Admission Tests Admission Tests Certifications PCAT Questions & Answers

• Question 231:

  Leaves have parallel veins:

  A. Monocots

  B. Nonvascular plants

  C. Gymnosperms

  D. Dicots

  E. Angiosperms

  Correct Answer: A

  Monocots differ from dicots in that they have one cotyledon, or embryonic leaf in their embryos. They also have parallel veination, fibrous roots, petals in multiples of three, and a random arrangement of vascular bundles in their stems.

• Question 232:

  In photosynthesis, high-energy electrons move through electron transport chains to produce ATP and NADPH. Which of the following provides the energy to create high energy electrons?

  A. O2

  B. Light

  C. Water

  D. NADP+

  E. NADH

  Correct Answer: B

  Electrons trapped by the chlorophyll P680 molecule in photosystem II are energized by light. They are then transferred to electron acceptors in an electron transport chain.

• Question 233:

  Which of the following molecules is thought to have acted as the first enzyme in early life on earth?

  A. Protein

  B. RNA

  C. Triglycerides

  D. Phospholipids

  E. DNA

  Correct Answer: B

  Some RNA molecules in extant organisms have enzymatic activity; for example, the formation of peptide bonds on ribosomes is catalyzed by an RNA molecule. This and other information have led scientists to believe that the most likely molecules to first demonstrate enzymatic activity were RNA molecules.

• Question 234:

  The breakdown of a disaccharide releases energy which is stored as ATP. This is an example of a(n):

  A. Thermodynamic reaction

  B. Exothermic reaction

  C. Combination reaction

  D. Replacement reaction

  E. Endothermic reaction

  Correct Answer: B

  An exothermic reaction releases energy, whereas an endothermic reaction requires energy. The breakdown of a chemical compound is an example of a decomposition reaction (AB ?gt; A + B). A combination reaction (A + B ?gt; AB) is the reverse of a decomposition reaction, and a replacement (displacement) reaction is one where compound breaks apart and forms a new compound plus a free reactant (AB + C ?gt;AC + B or AB + CD ?gt; AD + CB).

• Question 235:

  What is the role of a nurse cell?

  A. secrete testosterone

  B. secrete sperm

  C. nurture maturing red blood cells

  D. activate sperm motility

  Correct Answer: C

  Nurse cells aid in the maturation of red blood cells. They are macrophages that absorb immature red blood cells and facilitate the growth of red blood cells.

• Question 236:

  Which of the following should be added to denature a protein all the way back to primary structure?

  A. reducing agent

  B. oxidizing agent

  C. water

  D. ether

  Correct Answer: A

  In order to denature proteins to their primary structure, a reducing agent is necessary to cleave the disulfide bonds in protein's secondary structure.

• Question 237:

  Which of the following is found in the plasma membrane of a cell?

  A. phospholipid

  B. glycoprotein

  C. cholesterol

  D. all of the above

  Correct Answer: D

  The plasma membrane of a cell is composed of a phospholipid bilayer, a double layer of lipids combined with phosphate groups. The hydrophilic nature of the phosphate heads and the hydrophobic nature of the lipids create a double-sided membrane with phosphates on both sides and lipids trapped between. Cholesterol and glycoprotein molecules are embedded inside the phospholipid bilayers.

• Question 238:

  Which of the following is NOT made by the pituitary gland?

  A. ACTH

  B. ADH

  C. FSH

  D. LH

  Correct Answer: B

  The list of hormones made by the pituitary gland can be recalled with the mnemonic FLATPOG, signifying: FSH, LH, ACTH, TSH, GH, MSH (melanocyte stimulating hormone), and prolactin. ADH is made by the hypothalamus and is only secreted by the posterior pituitary.

• Question 239:

  Where is the ETC located in bacteria?

  A. mitochondria

  B. Golgi apparatus

  C. peroxisome

  D. plasma membrane

  Correct Answer: D

  Eukaryotes house the ETC in their mitochondria, but bacteria, which are prokaryotic, do not possess mitochondria or organelles. The ETC in prokaryotic bacteria is located along the cell membrane.

• Question 240:

  An action potential would travel fastest in:

  A. unmyelinated, thick axon

  B. myelinated, thick axon

  C. unmyelinated, thin axon

  D. myelinated thin axon

  Correct Answer: B

  Axons are thin or thick bundles of nerve fibers. The thicker an axon is, the more quickly an action potential will travel through it. Additionally, a myelin sheath functions as an insulator that also facilitates the rapid transmission of an action potential.