Chem/Phys Flashcards
How is a peptide bond formed?
Lone pair of electrons on amino-terminus nucleophilically attacks the carbonyl carbon of another amino acid’s carboxy-terminus
Primary structure of protein
Linear sequence of amino acids connected by peptide bonds
Secondary structure of protein
Local structure consisting of alpha-helices and beta-pleated sheets.
Stabilized by hydrogen bonds
Tertiary structure of protein
3D structure stabilized by hydrophobic interactions, acid-base interactions, hydrogen bonding and disulfide bonds.
R-groups contribute to polypeptide’s tertiary structure
Quaternary structure of protein
Interactions between subunits.
Heat and solutes cause denaturation of quaternary structure
Which amino acid is not chiral?
Glycine, therefore it is also not optically active
Why is atomic oxygen highly reactive?
It is a free radical because it has unpaired valence electrons
What do nucleophiles possess that make them highly reactive?
Unpaired electrons - this is why they are often negative
What is the Grignard reaction used for?
Formation of carbon-carbon bonds
What is the relationship between index of refraction and speed of light?
Smaller index = faster light
How are Polysaccharides connected
Carbohydrate-carbohydrate glycosidic bonds
Rate law notations
0th: rate=k
1st: rate=k[A]
2nd: rate=k[A][B] or Rate=k[A]^2
What is the function of a buffer?
How many pKa’s does a triprotic acid have?
Resists changes in pH.
Triprotic acids have 3 pKa’s
How is Rf values (in chromatography) related to polarity?
Silica plates are very polar. Therefore polar molecules will have lower Rf values while non polar molecules will have higher Rf values
Enzymes ONLY affect what?
Reaction rate
Which nucleic acid bases are purines?
Adenine & guanine
Which nucleic acids are pyrimidines?
Uracil thymine and cytosine
How do the bonds between A-T and C-G differ?
A-T has two hydrogen bonds
C-G has three hydrogen bonds
What is the relationship between pH and CO2 in the body?
Increased CO2 = decreased pH
What is the charge of the anode of an electrolytic cell?
Cathode?
Anode = positive
Cathode = negative
What is the charge of the anode of an galvanic cell?
Cathode?
Anode = negative
Cathode = positive
What is the charge of the anode of an gel electrophoresis?
Cathode?
Anode = positive
Cathode = negative
Which way does electric CURRENT flow?
From positive to negative
In a simple circuit the flow of current is the opposite of the flow of electrons (electrons are attracted to the positive)
Which way do electrons flow?
Anode to cathode ALWAYS
AN OX RED CAT
What is the charge of a cathode and anode in a simple circuit?
Anode = negative
Cathode = positive
How are acetal and hemiacetals formed?
Addition of an alcohol onto a carbonyl group of an aldehyde
Sound waves travel fastest through what kind of media?
Solid media
What is Gibbs free energy equation?
G = H - T(S)
What is the difference between observed rotation and specific rotation?
Specific rotation is a constant (unless chemical changes occur)
Observed rotation is simply the rotation one can see (like an Orgo student in a lab)
What does Benedict’s test used for?
Testing for reducing sugars
What is a reducing sugar?
A reducing sugar has a hemiketal or hemiacteal group
What is the common ion effect?
The common ion effect is responsible for the reduction in the solubility of an ionic precipitate when a soluble compound containing one of the ions of the precipitate is added to the solution in equilibrium with the precipitate.
When does respiratory alkalosis occur?
When you hyperventilate
When does delocalization of electrons occur
When resonance is present
How do you calculate formal charge
Valence - bonds - nonbonded electrons
What is cloud point?
The point where a solution is on the brink of precipitation.
Lowering temp or adding solute will cause precipitation
What is the difference between a dehydration and hydrolysis reaction
Dehydration reaction links two monomers together by releasing water
Hydrolysis breaks polymers apart using water
How do you determine how many stereoisomers are possible in a compound?
2^n
Where n is the number of chiral centers
How do you determine the centripetal force?
F = m(v^2/r)
Tertiary alcohols experience what kind of reaction when attacked by a nucleophile?
SN1 reaction
Primary alcohols experience what kind of reaction when attacked by a nucleophile?
SN2 reaction and therefore the absolute conversion is inversed
What is the difference in types of products SN1 reactions create versus sn2 products?
Sn1 = racemic mixture
Sn2 = optically active and inverted
What’s the difference between an alpha particle and a helium atom
An alpha particle is simple the helium nucleus (no electrons)
What is the relationship between normality and molarity?
What is the molarity of a 1 N solution of HCl?
What is the molarity of a 30N solution of H2SO4?
Normality of a solution is the molarity multiplied by the number of equivalents per mole
HCl has a molarity of 1 M
H2SO4 has a molarity of 15 M
How is current related to time?
Current = charge/time
How are cations formed in regard to principal quantum number?
Electrons are removed beginning with highest principal quantum number
I.e: 4s2 before 3d10
What is a Lewis base?
A Lewis acid?
A Lewis base is an electron donor
A Lewis acid is an electron acceptor
What is a Brønsted-Lowry acid?
A Brønsted-Lowry base?
Brønsted-Lowry acid = proton (H+) donor
Brønsted-Lowry base = proton acceptor
What is a saturated solution?
A solution in which no more solvent can be dissolved
What is the first step in stoichiometry problems?
Convert the mass to moles
What is a colloid?
Suspension of particles that are larger in size than that of an individual molecule
What color has the highest frequency?
What color has the highest wavelength?
Frequency = purple
Wavelength = red
What is the unit of a Watt
Joules/second
How does resistance relate to resistivity?
Resistance = p(L)/A
What is superheating of a liquid?
Heating a liquid under pressure above its boiling point without vaporization
What does a red litmus color represent?
What does a blue litmus color represent?
Red = acidic
Blue = basic
In aqueous solutions what does H2CO3 decompose to?
H2O and CO2
What is an aliphatic compound?
A compound that is not aromatic - it is a straight chain compound
What is tautomerization?
Tautomerization involves the movement of atoms typically H. Resonance deals with the delocalization of electrons
What does the reactivity of a metal depend on?
Ionization potential
What are the best leaving groups?
What are the worst leaving groups?
Best leaving groups = weak bases
Worst leaving groups = strong bases
How does an acid differ from its conjugate base?
By the presence of a H+
What occurs if the solubility product of a compound is exceeded?
A precipitate will form
What does a low ksp mean in regards to water solubility?
Low ksp = low solubility in water
When does a liquid boil in regards to its vapor pressure and atmospheric pressure?
A liquid will boil when the vapor pressure = atmospheric pressure
How many electrons can fit in the s, p, d and f orbitals?
S= 2
P= 6
D= 10
F= 14
In titration, how do the moles of analyte compare to the moles of titrant at the equivalence point?
Moles analyte = moles titrant at equivalence point
What are the 3 kinematics equations?
Vf = Vo + at
Xf = Vot + 1/2 at^2
V^2 =Vo^2 + 2a(Xf-Xo)
What does Newton’s third law state?
For every force there must be an equal and opposite force
What are the bond angles for a sp, sp2, sp3 molecule?
Sp = 180
Sp2 = 120
Sp3 = 109.5
Acetone formula
C3H6O
What do each of these enzyme classes do?
Oxidoreductase Transferase Hydrolase Lyase Isomerase Ligase
Oxidoreductase = oxidation or reduction reactions
Transferase = transfer of function groups
Hydrolase = Hydrolysis reaction
Lyase = cleavage without hydrolysis
Isomerase = create isomers (rearrangement of atoms within a molecule)
Ligase = Joining of two molecules using ATP
Where are the following IR spec peaks located?
Carbonly, Hydroxyl, Amine
Carbonly = 1700-1750
Hydroxyl = 3200-3500 (broad)
Amine = 3100-3500 (sharp)
What does k equal to in regards to
k = [products]/[reactants]
What is Hess’s Law?
deltaH = ∑Hproducts - ∑Hreactants
What does a capacitor do?
Stores an electric charge
Microtubules are used in which of the following:
Meiosis
Mitosis
Vesicle transport
Microtubules are used in all 3
What is 1atm equal to in mm Hg and in Pa
1 atm = 760 mm Hg = 10^5 Pa,
What kind of images do diverging lens produce?
What kind of images do converging lens produce?
Diverging = SUV - smaller upright virtual
Converging = SIR EIR LIR no LUV
SIR = beyond R EIR = object at R LIR = object between R and F no = at focal point LUV = between f and lens
What is an example of a molecule that exhibits homotropic regulation?
Hemoglobin
Where is an indicators pKa?
Within one unit of the desired pH
What is the difference between a positive control and a negative control?
Positive control = response expected
Negative control = no response expected
How are work and KE related
W = change in KE
What is 1 Pa equivalent to?
1 N/m^2
1 L is equivalent to what?
1 m^3
1 J is equivalent to what?
1 N.m
How is velocity and pressure related?
Increased velocity = decreased pressure
What is the equation for flow?
Flow= Area x velocity
What is an acetyl group?
A methyl and carbonyl group is an acetyl group