Admission Tests Admission Tests Certifications PCAT Questions & Answers

• Question 261:

  Energy for ATP synthesis is produced primarily by: A. NADH

  B. proton gradient

  C. ATP synthase

  D. Na+

  Correct Answer: B

  Proton pumps located along the inner mitochondrial membrane enable the passage of H+ across a

  concentration gradient. These protons pass through ATP synthase in which an axel rotates to combine

  phosphate with ADP to form ATP.

  Without the proton gradient, ATP synthase could not create ATP.

• Question 262:

  Blood flows from the mitral valve to the:

  A. left atrium

  B. aorta

  C. right ventricle

  D. left ventricle

  Correct Answer: D

  The left atrium connects to the left ventricle by way of the mitral valve. The left ventricle connects to the aorta by way of the aortic valve. Blood flows from the pulmonary veins into the left atrium and through the mitral valve (bicuspid valve), to the left ventricle then out through the aorta.

• Question 263:

  Which of the following statements regarding energy production is true?

  A. There is a net total of 4 ATP produced in glycolysis.

  B. The GTP made in the TCA cycle does not become ATP.

  C. The cell requires energy to move NADH into the mitochondria.

  D. The net gain of ATP from each NADH is 2.

  Correct Answer: C

  Transport of the NADH into the mitochondria in most cases requires 1 ATP. This is the reason that prokaryotes often have a higher yield of ATP per glucose when compared to eukaryotes. Usually 38 ATP are produced per glucose for prokaryotes, and 36 per glucose for eukaryotes.

• Question 264:

  Which cells make up the insulated wrapping on axons?

  A. Schwann cells

  B. astrocytes

  C. microglia

  D. macrocytes

  Correct Answer: A

  Axons are surrounded by insulating cells called Schwann cells. This insulation enables action potentials to travel rapidly throughout the nervous system.

• Question 265:

  Which of the following corresponds to the coding strand of the following mRNA?

  5'-GUAACGUCA- 3'

  A. 5'-GTAACGTCA-3'

  B. 5'-CATTGCAGT-3'

  C. 5'-ACUGCAAUG- 3'

  D. 5'-TGACGTTAC- 3'

  Correct Answer: A

  The coding strand is NOT the complementary strand; it is the strand of DNA which is complementary to the strand from which mRNA is made. The coding strand will have the same sequence of bases as the produced RNA transcript except with thymine instead of uracil. A useful mnemonic for remembering the nucleotide bases in DNA and RNA is "GCAT PuPy" and "GCAU PuPy." GCAT/U stand for guanine, cytosine, adenine, thymine, and uracil, and "Pu" and "Py" represent purine and pyrimidine, respectively.

• Question 266:

  Which of the following lists the correct taxonomic order from most inclusive to least inclusive?

  A. Kingdom, Order, Class, Species

  B. Order, Family, Genus, Phylum

  C. Order, Family, Genus, Species

  D. Phylum, Order, Species, Genus

  Correct Answer: C

  Kingdom, Phylum, Class, Order, Family, Genus, Species. The mnemonic, "King Philip Came Over For Great Spaghetti," is very useful for remembering the taxonomic order from most inclusive to least inclusive.

• Question 267:

  In which non-membranous compartment are ribosomes made in a eukaryotic cell?

  A. nucleus

  B. rough ER

  C. nucleolus

  D. cytoplasm

  Correct Answer: C

  Ribosomes are manufactured inside of the nucleolus. RNA polymerases I and III work together to create ribosomes from rRNA and proteins.

• Question 268:

  Which of the following occurs as a rise in intraocular pressure?

  A. inflammation of the cornea

  B. glaucoma

  C. cataract

  D. diabetic retinopathy

  Correct Answer: B

  Intraocular pressure (IOP) poses the greatest risk of causing glaucoma. A reduction in the flow and drainage of aqueous humor leads to a rise in IOP. The built-up pressure eventually results in glaucoma and optic nerve damage.

• Question 269:

  Which of the following will result if there is a drop-in blood pressure?

  A. formation of glucose

  B. secretion of insulin

  C. secretion of EPO

  D. secretion of ANP

  Correct Answer: C

  A drop-in blood pressure causes the renal cortex of the kidney to secrete EPO (erythropoietin) in an effort to increase the blood pressure by increasing the synthesis of red blood cells. EPO is a necessary precursor for red blood cell production to take place.

• Question 270:

  Which is not active in bone resorption?

  A. osteoblasts

  B. osteoclasts

  C. nephrons

  D. small intestine

  Correct Answer: A

  Bone resorption, the decomposition of bone for absorption of minerals, including calcium, directly involves osteoclasts. Nephrons and the small intestine both absorb released Ca2+. Osteoblasts function to construct, not decompose, bones.