Things you must commit to memory for mcat bs & ps

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Any help with optic? I find the different type of lens and mirrors and what their properties really confused the heck out of me.
 
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Atny said:
Any help with optic? I find the different type of lens and mirrors and what their properties really confused the heck out of me.
Click to expand...

UV-IR upright is virtual, inverted is real (any single mirror/lens)

diverging systems always produce a small, upright, virtual image (SUV)
 
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Atny said:
Any help with optic? I find the different type of lens and mirrors and what their properties really confused the heck out of me.
Click to expand...

Inverted Real (IR)
Upright virtual (UV)
you can never have a inverted virtual or an upright real image. i suggest chad's videos for optics and also for orgo too.
http://www.coursesaver.com/videos/MCAT/

I'll add some other memorized things that I can quickly think of:
sqrt(3)=1.7 and sqrt(2)=1.4 - pretty easy but important for sin and cos
know the most commonly seen IR and NMR peaks
know all the physics equations and how the units relate (very important)

there's a lot more but i took my test almost 2 months ago and am having trouble recalling others. my advice is to take as many practice FSQ's and passages as you can manage. do you have any online review materials? i used TPR and highly recommend it. PM if you want.
 
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Atny said:
Any help with optic? I find the different type of lens and mirrors and what their properties really confused the heck out of me.
Click to expand...

Some formulas (SIGNS MATTER):
  1. 1/f = 1/o + 1/i
  2. M (magnification) = - i/o
  • (+) means it is on the real side of the lens (right) and mirror (left); for M it means the image is upright
  • (-) means it is on the virtual side of the lens (left) and mirror (right); for M it means the image is inverted

Some notation: o is object distance, i is image distance, f is focal length, 2f is radius of curvature. S is smaller, I is inverted, R i real, V is virtual, SS is same size, L is larger.

Here we go:
  1. a concave lens and a convex mirror are diverging
    • all produce SUV between -f (f on the virtual side) and the optical device (lens or mirror)
  2. a convex lens and a concave mirror are converging
    • if o is further than 2f, then SIR between f and 2f
    • if o is at 2f, then SSIR at 2f
    • if o is between 2f and f, LIR beyond 2f
    • if o is at f, then no image is formed
    • if o is within f, LUV at -f
 
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Also, here's an easy way to remember AA's.
  1. If the R group contains any of the following it is polar:
    • amines - also means it is basic: ie. histidine, lysine, arginine
    • amides - means it's an acid derivative: ie. asparagine, glutamine ; also means it is acidic if you replace the amide with a COOH: ie. aspartic acid, glutamic acid
    • alcohols - ie. serine, threonine ; includes thiols: ie. cysteine
  2. If the R group contains an aromatic group it can be:
    • phenylalanine = alanine + phenyl ring
    • tyrosine = phenylalanine + para-hydroxyl
    • tryptophan = alanine + indole ring (=benzine ring + N-containing pyrrole ring)
  3. The rest are hydrophobic, they can be:
    • valine - isopropyl group
    • leucine - ethyl isopropyl group
    • isoleucine - alkyl shift of leucine
    • methionine - contains sulfur
    • proline - annoying ring involved in kinks
  4. Also don't forget (doubt you will) the small ones:
    • glycine - H
    • alanine - methyl
 
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azor ahai said:
Some formulas (SIGNS MATTER):
  1. 1/f = 1/o + 1/i
  2. M (magnification) = - i/o
  • (+) means Tis on the real side of the lens (right) and mirror (left); for M it means the image is upright
  • (-) means Tis on the virtual side of the lens (left) and mirror (right); for M it means the image is inverted
Some notation: o is object distance, i is image distance, f is focal length, 2f is radius of curvature. S is smaller, I is inverted, R i real, V is virtual, SS is same size, L is larger.

Here we go:
  1. a concave lens and a convex mirror are diverging
    • all produce SUV between -f (f on the virtual side) and the optical device (lens or mirror)
  2. a convex lens and a concave mirror are converging
    • if o is further than 2f, then SIR between f and 2f
    • if o is at 2f, then SSIR at 2f
    • if o is between 2f and f, LIR beyond 2f
    • if o is at f, then no image is formed
    • if o is within f, LUV at -f
Click to expand...
Everything else make sense except the magnification m=-i/o, +m = up right, -m= inverted, don't work when i test it on stuff like convex len.
 
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This is partially for my own records, in case I need to retake. Here are the things that I really need to memorize for the MCAT, I cannot intuitively guess these things:

Snell's Law (refraction):

Equation:
sin(t1) / sin(t2) = v1 / v2 = n2 / n1

Explanation:
t means theta, which is angle. The angle is measured relative to the "normal vector", which is perpendicular to the surface. t1 is the angle in medium 1. v1 is the velocity of the wave in medium 1. n1 is the index of refraction of medium 1.

Mnemonic:
Use SINES, do not use cosines. (Once I remember that it is sines, then I remember that it is the normal vector, and everything else is intuitive from there.)

Gibbs Free Energy, Enthalpy, and Entropy:

Equation:
ΔG = ΔH - T*ΔS

Explanation:
ΔG negative <--> spontaneous <--> exergonic
ΔH negative <--> exothermic
ΔS positive <--> favored, but no specific term for this
 
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Pretty cool! Keep it going people, let turn this in the number one topic!!!!

Many thanks
 
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- Know the Hardy-Weinberg equation and how to use it properly.
- Know the difference between diastolic and systolic.
- Know the germ layers and what they give rise to.
- Understand the difference between germ and somatic cells and how mutations would effect either the progeny or the individual.
- Know the difference between misense, nonsense, and silent mutations.
- Know that frameshifts can only occur with a deletion or insertion of less or more than 3 nucleotides.
- Understand what histones are, the molecular basis for binding to DNA, and knowing this, determine potential aminoacid composition.
- Understand enzyme function and regulation; feedback inhibition; what products accumulate with a given enzyme mutation? what key enzymes might be regulated by feedback inhibition?
- Know how to read and interpret a damn table, because 99% of the time, the answer is right there in front of you.

Your test will have at least 3 of these concepts as stand alones, guaranteed. You can thank me later.
 
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v = wavelength x frequency

m1v1=m2v2
and for an inelastic collision m1v1 = (m1 + m2)v2

On an incline, the normal force is mgcos(theta) and the vector pointing downward (parallel to the incline) is mgsin (theta). It feels opposite to intuition but that's the way it is.

The normal force decreases as the incline gets steeper (or more toward a 90 degree angle)
 
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i've used some a.a. mnemonics i found on a quizlet that are pretty raunchy. they definitely helped me remember. lol.

i didn't make these up and not sure who did. I hope no one's offended, but i promise you won't forget them:

non-polar:
Get A Vagina LIP To My Penis
1. Glycine
2. Alanine
3. Valine
4. Leucine
5. Isoleucine
6. Phenylalanine
7. Tryptophan
8. Methionine
9. Proline

polar:
Some Times There Are Good *****
1. Serine
2. Tyrosine
3. Threonine
4. Asparagine
5. Glutamine
6. Cysteine

basic:
Hot Little Ass
1. Histidine
2. Lysine
3. Arginine

acidic:
Acid is All Good
1. Aspartic Acid
2. Glutamic Acid

http://quizlet.com/46112394/amino-acids-flash-cards/
 
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Woohoo, please keep them coming. If 1 person contribute 10 things. 1000 people = 10,000 things. Big wow!
 
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Does anyone know how to conquer electrochemistry? I found the half reaction and voltage potential confusing the living heck out of me.
 
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What is this:

Q=mc(delta T)

Atny originally said it, but I am guessing many people can identify it.
 
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Are you actually asking?

Or are you posing a challenge? I can't tell.

Either way that is a formula I would expect anyone who has taken chemistry or physics to have used quite often.
 
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I am honestly asking, I have no idea. Is Q charge? Is T temperature or time? Is m mass? Is c the speed of light?

I may well have used it on the MCAT, but I don't think I know it in that arrangement or with those variable symbols. I tried Google and SymbolHound search engines and could not find this equation.
 
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Oh, I definitely don't remember that equation in that format. I just remember the units of specific heat, and I can derive anything I need. Problems will usually state the units of specific heat, so you don't even need to memorize that.

Specific heat = 1.5 J / (K * g)

Okay, therefore:

c = Q / (ΔT * m)

Rearrange as needed to solve for ΔT, Q, or mass.
 
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Sure. It's just pretty common to have to know for chemistry and physics.

I guess that works.
 
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Atny said:
Does anyone know how to conquer electrochemistry? I found the half reaction and voltage potential confusing the living heck out of me.
Click to expand...

just do a bunch of e chem problems and you'll start to see the same half reactions pretty frequently. i always thought of them as a puzzle. for it to be spontaneous, E = + (opposite of deltaG spontaneity). i already suggested chad's videos previously, but will plug him again. it's a low cost option for lecture videos that really lay out each topic very well. you can subscribe for one month for like $30 or something. http://www.coursesaver.com/videos/MCAT/
 
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Only frequency stays the same when light goes from one medium to another.

- velocity & wavelength change depending on the index of refraction
 
Last edited:
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Thoroughbred_Med said:
Only VELOCITY changes when light goes from one medium to another.

- freqency & wavelength stay the same
Click to expand...

Wait... I thought the wavelength does change and frequency changes?
Picture is from EK...
JCaIwMB.png
 
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Kate2 said:
Haha I was just reading this chapter and was like wait a minute 🙂
Click to expand...

Yep. You were so right. I revised my post.

Velocity and wavelength are directly proportional and, therefore, change accordingly to the medium (n=c/v). Frequency is nowhere in that equation and so doesn't get altered.
 
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Basic math tips and tricks are indispensible!

Logs:
using base10, log(1000)=3 is equiv to 10^3=1000
log(2)=0.3, log(3)=0.48 (thanks BR)
the common log rules, like log xy = log x + log y

Fractions:
memorizing stuff like 1/6=0.1666, 1/7=0.143

Knowing what an inverse 1/x graph looks like...

And of course my weakest concept, acid base chem :whistle:
pH=-log[H+]
H-H: pH=pKa+log([A-]/[HA])
 
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suchbrio said:
Basic math tips and tricks are indispensible!

Logs:
using base10, log(1000)=3 is equiv to 10^3=1000
log(2)=0.3, log(3)=0.48 (thanks BR)
the common log rules, like log xy = log x + log y

Fractions:
memorizing stuff like 1/6=0.1666, 1/7=0.143

Knowing what an inverse 1/x graph looks like...

And of course my weakest concept, acid base chem :whistle:
pH=-log[H+]
H-H: pH=pKa+log([A-]/[HA])
Click to expand...

Yes! Thank you BR for your log math tricks!!!
 
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Mole=gram/molar mass
M=n/L

Can some expert here add some knowledge to solution chemistry and color of solution and solubility?
 
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  • I have had G = H - TS on every single AAMC practice test in every form and fashion. Know those variables backward, forward, crossways, negative, exo, endo, and whatever else. This also goes hand-in-hand with reaction diagrams and activation energies.
  • Law of Reflection, especially when changing between mediums. Incidence angles, refraction angles, and what happens when n1 is higher index than n2 or vice versa....
  • Doppler equation, and how each variable of sound changes when the source/listener moves.
  • Redox reactions and oxidation numbers.
  • IR values for certain groups (carbonyl, hydroxyl...) have also popped up on every practice test.
  • Friction: on a plane, in the snow, on a road (sounds like Green Eggs and Ham)
  • Free-falling objects and all the equations that go with it.
  • Stoichiometry. 'Nuff said
  • Half lives and decay particles are very frequent, as well. Do some problems with a positron, alpha particle and beta particle.
  • Punnett squares, every test. Know co-dominance and sex-linked disorders
  • Hormones, of course; especially those that act on kidney function.
 
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TXhopeful said:
  • I have had G = H - TS on every single AAMC practice test in every form and fashion. Know those variables backward, forward, crossways, negative, exo, endo, and whatever else. This also goes hand-in-hand with reaction diagrams and activation energies.
  • Law of Reflection, especially when changing between mediums. Incidence angles, refraction angles, and what happens when n1 is higher index than n2 or vice versa....
  • Doppler equation, and how each variable of sound changes when the source/listener moves.
  • Redox reactions and oxidation numbers.
  • IR values for certain groups (carbonyl, hydroxyl...) have also popped up on every practice test.
  • Friction: on a plane, in the snow, on a road (sounds like Green Eggs and Ham)
  • Free-falling objects and all the equations that go with it.
  • Stoichiometry. 'Nuff said
  • Half lives and decay particles are very frequent, as well. Do some problems with a positron, alpha particle and beta particle.
  • Punnett squares, every test. Know co-dominance and sex-linked disorders
  • Hormones, of course; especially those that act on kidney function.
Click to expand...
Please give us any hormone and what they do you know that may be going to be on the MCAT. Thanks.
 
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DesertSeaDiver said:
i've used some a.a. mnemonics i found on a quizlet that are pretty raunchy. they definitely helped me remember. lol.

i didn't make these up and not sure who did. I hope no one's offended, but i promise you won't forget them:

non-polar:
Get A Vagina LIP To My Penis
1. Glycine
2. Alanine
3. Valine
4. Leucine
5. Isoleucine
6. Phenylalanine
7. Tryptophan
8. Methionine
9. Proline

polar:
Some Times There Are Good *****
1. Serine
2. Tyrosine
3. Threonine
4. Asparagine
5. Glutamine
6. Cysteine

basic:
Hot Little Ass
1. Histidine
2. Lysine
3. Arginine

acidic:
Acid is All Good
1. Aspartic Acid
2. Glutamic Acid

http://quizlet.com/46112394/amino-acids-flash-cards/
Click to expand...

You were definitely right about not forgetting them. That's hilarious.
 
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12/06 taker and from what I can remember...

Atomic & Nuclear structure--TBR is good with breaking down the concepts, yet some info can be superfluous.
Stochiometry--Be comfortable with doing the math & doing it fast.
Ochem Lab Techniques--KNOW ALL OF THEM, even gas chromatiography or any of the less common techniques 🙂
Waves--MCAT loves using v=speed x frequency and E=hf, along with EM radiation
Doppler effect--understand it conceptually (don't remember quite if this was on our test, but it was tested a lot on AAMC FL
Hormones--enough said
Acid & Bases--henderson hasselbach eqn, understanding pH generally and in relation to AA when in a certain environment

Last 3 tips are focused more on critical thinking and reasoning. The BS, and unfortunately PS section have included more passaged-based questions, so your interpretation of the passage is VERY VERY IMPORTANT.

UTILIZE THE DIAGRAM/GRAPH/TABLE--they are in the passage for a reason.
KISS IT--keep it simple stupid. Use what the passage gives you!
USE POE agressively--eliminate wrong answers FIRST, (i.e. use the strike out fx A LOT)


I hope this helps!
 
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Also, if you have found that you are pretty good with Verbal, then I would recommend applying those techniques with the PS/BS passage-based questions.
 
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