Cisco
CompTIA
ISC
EC-Council
EXIN
Fortinet
ITIL
Juniper
Microsoft
VMware
Avaya
SAP
Google
NVIDIA
Salesforce
Amazon
Palo Alto Networks
ISC2
Splunk
ServiceNow
All Vendors
  2. Home
  3. Exams
  4. Test Prep
  5. MCAT Test

Test Prep MCAT Test Exam
Medical College Admission Test: Verbal Reasoning, Biological Sciences, Physical Sciences, Writing Sample (Page 27 )

Updated On: 30-Jan-2026
Page 27 of 164
PDF with 811 Questions

All of the following are example of sensory, or neural, adaptation EXCEPT:

  1. After putting on a shirt, you eventually no longer feel the sensation of the fabric on your back.
  2. After first walking into a crowded room, you no longer are distracted by the buzz of conversation around you.
  3. After first walking outside on a sunny day, you no longer are blinded by the initial brightness of the light.
  4. After first walking into an anatomy lab, you no longer notice the smell of formaldehyde.

Answer(s): C

Explanation:

Choices A, B, and D are all examples of sensory adaptation occurring the due to the brain's adaptation to a constant neural stimulus. Choice C, on the other hand, is due to the contraction of the iris, which in narrows the pupil and restricts the amount of light being received by our retinA. It is therefore not an example of our brain's adaptation to a constant neural stimulus, but a muscular contraction that changes the amount of stimulus.



The human kidney can be damaged from a number of causes resulting in a patient's inability to filter toxins (i.e. urea) from the body which could result in death. Complete kidney failure is usually first treated with dialysis which "cleans" the blood.

Dialysis. The "dialyzer" is a glass container that has 3 main components: (1) blood percolating Figure 1:
through to be cleaned; (2) a dividing membrane; and (3) the dialysate. The latter is liquid containing chemicals used to draw fluids and toxins out of the bloodstream and supply electrolytes and other chemicals to the bloodstream. (kidney.niddk.nih.gov)
Considering the information provided, which of the following is NOT consistent with the process of dialysis?

  1. The membrane in the dialyzer separating the dialysate and the blood must be semipermeable.
  2. The concentration of toxins in the dialysate must increase during dialysis.
  3. The concentration of glucose and vital minerals in the dialysate must be similar to that of the patient's blood.
  4. Excessive minerals and toxins cross the membrane in the dialyzer by osmosis.

Answer(s): D

Explanation:

On the Surface: Dialysis only refers to the transfer of the solute (diffusion), while the transfer of the solvent is called osmosis.
Going Deeper: Diffusion is the movement of a substance down its concentration gradient (from a region of high concentration to one of lower concentration). This is the process that must be occurring in the dialyzer to remove toxins from the blood (because the dialysate, logically, would have no toxins so the toxins defuse out of the blood into the dialysate). Note that vital substances in the blood should be kept in the blood: options would include having a dialysate with the same concentration of those substances (so they don't diffuse out of the blood) or by adjusting the permeability of the membrane.
Osmosis is the movement of a solvent across a semi-permeable membrane from a region of low solute concentration to a region of high solute concentration. In Biology and Biochemistry, that solvent is, of course, water. In this context, the easier way to imagine osmosis is that it is simply the diffusion of water across a semi- permeable membrane from a region of high water concentration (i.e. low solute concentration) to a region of low water concentration (i.e. high solute concentration).
So, in summary, osmosis deals with how much water passes through the membrane, while dialysis deals with what type of solute (i.e., sodium, protein, glucose) passes through by simple diffusion.
E. B. Notice the link between diffusion and osmosis and the Second Law of Thermodynamics (Physics). All spontaneous change leads to an increase in the entropy (randomness) of the universe. Of course, biological systems exist because processes which increase entropy can be coupled with processes which increase order, as long as the overall (net) entropy of the universe increases.



Which of the following phases are common to cells undergoing meiosis and mitosis?
I). G0 phase
II). G2 phase
III). S phase

  1. I only
  2. I and II only
  3. II and III only
  4. I, II, and III

Answer(s): C

Explanation:

This question asks the examinee to determine a phase within the cell life cycle that is common to both mitotic- dividing cells and meiotic-dividing cells. The cell cycle is composed of interphase and M phase. In mitotic- dividing cells, interphase includes G1 phase, S phase, G2 phase, and in highly specialized cells, such as neurons, a G0 phase. Similarly, meiotic-dividing cells include interphase and M phase, but germ cells do not exist in growth arrest phase (G0). Thus, II and III are correct making answer choice C the best answer.



Which structure shows two amino acids linked by 1 peptide bond?





Answer(s): D

Explanation:

Amino acids are joined by a peptide bond: 1) the leading amino acid has a primary amine group to the left, 2) the peptide bond has a carbonyl group immediately following the first amino acid side chain, 3) bonded to a secondary amine leading the second amino acid side chain, and 4) the second amino acid finishes with a carboxylic acid group. Choice D is correct.



A segment of DNA from a lab mouse is determined to be 5 ­ GGATCCTCATG ­ 3.
Which of the following DNA segments would be the result of this original DNA sequence experiencing both a point mutation and a deletion?

  1. 5 ­ GCATCCTCATG ­ 3
  2. 5 ­ TGATCCCAG ­ 3
  3. 5 ­ GGTCCTCATC ­ 3
  4. 5 ­ GGATCCATG ­ 3

Answer(s): C

Explanation:

A point mutation is one in which a single DNA base has be replaced by another and a deletion in one in which a single DNA base has been deleted. The question asks us to look for an answer choice that has had both a point mutation and a deletion. Only choice (C) matches these requirements.
A, D: Neither (A) nor (D) has had any deletions at all ­ the length of the DNA chain is unchanged. B: Two deletions have occurred as well as a point mutation. Both the 7th and 10th nucleotide are missing (both T).



Viewing page 27 of 164
Viewing questions 131 - 135 out of 811 questions



Post your Comments and Discuss Test Prep MCAT Test exam prep with other Community members:

Join the MCAT Test Discussion