 7 is neutral. 1-6 is acidic, 8-14 is basic/alkaline. |
A scale that goes from pH 2.0 to pH 7.0 would have what amount of change in H+ concentration? | 10^5 fold change in H+ concentration |
Where in the body do you find a pH of 7? Where in the body do you find a pH of 2.0? | Intracellular pH = 7. Gastric Acid pH (in the stomach) = 2.0 |
What is a buffer? | Chemicals that minimize change of pH. |
HCl is good to use as a buffer for what type of situation? | HCl is not a super effective buffer, but it can be used to decrease acidity! HCl --> H+ and Cl-. HCl will take H+ out of solution and pH would increase, preventing solution from being acidic. |
What is an example of an effective buffer? | Carbonic Acid and Bicarbonate. This is because the RX takes place equally in both directions so it is effective to increase OR decrease pH. |