The Official 3/23/13 MCAT Thread

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Figured I'd start this one out. I'll be registering for the MCAT first thing tomorrow. Who else is taking it on this date? How do you all plan on studying over the school year?
 
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NuttyEngDude said:
hmmm... do you use the TPR or TBR method for logs?

right now i'm sort of just memorize what log 2 and log 3 are then estimating based on that but i'm not adding it up like how TBR suggests.
Click to expand...

I use TBR's method. Memorize log(2), (3), and (7), know log manipulation rules, and use the above tricks I call the z-y log rearrangement and the log trick of 3's and that usually covers me. TBR does some more extensive log math, but that's usually only required for decimal log subjects.

Jr that's basically what I do, but I realize you probably need a more detailed explanation that than since that's pretty vague and can't really be followed if you don't already know what I'm talking about, so I'll post one for you when I have time. It's late...
 
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Yea i asked the question before i read tbr method...its freaking legit lol

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gettheleadout said:
TBR does some more extensive log math, but that's usually only required for decimal log subjects.
Click to expand...

the more extensive stuff actually messed me up, so i dont use it... at all... 😛 hasnt hurt me yet except on some TBR passages or examples where they go out to the 2nd decimal place or something. i dont see anyone else being THAT Exact on their practice material so i'm making the call to not try to be so exact. i've found the more arithmetic i do the more mistakes i make, i should look to fix this.... maybe......but i feel my time is better spent sharpening concepts
 
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No rush at all...you've helped enough for today gtlo thanks alot

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Does anyone know a good source of practice problems similar to that of the EK 1001 physical sciences workbook? I could use more practice on magnetism, circuits, and acid/base problems.
 
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Just a helpful way to memorize formulas for spring system and pendulum system. Hope this helps anyone struggling with the memorization.

For the spring systems I remember the period formula as Too Much Knowledge. T= 2pi sq rt of M/k

For the pendulum: this one may not work as well, but I love this show the league on FX and so The LeaGue is
T= 2pi sq rt of L/G.

These help me remember the order because the setup is the same. And for the frequencies of each, it's just the inverse. Hope this helps someone out there.



"To laugh often and much; to win the respect of intelligent people and the affection of children...to leave the world a better place...to know even one life has breathed easier because you have lived. This is to have succeeded."
-Ralph Waldo Emerson
 
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Just joined the thread. Seems to be a lot of great information exchange and support. I'm a first time MCAT taker and my plan has been:

First 10 weeks:
Exclusively using Examkracker complete package, including the 1001 series and VR 101 passages. I'm currently in week 4.

Last 2-3 weeks:
Take off work and complete as many AAMC MCATs as possible (hopefully all of them). I'm thinking 1 exam/day. Hope this isn't an unrealistic or counterproductive method.

On average, I study 4-5 hours a day, at least 6 days a week. I work full-time, teach part-time, and am taking 12 credit hours at school. So far, I've stayed on track (thanks to the support from my fianc&#233😉. Hoping the trend continues.

Would be grateful for any suggestions. Thanks for all of the great information in this thread. 2 more months!!!
 
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ihb said:
Just joined the thread. Seems to be a lot of great information exchange and support. I'm a first time MCAT taker and my plan has been:
Click to expand...
Welcome 😀

ihb said:
First 10 weeks:
Exclusively using Examkracker complete package, including the 1001 series and VR 101 passages. I'm currently in week 4.
Click to expand...
sounds good, and also sounds similar to SN2ED

ihb said:
Last 2-3 weeks:
Take off work and complete as many AAMC MCATs as possible (hopefully all of them). I'm thinking 1 exam/day. Hope this isn't an unrealistic or counterproductive method.

On average, I study 4-5 hours a day, at least 6 days a week. I work full-time, teach part-time, and am taking 12 credit hours at school. So far, I've stayed on track (thanks to the support from my fiancé). Hoping the trend continues.

Would be grateful for any suggestions. Thanks for all of the great information in this thread. 2 more months!!!
Click to expand...

ideally i say 1 test every 2 or 3 days (or more if you have the time) because you want to review what you missed and do extra problems in weak spots. if you're doing 1 a day you may not be able to do all that. I know i was exhausted after a test so it's sort of tough to keep that energy level up, even if you are running on adrenaline.
 
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Hey anyone gotta famous way of remembering the sin and cos values? All i can ever remember is that sin 0 is 0...and cos 0 is 1. I was in physics doing practice problems and my professor pulled out a calculator and in my head i was like hey, you don't need a calculator for this big guy...but i forgot my sin and cos values 🙁 thanks again!

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Jr MD said:
Hey anyone gotta famous way of remembering the sin and cos values? All i can ever remember is that sin 0 is 0...and cos 0 is 1. I was in physics doing practice problems and my professor pulled out a calculator and in my head i was like hey, you don't need a calculator for this big guy...but i forgot my sin and cos values 🙁 thanks again!

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Click to expand...

I just picture the unit circle and know that the x,y coordinates of points on the circle are cos,sin of the angle.
 
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Remember this chart. It's simple to memorize:

1.) The sine values are the reverse of cosine values. So, the number under the radical is 0, 1, 2, 3, and 4 from top to bottom for sine and bottom to top for cosine.

2.) All are divided by 2

3.) Remember order of angles: 0, 30, 45, 60, and 90.

4.) Memorize that sqrt of 2 is ~1.4 and the sqrt of 3 is ~ 1.7.

From here, it's simple math:

i.e., sqrt 2 / 2 is like saying 1.4/2, or about 3/4, which is around 0.75. In this case, the answer is 0.7, but this is probably sufficiently close for MCAT approximation.



MCAT on 3/23 followed by the relaxation of medical school applications (and hopefully interviews)!
 
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Or you could just understand why they oppose each other like that as they curve around the unit circle in the first quadrant.

But hey, if memorization works then whatever. I'm just saying if you can't remember one in particular and you just have them memorized you're left without a way to figure it out.
 
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I'm horrible at trig and don't enjoy geometry, so this is the only way I knew. You're right, if I don't remember, i'm going to be lost. I'd love to learn the method you use. Thanks!
 
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See yesterday's Fact here

Today's fact concerns acid-base chemistry! (This is a weird one)

Bronsted-Lowry acid-base strength is based on acid ionization or base hydrolysis in water, but is independent of solubility.

That's right, the solubility of the compound, the extent tow which it dissociates in water, does not affect its strength as an acid or base. How is this possible? Because dissociation in water is a function of a compound's Ksp, not its Ka or Kb.

Bases like NaOH are infinitely soluble in water, they will almost never precipitate out. On the other hand, some bases show limited solubility in water. Calcium hydroxide is a great example. Even though not all of a given amount of solid Ca(OH)2 dumped in water will dissociate, 100% of what does dissociate undergoes hydrolysis. This makes sense when you consider that any freed hydroxide ions from dissociated Ca(OH)2 will naturally be highly reactive with H2O molecule they come in contact with.
 
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ihb said:
I'm horrible at trig and don't enjoy geometry, so this is the only way I knew. You're right, if I don't remember, i'm going to be lost. I'd love to learn the method you use. Thanks!
Click to expand...

Understand this picture:

images


And then look at the first quadrant in the unit circle (the upper right quadrant):

480px-Unit_circle_angles.svg.png


See how, as the line curves from (1,0) up to (0,1) the y-value increases from zero to 1? This means the sin of the angle starts at zero and increases to one. And the x-value decreasing from 1 to 0? This means the cos of the angle starts at 1 and decreases to zero.

You already know the angle measurements that are important (0, 30, 45, 60, 90 degrees) and if you understand that these are the internal angles of the unit circle (they're the "t" value in the first picture) then you can memorize that:

1) All cos and sin values can be expressed as a sqrt(x)/2
2) The value of x in that fraction changes in whole integer steps

Then, you can remember that cos and sin each start and end at 1 and 0 values, meaning they begin at sqrt(4)/2 and sqrt(0)/2, and increase or decrease in steps of 1 in the radical.
 
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cool! Now also...does any bidy understand the concept behind the pKas of amino acids? Im talking about passage 13 in TBR Acid base chapter ig Gchem question 89. I've been trying to understand this for an hour now :/... I understand that at a pH of 7 the carboxylic terminal and side chain are deprotonated and the amino terminal its protonated but in what order does this occur? Which one is pKa1 2 and 3? Sorry for ask the questions :/

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Haven't done that one yet! Sorry Jr.

Also, back to the log strategy thing. I just do what TBR demonstrates along with the log trick of 3's. If you have TBR's books (which you do) then you're good.
 
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Jr MD said:
cool! Now also...does any bidy understand the concept behind the pKas of amino acids? Im talking about passage 13 in TBR Acid base chapter ig Gchem question 89. I've been trying to understand this for an hour now :/... I understand that at a pH of 7 the carboxylic terminal and side chain are deprotonated and the amino terminal its protonated but in what order does this occur? Which one is pKa1 2 and 3? Sorry for ask the questions :/

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Click to expand...

i can help out on this one. this is one of the few chapters i feel really comfortable with.
they tell you that the pka for the carboxyl terminal is between 1.8 and 2.6, the pka for the side chain is 6.05 and the pka for the amino terminals are roughly between 8.8 and 10.6 for the amino acids. another thing you need to know which is in passage is the formula they include with pka+ pbk =14.

when the pH> pka, then that terminal (idk what word to use to describe it better) is deprotonated. for example, when the ph is greater than 2.6, the carboxyl terminal is in its deprotonated form. so they give you a ph of 7 which is greater than the phs of both the carboxyl terminal and the side chain of hisitidine which means that both will be in their deprotonated states and therefore, you would use the kb values for them. so instead of using pka1 of roughly 2, you'd look for pkb3 of (14-pka1) because the first proton lost is the last one picked up. for histidine, it follows the same trend. because it is deprotonated, you use the pkb value which would be 14-pka2=7.95. however, for the amino terminal, because the ph is 7 and is less than the pka, it remains protonated and for the amino terminal, you would stick with the original pka3 which is 9.15. hope this makes sense. feel free to ask for clarification on anything.
 
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I just took AAMC4, so f***ing giddy right now. 13/11/13!!! time for a beer 🙂

Good luck everyone- there's hope yet!!
 
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NuttyEngDude said:
went to class today then been studying since i got home, i feel like this:

8388044041_73ce37636d.jpg
Click to expand...

Lmao Bro me too...just finished the chapter on hydrocarbons. Finally done with the Ochem 1 book...sigh...gotta keep going! The only thing I fear is that on test day all my work won't show 🙁

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Quick question about EK VR 101:

I'm on my 3rd VR exam. I've scored a 9, 9, and 11, respectively. The problem is that I'm having trouble with time.

On test #1, I went over by 15 minutes. I obviously wasn't very prepared.

On test #2, I was over time by about 2.5 minutes.

On test #3, I was over time by 6 minutes. I did have multiple interruptions during the test, but by best estimation, I could probably only attribute 2-3 minutes to interruptions. Even then, I would still be 2-3 minutes over the time limit.

I'm wondering how everyone else is fairing with timing versus scores. If you're doing well with scores and staying within the time, how do you read the passages? Do you skim? Reread parts of the passage or question? Ever refer back to the passage? How did you change your strategy to improve timing?

Thanks!
 
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Here's a GTLO passage for you guys:

Patch-clamp technique involves recording the electrical activity individual cells with a glass micropipette electrode. The open-ended micropipette is filled with an electrolytic solution containing a thin wire electrode, and is inserted just through the cell membrane. Various cellular events can be detected using the current recordings from a patch-clamp apparatus.

1. In relation to the cell cytoplasm, the solution in the micropipette is most likely:

A. Hypotonic
B. Isotonic
C. Acidic
D. Basic

2. When a neuron under recording is stimulated with an appropriate neurotransmitter, initiation of an action potential is observed on the recording. However, when the neurotransmitter is gradually applied through slowly increasing concentration, no action potential is observed. Voltmeter recording across the membrane shows a membrane potential above the threshold potential for the neuron. This is an example of:

A. Inhibitory post-synaptic potential
B. Homeostasis
C. Accommodation
D. Fatigue

3. Loss of which of the following cytoskeletal elements would have the greatest effect on neural fatigue?

A. Microtubules
B. Microfilaments
C. Actin filaments
D. Intermediate filaments

4. Saltatory conduction in the peripheral nervous system would be most impaired by the widespread death of which of the following?

A. Microglia
B. Oligodendrocytes
C. Schwann cells
D. Neurons

5. Which of the following may act as integrating centers in reflex arcs?

I. Brain
II. Spinal cord
III. Ganglia

A. I
B. II
C. I and II
D. II and III
 
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gettheleadout said:
Here's a GTLO passage for you guys:

Patch-clamp technique involves recording the electrical activity individual cells with a glass micropipette electrode. The open-ended micropipette is filled with an electrolytic solution containing a thin wire electrode, and is inserted just through the cell membrane. Various cellular events can be detected using the current recordings from a patch-clamp apparatus.

1. In relation to the cell cytoplasm, the solution in the micropipette is most likely:

A. Hypotonic
B. Isotonic
C. Acidic
D. Basic

2. When a neuron under recording is stimulated with an appropriate neurotransmitter, initiation of an action potential is observed on the recording. However, when the neurotransmitter is gradually applied through slowly increasing concentration, no action potential is observed. Voltmeter recording across the membrane shows a membrane potential above the threshold potential for the neuron. This is an example of:

A. Inhibitory post-synaptic potential
B. Homeostasis
C. Accommodation
D. Fatigue

3. Loss of which of the following cytoskeletal elements would have the greatest effect on neural fatigue?

A. Microtubules
B. Microfilaments
C. Actin filaments
D. Intermediate filaments

4. Saltatory conduction in the peripheral nervous system would be most impaired by the widespread death of which of the following?

A. Microglia
B. Oligodendrocytes
C. Schwann cells
D. Neurons

5. Which of the following may act as integrating centers in reflex arcs?

I. Brain
II. Spinal cord
III. Ganglia

A. I
B. II
C. I and II
D. II and III
Click to expand...

My answers below:
1. b
2. d
3. a
4. c
5. c
 
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Charles Darwin said:
I had the same responses but with a different guess for #3. 😀
Click to expand...

awesome, bio and ochem are my weakest subjects 😛

edit: taking a break from mcat studies to watch the online kaplan class on professionalism... it's interesting, any of you kaplan guys watching this?
 
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NuttyEngDude said:
my answers for GTLO passage:

1. B
2. C
3. C (guess)
4. C
5. D

edit: thanks a lot for making these questions 🙂
Click to expand...

Why did you pick D for number 5? I thought reflex arcs had to go integrate somewhere in the CNS? I'm not sure though, bio is my weakest subject lol
 
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My answers and explanations for choices:

1.) B - Question states that the micropipette is "open-ended," inferring that molecules are free to diffuse, resulting in isotonicity.

2.) C - Term knowledge

3.) C - Really, I guess here. Actin filaments are involved in muscle movement, repeated movement results in depletion of NTM supply, thus fatigue?

4.) C - Schwann cells are responsible for myelin in the PNS. Oligodendrocytes are responsible for myelin in the CNS.

5.) C - Brain and spinal cord can be involve in reflex arcs. Generally, however, most reflex arcs are limited to to the spinal cord using an interneuron.
 
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osprey099 said:
Why did you pick D for number 5? I thought reflex arcs had to go integrate somewhere in the CNS? I'm not sure though, bio is my weakest subject lol
Click to expand...

Hmm, I thought I read it somewhere, and my assumption is the ganglia has enough nerves bundled to make a responsive action. I tried to find stuff via google and this is all i can find:
http://forums.studentdoctor.net/showthread.php?t=974944

and this power point slide set from wsu.edu (attached)

edit: hmm ok it exceeded the file size limit. here's the link:
http://public.wsu.edu/~kkardong/Web of KVK_06b/COURSES/Biology 324/Nervous System2_B&W.pdf
 
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1. Choice B is best. The electrolytic solution in the micropipette should be isotonic to the interior of the cell. The pipette is open-ended, meaning that once inserted through the cell membrane, the solution will be contiguous with the cytosol. If the solution were significantly hypotonic, there would be an immediate influx of water from the pipette into the cell, risking rupture. The solution should be at physiological pH, there is no reason it need be acidic or basic.

2. Choice C is best. The effect of the neurotransmitter on the neuron must to create an excitatory post-synaptic potential, as action potential initiation was observed prior in the experiment, eliminating Choice A. Choice B is vague and not applicable to the question. Accommodation is defined as the lack of response to a stimulus above the normal threshold, in this case a membrane potential beyond the threshold potential. Accommodation occurs as the cell adjusts to the slow increase in stimulus intensity. Not enough information is given in the question stem to conclude that fatigue is occurring, eliminating Choice D.

3. Choice A is best. Neural (or synaptic) fatigue occurs when neurotransmitter is released from the synaptic bulb faster than it can be replenished in secretory vesicles. Neurotransmitters are synthesized in the body (soma) of the neuron, and transported by kinesin and dynein motor proteins down the axon to the synaptic bulb, a process called axonal or axoplasmic transport. These motor proteins "walk" down a scaffolding of microtubules within the axon. Loss of these microtubules would render axonal transport impossible, likely leading to rapid fatigue of the neuron. As a point of note, Choices B and C are the same thing; microfilaments are actin filaments.

4. Choice D is best. This question poses both oligodendrocytes and Schwann cells as possible choices, aiming to lure the tester into recognizing the peripheral nervous system cue in the stem and choosing C upon eliminating B. Death of Schwann cells would certainly lead to a decrease in myelination, but the myelin sheaths formed would still exist in place; little metabolism occurs within the layers of myelin themselves. As in demyelinating diseases, the exact mechanism of myelin breakdown is not known, but some saltatory conduction would occur as the preexisting myelin lingers. If neurons themselves were to die, there would be immediate loss of conductivity, saltatory or otherwise.

5. Choice C is best. Reflex arcs involve integrating centers, specific neurons and synapses within the CNS. Most integrating centers lie in the spinal cord, but a number involve cells in the brain, often the brainstem, as well. Ganglia are peripheral nervous system structures, and though they may be involved in the signal transduction pathway of autonomic reflex arcs, they do not function as integrating centers.
 
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NuttyEngDude said:
thanks GTLO!
Click to expand...
No problem!
osprey099 said:
Death of neurons.. dammit lol
Click to expand...
Haha yeah, no one got that one.
Charles Darwin said:
Okay_guy.jpg

Back to the books I go...
Click to expand...

Don't sweat it man. But yeah, you should know that microtubules provide the "tracks" for axonal transport, and why such transport occurs. Leave stuff like antero- and retrograde and fast/slow transport for a passage.
Entadus said:
+1 😛

I didn't even read answer choice D! I stopped reading at C and picked that.... Very tricky GTLO :naughty:
Click to expand...
Haha, I've done that before and that's partially why I ordered the answers that way. On a test that always asks for the BEST answer, you need to read EVERY answer choice carefully. I'm as guilty of not following that rule as anyone else, but any way to drill that in seems like progress to me lol.
 
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gettheleadout said:
Haha, I've done that before and that's partially why I ordered the answers that way. On a test that always asks for the BEST answer, you need to read EVERY answer choice carefully. I'm as guilty of not following that rule as anyone else, but any way to drill that in seems like progress to me lol.
Click to expand...

Something I need to get better at 🙂

good passage. Someone else want to make the next?
 
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Actin filaments are involved in exocytosis and endocytosis so I don't know if you could say they're less important than microtubules in stopping fatigue.

Also for 1 I can't picture the setup you're describing. Are you saying a hypotonic solution would draw the contents out of your micropipette? Ones I have used keep their solution in due to a difference in pressures on either side of the liquid and wouldn't be affected by osmolarity, but you may be describing something different. If the sol'n in the pipette is more elctrolytic than the cytosol than it would have to be hypertonic, but I don't know if that would be necessary for the setup you described.
 
Last edited:
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GLUT4 expression is decreased in adipocytes in nearly all insulin resistant states in humans and rodents, but the mechanism by which this contributes to systemic insulin resistance has not been clear. Researchers hypothesize that elevated serum RBP4 might be a mechanistic link by which downregulation of GLUT4 in adipocytes contributes to the development or worsening of systemic insulin resistance. The results of this study show that RBP4 elevation is a widespread abnormality in insulin-resistant states of various etiologies. Serum levels and/or urinary excretion of RBP4 have been reported to be elevated in humans with type 2 diabetes.

In the figure (attached), different groups of mice were injected with insulin to test the Rbp4's effect on insulin activity in muscle cells and liver cells.

(I had a hard time trying to squeeze the figure into the SDN attachment dimensions so it's pretty small but you can zoom in hopefully)

QUESTIONS:
1. After a large meal, which of the following hormones would be expected to be in high levels in the blood?
a. Glucagon
b. Cortisol
c. Insulin
d. Epinephrine

2. Which of the following is a likely consequence of someone with low insulin sensitivity?
a. Increased secretion of glucagon
b. Increased urinary output
c. Stomach ulcers
d. Increased blood pH

3. Based on figure 1, which of the following is true?
a. Rbp4 has a causal role in insulin resistance in hepatocytes only
b. Rbp4 has a causal role in insulin resistance in muscle cells only
c. Rbp4 has a causal role in both hepatocytes and muscle cells
d. Rbp4 does not have a causal role in either hepatocytes or muscle cells.

4. Rosiglitazone is an anti-diabetic agent that improves insulin sensitivity. Rosiglitazone's effect is most likely seen in:
a. Liver cells
b. Muscle cells
c. Both liver and muscle cells
d. Neither liver nor muscle cells

5. Based on the information in the passage, what is the expected level of Rbp4 mRNA in liver cells of Glut4-/- mice, compared to a wild type control group of mice?
a. Greater Rbp4 mRNA level than control
b. Smaller Rbp4 mRNA level than control
c. Same Rbp4 mRNA level as control

Have fun 🙂
 

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