Week 1

Description:	09/11/07
Category:	Chemistry
Created by:	PCC Biochemistry I on 2007-09-12

Questions	Answers
Q: What is the maximum amount of electrons an atom can have in its innermost shell?	A: Two.
Q: What is the maximum amount of electrons an atom can have in its outermost shell?	A: Eight.
Q: The outermost shell of an atom is referred to as what?	A: The valence shell.
Q: The way in which atoms react with one another is based on what?	A: The electrons in the outermost shell referred to as valance electrons.
Q: True or False? Atoms will always gain electrons in order to fill their outer shells.	A: False! Atoms with incompletely filled outer shells tend to GAIN, LOSE, or SHARE electrons in ways to EMPTY or FILL their outer shells and create a stable structure.
Q: What is the "Rule of Octets" or the "Octet Rule"?	A: Except for the first energy level, atoms react with other atoms so they will have 8 electrons in their valence shell.
Q: What is another name for an electrovalent bond?	A: An ionic bond.
Q: What is an ion?	A: An atom that has lost or gained electrons to fill their valence shell.
Q: A negative ion is referred to as what?	A: An anion.
Q: A positive ion is referred to as what?	A: A cation.
Q: What is an ionic bond?	A: A bond formed between two oppositely charged ions.
Q: Give an example of an ionic interaction found in biological molecules.	A: Salt bridges.
Q: What is a covalent bond?	A: A bond formed when atoms share electrons.
Q: True or false? A covalent bond is a strong bond.	A: True!
Q: What is a nonpolar covalent bond?	A: A covalent bond where electrons are shared equally.
Q: Give an example of a nonpolar covalent bond.	A: Hydrogen (H2), Oxygen (O2).
Q: What is a polar covalent bond?	A: A covalent bond where electrons are shared unequally causing partial negative and positive regions.
Q: Give an example of a polar covalent bond.	A: Water (H20)
Q: What is a hydrogen bond?	A: A hydrogen bond is a weak bond formed between hydrogen atoms (that are covalently bonded to another atom) and another atom.
Q: True or false? Hydrogen bonds are important in intra-molecular bonds.	A: True! They bind different parts of the same molecule, which helps maintain structure of protein molecules and DNA chains.
Q: What is the most abundant component in cells?	A: Water, making up about 70% of cells and 2/3 of human body weight.
Q: True or false? Most biochemical reactions occur in aqueous solution.	A: True!
Q: Give two examples of the importance of water discussed in class.	A: Transport of chemicals into the body and thermoregulation.
Q: What is the approximate percentage of water compostion in humans?	A: 63% for males, and 52% for females.
Q: What are the two major fluid compartments in humans and what is the relative percent of each?	A: The intracellular fluid compartment (ICF), about 63% of total water and the extracellular fluid compartment (ECF), about 37% of total water.
Q: What contains more water, the ICF or ECF?	A: The ICF.
Q: True or false? Water is wierd.	A: True!
Q: Water is liquid in what temperature range.	A: 0-100 degrees celsius.
Q: What is meant by high heat capacity?	A: Absorbs and releases large amounts of heat very slowly before temperature changes appreciably.
Q: What is meant by high heat of vaporization?	A: Requires a lot of heat to change from a liquid to a gas.
Q: Define an amphipathic molecule.	A: A molecule with both polar and nonpolar groups.
Q: Give an example of an amphipathic molecule.	A: Phospholipids.
Q: True or false? Hydrophilic molecules are soluble in water.	A: True! Hydrophilic molecules are polar and suluble in water.
Q: True or false? Hydrophobic molecules are soluble in water.	A: False! Hydrophobic molecules are nonpolar and insoluble in water.
Q: What is dehydration (synthesis)?	A: Dehydration (synthesis) is when water is removed from adjacent atoms (of molecules) to form a bond between them.
Q: What is hydrolysis (degradation)?	A: Hydrolysis (degradation) is when water is used to break bonds between molecules.
Q: What is osmosis?	A: Diffusion of water molecules through a selectively permeable membrane from a region of higher concentration to a region of lower concentration.
Q: What is osmotic pressure?	A: The pressure required to stop the net flow of water across the membrane.
Q: What is a hypertonic solution?	A: A solution with a higher solute concentration relative to a cell... cell will crenate.
Q: What is a hypotonic solution?	A: A solution with a lower solute concentration relative to a cell... cell will swell or lyse.
Q: What is an isotonic solution?	A: A solution with the same solute concentration relative to a cell... causes no change in a cell.
Q: For our purposes in this class, what is an acid?	A: A proton donor; donates hydrogen ions (H+) to a solution.
Q: For our purposes in this class, what is a base?	A: A proton acceptor; removes hydrogen ions (H+) from solution.
Q: True or false? Weak acids and bases do not completely dissociate in water.	A: True!
Q: True or false? Strong acids and bases rapidly & completely dissociate in aqueous solution.	A: True!
Q: Did you know... ?	A: Most acids and bases in the extracellular fluid are weak acids and bases.
Q: The stronger the acid, the _______ the Ka.	A: Larger.
Q: The stronger the acid, the _______ the pKa.	A: Lower.
Q: What does the acid dissociation constant (Ka) indicate?	A: The tendency of the acid (HA) to lose its proton and form its conjugate base (A-).
Q: What is the formula for Ka?	A: Ka = [H+][A-] / [HA]
Q: What is the formula for pKa?	A: pKa = -log Ka
Q: What is the formula for pH?	A: pH = -log [H+]
Q: What is the pH of water (neutral)?	A: Seven.
Q: A solution whose hydrogen ion [H+] concentration is less than its hydroxide ion [OH-] concentration is said to be _______.	A: Basic or alkaline.
Q: A solution whose hydrogen ion [H+] concentration is greater than its hydroxide ion [OH-] concentration is said to be _______.	A: Acidic.
Q: Having a pH less than 7.35 is referred to as what?	A: Acidosis.
Q: Having a pH greater than 7.45 is referred to as what?	A: Alkalosis.