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146 Cards in this Set
- Front
- Back
What is the law of conservation of mass?
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mass is neither created nor destroyed in a chemical reaction
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What are the components of an atom?
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electron
proton neutron nucleus |
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What is the charge of an atom with 5 protons and 4 neutrons?
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+5
Atoms are electrically neutral, so the number of protons are balanced by the same number of electrons. In this case, 5(+1) + 4(0) = +5 |
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What is an isotope?
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have different nuclear properties and masses but the same chemical properties.
Basically, the isotopes have the same number of protons but differ in the number of neutrons. |
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What is the mass number?
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It is the sum of the protons and neutrons of an element.
It is used to distinguish isotopes from each other. |
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Identify the following groups on the periodic table:
I, II, VII, VIII |
I- alkali metals
II - alkaline earths VII- halogens VIII- noble gases |
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What is significant about all of the members of group VII on the periodic table?
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VII- halogens
they all have similar properties and they all react with hydrogen to from water soluble compounds. |
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Types of chemical bonds.
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covalent - sharing electrons
ionic - losing or gaining electrons |
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ionization energy
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the energy required to remove an electron from the outer shell of an element
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What is a miscible liquid?
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Liquids that dissolve in water.
e.g. alcohols |
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What is an acid?
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a substance that can donate a hydrogen ion.
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What is a base?
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a substance that can donate a hydroxyl ion.
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What is a neutralization reaction?
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a reaction between an acid and a base that results in a salt and water
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what is osmosis?
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diffusion across a semi-permeable membrane.
relies on osmotic pressure. |
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endothermic reaction
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reaction in which chemical bonds of the products have more energy than the reactants. Energy is required to make the reaction happen.
ATP is usually the energy source |
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What are catalysts and why are they important?
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Catalysts are usually enzymes.
They speed up a reaction and lower the activation energy |
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equilibrium constant
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the point at which reversible reactions have reached an equilibrium between the forward and backward reactions.
KA = reactants/products |
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define a strong acid or base
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one that is 100% ionized in aqueous solution
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what is the equation for pH?
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pH = -log(H+)
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What is the most important buffer in the blood?
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carbonic acid
H2CO3<->H + HCO3<-> H + CO3 |
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Henderson-Hasselbach equation
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pH=pKa + log proton acceptor/proton donor
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signal transduction
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the process of converting electrical information into chemical information
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4 features of signal transduction
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specificity
amplification desensitization/adaptation integration |
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3 classes of hormones
(that we focused on in class) |
peptides
steroids catecholamines |
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How do peptide hormones work?
name some examples |
They bind to cell-surface receptors.
e.g. insulin, glucagon, LH, FSH |
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How do steroid hormones work?
name some examples |
enter the cell and bind to receptors in the cytoplasm.
work at the level of transcription e.g. progesterone, estrogen, testosterone |
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How do catecholamines work?
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act through cell surface receptors to activate 2nd messenger
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endocrine secretory pathways
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endocrine
exocrine autocrine paracrine |
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regulated vs constitutive secretion
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regulated secretion- hormones are secreted in bursts, so they can be secreted in large amounts over a short period of time.
constitutive secretion - secreting as its synthesized |
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Are catecholamines proteins?
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NO
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How many electrons are in a covalent bond?
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2 and their spins are opposite
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What is the law of conservation of mass?
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the mass that enters into a chemcial reaction remains unchanged.
Chemical reactions do not create or destroy mass. |
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How do you figure out the mass of an atom?
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It's the sum of its protons and neutrons.
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How do you find the # of electrons of an element b y looking at the periodic table?
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the # of electrons = the # of protons of an element (the atomic number)
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What are valence electrons?
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Electrons located in the outer-most shell that are available to enter into chemical bonds.
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Define atomic number.
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The number of protons in a given element.
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How are the chemical properties of an element derived?
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chemical properties of an element are related to the number and char. of electrons in the outermost shell.
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what is an ion?
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an atom that has lost or gained an electron. a charged (either + or -) atom
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True or False
Elements on the right side of the periodic table lose electrons easily and elements on the left gain them. |
FALSE
Elements on the left lose electrons and elements on the right gain electrons easier. |
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What is meant by an electronegative element?
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An element on the right side of the periodic table, which means it GAINS electrons easily
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True or False
Electronegativity increases from left to right on the periodic table. |
True
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What is a polar covalent bond?
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a covalent bond that unequally shares electrons. The electrons are pulled toward one element more than the other.
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Avagadro's number
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6.02 x 10 to the 23rd
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molarity
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the amount of ions or molecules present in a given volume of solution
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1molar solution
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1M = one mole of a compound in 1 L of solution
one mole = formula weight in grams e.g. formula weight of CH4 = (1x12) + (4x1)=16 one mole = 16 grams |
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True or False
Water molecules are polar. |
TRUE
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Define solute and solvent.
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Solute - component of the solution in the smaller amount; that part dissolved in the solvent.
Solvent - component of the solution in the largest amount and that determines the physical state of the solution |
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Characteristics of a hydrophobic substance
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insoluble/poorly soluble in water
not charged not polar |
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Define immiscible.
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liquids that do not dissolve in water.
e.g. oil |
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Fill in the blank.
Gases are (more/less)_______ soluble in water as the temperature rises. |
LESS
Gases are less soluble in water as the temperature rises. |
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Fill in the blank.
Solids that dissolve in water are (more/less)_______ soluble in water as the temperature rises. |
MORE
Solids that dissolve in water are more soluble in water as the temperature rises. |
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What does it mean to have a polar covalent bond?
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bond where electrons are shared unequally, partial negative charges by the electronegative atom and partial positive charges by the electropositive atom
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True or False
All organic compounds containg the carboxyl group are weak acids. |
TRUE
It does not fully dissociate in water. |
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What is pH?
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the negative log of Hydrogen concentration
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What is dissociation?
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The process of ionization in weak acids and bases.
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Bronsted and Lowry theory
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acids donate protons.
bases accept protons. An acid becomes a base once it donates its proton. |
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Henderson-Hasselbach equation
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pH=pKa + log(proton acceptor/proton donor)
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Define radioactive isotopes and 4 types of radioactive emissions.
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Radioactive isotopes are elements with unstable nuclei that emit energy as particles or rays.
alpha particle - 2 protons and 2 neutrons (helium nucleus) beta particle - electron from the nucleus gamma ray - high energy electromagnetic wave with no mass or charge positron - positively charged particle the size of an electron |
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Beryllium has atomic number of 4 with an atomic wt of 9. How many neutrons are there?
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5 neutrons
atomic weight = protons + neutrons atomic number = # of protons |
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True or False
The electrons on the outermost shell are the least energetic and the easiest to lose. |
False
The electrons on the outermost shell are the MOST energetic. |
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CH4 has a formula weight of 16.
What is one mole of CH4? |
16
one mole equals the formula weight in grams. |
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molarity
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one mole of a compound in one liter solution
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Exothermic reaction
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What kind of reaction is this?
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Endothermic
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What kind of reaction is this?
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What 2 things can speed up an inorganic reaction?
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increasing the concentration of the reactants
increase the temperature |
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What is a halide?
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Any element in group VII of the periodic table. Chlorine is the most common.
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True or False
All elements with more than 83 protons are radioactive. |
TRUE
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True or False
Organic compounds usually have covalent bonds. |
True
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True or False
Inorganic compounds usually have covalent bonds. |
False
Inorganic compounds usually have ionic or highly polar bonds. |
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Characteristics of alkanes.
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consist of hydrogen and carbon
single bond between carbons end in -ane NOT polar NOT charged NOT water soluble ARE oil or lipid soluble |
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structural isomers
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more than one isomer for a particular chemical formula
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4 solubility characteristics of alkanes
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NOT polar
NOT charged NOT water soluble ARE oil or lipid soluble |
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alcohol
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What kind of structure is this?
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(alcohol)
methanol |
What kind of structure is this?
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aldehyde
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What kind of structure is this?
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aldehyde
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What kind of structure is this?
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(alkane)
ethane |
What kind of structure is this?
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alkene
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What kind of structure is this?
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alkyne
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What kind of structure is this?
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(alkyne)
acetylene |
What kind of structure is this?
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amide
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What kind of structure is this?
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(amide)
ethylamide |
What kind of structure is this?
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(amine)
methylamine |
What kind of structure is this?
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aromatic
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What kind of structure is this?
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carboxylic acid
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What kind of structure is this?
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(carboxylic acid)
ethanoic acid |
What kind of structure is this?
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ester
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What kind of structure is this?
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(ester)
methylethanoate |
What kind of structure is this?
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ether
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What kind of structure is this?
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ether
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What kind of structure is this?
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ketone
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What kind of structure is this?
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ketone
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What kind of structure is this?
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What are the 4 nucleotides of DNA?
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A G T C
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What is DNA replication?
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copying of the DNA strand before it divides into daughter strands so each daughter double helix has an original and a newly synthesized strand
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In what direction does DNA polymerase read?
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3 to 5 prime always
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What is the 'leading strand' in DNA replication?
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usually the top strand running 3 to 5 prime
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DNA polymerase
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enzyme that copies the DNA template or leading strand
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What kind of bonds are formed between DNA base pairs (A-T; C-G)?
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Hydrogen bonds
2 Hydrogen bonds between A-T 3 Hydrogen bonds between C-G |
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aliphatic vs. aromatic hydrocarbons
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aliphatic hydrocarbons lack a benzene ring
aromatic hydrocarbons have a benzene ring as part of their structure |
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solubility of unsaturated hydrocarbons
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insoluble in water
soluble in oil and fat not polar/uncharged |
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Are alcohols polar or nonpolar?
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Both.
They are polar at the OH end and nonpolar at the hydrocarbon end. |
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structural difference between aldehydes and ketones.
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aldehydes have hydrogen attached to the carboxyl group.
ketones have only carbons attached to the carboxyl group |
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What's the difference between a primary, secondary and tertiary amine?
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The number of hydrogens bound the nitrogen
primary - 2 hydrogens + R group secondary - 1 hydrogen + 2 R groups tertiary - 3 R groups (no hydrogen) |
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stereoisomerism
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configuration differences with the same connections between the atoms (cis/trans)
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optical isomer
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type of stereoisomer with a chiral carbon. The images are not superimposable.
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enantiomer
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mirror image stereoisomers that are not superimposable
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What are the 4 main steps of protein synthesis?
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DNA replication
DNA transcription RNA translation protein synthesis |
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peptide vs protein
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peptide-molecules comprised of less than 50 amino acids
protein-molecules comprised of more than 50 amino acids |
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general structure of amino acids
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carboxylic acid
an amino group a hydrogen atom R group side chain (this defines the uniqueness of the amino acid) |
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in mammals which enantiomers are present, L or D?
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only L
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True or False
Amino acids are symmetric. |
FALSE
Amino acids are assymmetric because they have 4 different constuents (carboxyl, amine, hydrogen and R-group); except glycine which has 2 hydrogens |
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What specifies the polarity of an amino acid?
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The R group
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What is pKa?
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the dissociation constant.
pH at which half the molecules of an AA are charged and half are uncharged |
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what constitutes a basic AA?
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R group has a nitrogen
high pKa value (so pH=10-12) |
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what constitutes an acidic AA?
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R group has a carboxyl group
low pKa negatively charged at physiologic pH |
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phosphorylation
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The addition of a phosphate group from ATP to an OH group of an AA. Makes the AA negative
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Which configuration is more common, cis or trans, and why?
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Trans because the R groups in the cis configuration tend to repel each other and are too large to be side by side.
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What determines the 'primary' protein structure?
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amino acid sequence
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What determines the 'secondary' structure of a protein?
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alpha helix or beta sheet structure
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What determines the 'tertiary' structure of a protein?
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3-D structure of the folded protein where hydrophobic side chains are internal, hydrophilic or ionized side chains face outward
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What is a peptide bond
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a dehydration reaction b/w 2 amino acids joining the carboxylic acid of one amino acid to the alpha-amino group of another amino acid.
it is a covalent bond. |
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True or false
Cis and trans configurations are common in secondary structure of polypeptide bonds. |
FALSE
Cis configuration is rare because the R-groups repel each other and are too large to be side by side. |
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Primary structure
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the amino acid sequence of a polypeptide
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secondary structure
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local 3-D folding of a polypeptide chain
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cysteine bond
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disulfide covalent bond between two cysteine amino acids
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tertiary structure
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3-D structure of a polypeptide
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What 2 secondary structures are the most observed in naturally occurring polypeptides?
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alpha-helix
beta sheet |
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alpha helix
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secondary structure
alpha helix formed by hydrogen bonds with every 4th amino acid down the chain |
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beta sheet
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secondary structure
side-by-side parallel or ant-parallel alignment of polypeptide chains, each bound by hydrogen bonds |
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True or False
All proteins have a quaternary structure. |
FALSE
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quaternary structure
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noncovalent relationship b/w 2 or more polypeptides to form a multiunit protein
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ligand
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molecules that reversibly bind to other molecules
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What is a prosthetic group?
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a compound that permanently associates with a protein and contributes to its function
e.g. heme prosthetic group |
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oxidation or reduction reaction
ferrous (+2) to ferric (+3) |
oxidation reaction
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What is the significance of iron (+3) in hemoglobin?
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this is methemoglobin. oxygen won't bind to the heme group while iron is in this state.
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define: hemoglobin
myoglobin |
hgb-oxygen binding molecule in the blood; consists of 4 protein chains and 4 heme groups
myoglobin - oxygen binding molecule in the skeletal muscle |
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allosteric protein
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the binding of a ligand to one site affects the binding properties of another site on the same protein
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What is the T-state of Hgb?
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the tense state with no oxygen bound to the heme groups
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What is the R-state of Hgb?
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the relaxed state. As one oxygen binds to a heme group, it results in a conformational change in another heme group increasing its affinity to oxygen until all sites are filled.
Hgb is an allosteric protein! |
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genome
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the complete set of informtion carried by DNA
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intron
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non translated sequence that interrupts the linear code
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exon
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coding segment for nucleotide sequence
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types of RNA
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rRNA-ribosomal
mRNA-messenger tRNA-transfer |
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rRNA-
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ribosomal RNA
most abundant type of RNA in a cell carries out translation |
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topoisomerase
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enzymes that break and rejoin strands of DNA, producing a superhelix
|
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True or False
RNA is linear and single stranded. |
TRUE
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