So just how much time will you have? Lets take a look:

**Critical Analysis and Reasoning**

Number of Questions: 53

Section Time: 90 minutes

Minutes per Passage: 10

Minutes per Question: A little over 1.5 minutes

**Psychological, Sociological, and Biological Foundations of Behavior
**

Number of Questions:

Section Time: 95 minutes

Minutes per Passage: 8 minutes

Minutes per Question: About 1.5 minutes

**Biological Sciences
**

Number of Questions:

Section Time: 95 minutes

Minutes per Passage: 8 minutes

Minutes per Question: About 1.5 minutes

**Physical Sciences
**

Number of Questions:

Section Time: 95 minutes

Minutes per Passage: 8 minutes

Minutes per Question: About 1.5 minutes

*Next Step Test Preparation is the national leader in one-on-one MCAT tutoring. *

]]>

I. The ventricles of the brain

II. The sympathetic chain ganglia

III. The spinal canal

A) I only

B) I and II only

C) I and III only

D) I, II, and III

**Explanation**

The cerebrospinal fluid (CSF) is only found in the central nervous system (CNS). (I) and (III) are CSF-filled spaces within the CNS and are thus likely to contain endospores that spread through the CSF. Thus, the answer is (C). (II) is incorrect because the sympathetic chain ganglia are a part of the peripheral nervous system (PNS) and the CSF does not circulate through the PNS.

]]>

A) F_{1} = F_{2}

B) 2.5 F_{1} = F_{2}

C) F_{1} = 2.5 F_{2}

D) 2 F_{1} = F_{2}

**Explanation**

The equation for torque is given by:

τ = rF sin θ

where r is the distance between the fulcrum and the force, F is the applied force, and θ is the angle between the applied force and the lever arm.

For the boy, we can write the following equation:

τ_{1} = r_{1}F_{1}

The original question does not specify an angle for the boy. On the MCAT, if you’re not told otherwise then assume that θ is 90º in a torque problem and thus that sin θ is 1.

For the sister, we can write the following equation:

τ_{2} = r_{2}F_{2} sin θ_{2}

We are told that the length of the swing is 20% shorter and that she pushes with a force that is directed at 30º. Thus we may say that r_{2} = 0.8r_{1} and the equation becomes:

τ_{2} = 0.8r_{1}F_{2} sin 30

τ_{2} = 0.8r_{1}F_{2} (0.5)

τ_{2} = 0.4r_{1}F_{2}

Finally, we’re told that both torques are the same, so we may set them equal:

τ_{2} = 0.4r_{1}F_{2 }= τ_{1} = r_{1}F_{1}

0.4r_{1}F_{2 }= r_{1}F_{1}

0.4F_{2 }= F_{1}

So, the answer is:

**B) 2.5 F _{1} = F_{2 }**

I. The moles of titrant added to solution

II. The molarity of titrant added to solution

III. The temperature of the titrant

A) I only

B) II only

C) I and II only

D) I, II, and III

**Explanation**

The endpoint of a titration is an approximation of the equivalence point, and is usually indicated by a color change by the indicator. The equivalence point in a titration is when the moles of titrant added are equal to the moles of analyte in the beaker. Thus the only thing needed is (A). Often, the moles of titrant added is calculated using the volume and concentration.

II: While the molarity of titrant can be used to find the moles, it is not the molarity itself that matters, but rather the moles used.

III: Temperature is irrelevant in a titration.

]]>*Next Step Test Preparation provides one-on-one MCAT tutoring programs nationwide. *

A) wavelength

B) period

C) frequency

D) Planck’s constant

**Explanation**

The speed of a wave is given by the equation:

v = fλ

Since frequency and period are inverses of each other, the equation can also be expressed:

v = λ / T

Looking to these two equations, we can see that increasing the period, T, would decrease the speed of the wave, as the question asks. Thus, (B) is the correct answer.

A, C: Increasing either f or λ would increase the speed of the wave.

D: Planck’s constant is used to calculate the energy of a photon, not the speed of a wave.

]]>

A) Lead to death due to an inability of the cell to pass electrons to oxygen, thus stopping aerobic respiration and asphyxiating the cells.

B) Lead to death due to an inadequate supply of ADP to accept a phosphate group at the ATP synthase enzyme.

C) Have no effect as cells would switch which macronutrient they metabolize to circumvent the blocked biochemical pathway.

D) Increase the cell’s ATP production as negative feedback would cause the cell to up-regulate anaerobic pathways.

**Explanation**

The electron transport chain works by taking high-energy electrons from molecules like NADH and passing them through a series of enzymes, ultimately ending with oxygen as the final electron acceptor. If this chain is blocked, aerobic respiration would cease, killing the cell. Eukaryotic cells in humans cannot survive using only anaerobic respiration. Thus (A) is the right answer. Several poisons work in the manner described, most notably cyanide.

B: ADP is produced when cells use up ATP to carry out cell functions. Blocking the electron transport chain would have no effect on ADP’s immediate availability.

C: As discussed above, this poison would kill the person.

D: As discussed above, this poison would kill the person.

A) Adding a seed crystal of the purified substance that he is attempting isolate.

B) Cooling the solution very slowly.

C) Submerging the beaker in a cool water bath.

D) Scratching the side of the beaker.

**Explanation**

In a recrystallization procedure, a substance with impurities in dissolved in a small amount of hot solvent. The solvent is then very slowly cooled and the pure substance will crystallize out as its solubility decreases. To improve the outcome, the crytal needs a nucleation site to begin precipitating out. That can be provided either by scratching the wall of the beaker or by adding a seed crystal. Thus, (A) and (D) are incorrect.

If the solution is cooled too quickly, then both the pure substance and the contaminants may preciptate out all at once. Thus (B) is a way to improve the procedure, but (C), which would result in faster cooling would not solve the student’s problem. Thus (C) is the correct answer.

]]>

A) The student’s conclusion is correct.

B) The student’s conclusion is most likely correct, as a drug has effects both through its own action and through the action of its metabolites.

C) The student’s conclusion is most likely not correct, as caffeine has other metabolites which are direct antagonists of theophylline.

D) The student’s conclusion cannot be said to be correct or incorrect without more information about caffeine’s other metabolites and effects.

**Explanation**

The student isn’t entirely off-track here. Drugs have effects on the body both directly and through the action of their metabolites. However, the student has no information about what percent of caffeine is metabolized into theophylline, nor about what sort of dosages of caffeine or theophylline would be needed to effectively treat asthma. Thus (D) is the correct answer. In fact, only about 4% of caffeine is metabolized into theophylline, although theophylline is actually used as an asthma medication.

]]>

A) increase by a factor of 1.5

B) increase by a factor of 2.25

C) decrease by a factor of 1.5

D) decrease by a factor of √1.5

**Explanation**

The MCAT will expect you to know a handful of equations for capacitors. The three needed to solve this question are:

C = κε_{o}A / d

C = Q / V

PE = (½)QV

According to the first equation, we see that if the dielectric is removed, capacitance will decrease by a factor of 1.5.

According to the second equation, we see that a decreased capacitance can either be the result of a change in Q or a change in V. In this question, the AED is no longer connected to the battery, so there is no source of additional charges. Thus Q will remain the same and V will increase by a factor of 1.5

Finally, by the third equation we see that if V is increased by a factor of 1.5, the potential energy will increase by a factor of 1.5. Thus (A) is the correct answer.

]]>