Free Practice Test Prep MCAT Exam Questions 2025

Stay ahead with 100% Free Medical College Admission Test: Verbal Reasoning, Biological Sciences, Physical Sciences, Writing Sample MCAT Dumps Practice Questions

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Total 815 Questions | Updated On: Mar 25, 2025
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Question 1

Which of the following molecules will stop being produced first when oxygen is no longer supplied to the cell? 


Section: Biological Sciences 


Answer: C
Question 2

Which of the following will halve the magnitude of the electrostatic force of attraction between two charged
particles?

Section: Physical Sciences 


Answer: C
Question 3

All of the following are true regarding the function of neurons EXCEPT:

Section: Biological Sciences 


Answer: C
Question 4

Synthetic dyes constitute a commercially significant area of organic chemistry. The color producing properties
of these compounds are the result of highly delocalized electron systems giving rise to electronic transitions
whose absorptions occur in the visible region. Most commercially useful dyes can be classified as one of three
types – anthraquinones, azo dyes, or triarylmethyl salts. Examples of each type are illustrated in Figure 1.
MCAT-patt-4-page313-image105
Figure 1
In order for a dye to be useful in the fabric industry, it must have sufficient affinity for the polymeric fibers of
which the material is composed; the dye must not only impart a color to the fabric, but must also do so in a
relatively permanent manner (color fastness). Proper design of synthetic polymers requires the placement of
acidic or basic side chains along the polymer backbone such that binding sites are available for dying. Similarly,
dyes must be produced not only with the appropriate color-producing structure, but also with an affinity for the
fabric in question. The structural units of several common synthetic fibers are shown in Figure 2.
MCAT-patt-4-page313-image104
Figure 2
Dacron belongs to which of the following general classifications?

Section: Biological Sciences 


Answer: B
Question 5

Compounds containing a hydroxyl group attached to a benzene ring are called phenols. Derivatives of phenols,
such as naphthols and phenanthrols, have chemical properties similar to those of phenols, as do most of the
many naturally-occurring substituted phenols. Like other alcohols, phenols have higher boiling points than
hydrocarbons of similar molecular weight. Like carboxylic acids, phenols are more acidic than their alcohol
counterparts. Phenols undergo a number of different reactions; both their hydroxyl groups and their benzene
rings are highly reactive. A number of chemical tests can be used to distinguish phenols from alcohols and
carboxylic acids.
MCAT-part-3-page300-image70
Thymol, a naturally occurring phenol, is an effective disinfectant that is obtained from thyme oil. Thymol can
also be synthesized from m-cresol, as shown in Reaction A below. Thymol can then be converted to menthol,
another naturally-occurring organic compound; this conversion is shown in Reaction B.
Reaction A
MCAT-part-3-page300-image69
Reaction B
MCAT-part-3-page300-image68
Comparing the Ka values for cyclohexanol (Ka = 10−13) and phenol (Ka = 1.3 × 10−10) reveals that phenol is more
acidic than cyclohexanol. Which of the following explain(s) the acidity of phenol?
I. The exceptionally strong hydrogen bonding possible with phenol facilitates the loss of a proton, making it
more acidic than cyclohexanol.
II. Phenol’s conjugate base, phenoxide, is stabilized by resonance to a greater extent than phenol itself.
III. The negative charge of the oxygen atom on the phenoxide ion is delocalized over the benzene ring.

Section: Biological Sciences 


Answer: C
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Total 815 Questions | Updated On: Mar 25, 2025
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