MCAT Mistakes Flashcards
Mass Spec: What is difference between parent peak and base peak?
Base Peak: The peak with highest relative abundance (intensity), value set to 100%.
Parent Peak: The peak that references the atomic mass of the initial molecule.
What is the McLafferty Rearrangement?
O=CH2-CH2-CH2-CH3
HO-CH-CH2 + H2C=CH2
The gamma carbon on a carbonyl loses an H, which goes to the O, bonds rotate cyclically and the final product is an enol and an alkene.
Gel electrophoresis, what are the charges at the anode and cathode? To where does an anion travel?
Cathode is negative. Anode is positive.
Anions travel to the anode. Cations travel to the cathode.
What is the isoelectric point?
The pH at while a molecule carries no net electrical charge.
What does reverse transcriptase make?
cDNA.
What is the difference between the epiblast and hypoblast?
Epiblast: primitive ectoderm
Hypoblast: primitive endoderm
What is the corpus luteum?
The ovum is held in a follicle, when it is released, the follicle that is in the ovary is degraded and reabsorbed. The degrading follicle is called the corpus luteum.
During what phase of the menstrual cycle is a woman able to get pregnant?
Follicular phase.
Not able to get pregnant during Luteal phase.
A mutation in what position of the codon will least likely have a negative impact?
A mutation in the third position, the wobble spot.
Higher Ka/Kb means what?
Higher acidity/basicity.
What are electrolytic techniques used for in terms of purification?
It can be used to isolate a product by the decomposition of other products. Also can be used to separate a brine (NaCl).
What is fractional distillation used for?
Use different boiling points to separate materials in solution.
What is the value of Ecell?
SUM of the half rxns.
Does molar absorptivity have units?
NO.
molar absorptivity = A = ecl (‘e’ is a constant)
What are the endpoints of the visible spectrum from shortest to longest wavelengths?
UV < purple < red < infrared
- Electromagnetic waves are _________?
2. Sound waves are ____________?
- Transverse
2. Longitudinal
Periodicity refers to T or f?
What is the equation to calculate speed from periodicity?
T (period)
v = wavelength/T
Which number is greater: -n/9 or -n/5?
-n/9 > -n/5
How does a pH indicator work?
- changes color over specific pH range
- depends on when HA -> H+ and A-
- consequently, depends on pKa
How do you calculate number of possible stereoisomers?
2^n (n = # of stereocenters of the molecule)
Are H’s on alpha carbons more acidic for carbonyls or esters?
carbonyls.
TLC, do polar or non-polar substrate travel more and have a higher Rf?
Non-polar = higher Rf
Near sited people need what sort of lense?
Divergent.
Image is focused in front of retina and divergent lens help to push the image back onto the retina.
What is the F factor on a plasmid associated with?
Conjugation
