PCAT PCAT Certifications PCAT Questions & Answers

• Question 271:

  Which of the following is involved in hearing?

  A. microvilli

  B. cilia

  C. hair follicles

  D. hair cells

  Correct Answer: D

  Hair cells lining the basilar membrane utilize mechanotransduction to detect, to amplify, and to convert mechanical sound waves into electrical signals. The resulting action potential then passes through the cochlear nerve to reach the brain.

• Question 272:

  For vision, ___ must be converted to _____ in the cells of the retina.

  A. vitamin C, retinal

  B. vitamin E, biotin

  C. vitamin A, retinal

  D. vitamin A, biotin

  Correct Answer: C

  Vitamin A is a precursor of retinal, which is the chemical compound that enables animals to see. Biotin is associated with vitamin B. Carrots are known to be good for vision because they are high in vitamin A.

• Question 273:

  What results in extra or fewer chromosomes in a cell?

  A. nondisjunction

  B. double replication

  C. double cytokinesis

  D. epistasis

  Correct Answer: A

  Nondisjunction is when chromosomes do NOT separate during anaphase. Consequently, the resulting cells display an unequal sharing of chromosomes, with some cells having too many, and others having too few.

• Question 274:

  Which is not a function of immunoglobins?

  A. coagulation

  B. assist in phagocytosis

  C. attack pathogens

  D. labeling of pathogens

  Correct Answer: C

  Antibodies or immunoglobins perform all of the functions except for directly attacking pathogens. Leukocytes, or white blood cells, are responsible for attacking pathogens.

• Question 275:

  A virulent phage is one which infects via:

  A. the lysogenic cycle

  B. phagocytosis

  C. immunoglobins

  D. the lytic cycle

  Correct Answer: D

  Virulent phages use the lytic cycle to infect an organism. The lytic cycle is the process by which a phage DNA replicates itself via the host cell before causing the cell to lyse and release all of the phage's replications.

• Question 276:

  Which of the following is not secreted by the hypothalamus?

  A. glucocorticoids

  B. GnRH

  C. Dopamine

  D. GHIH

  Correct Answer: A

  Glucocorticoids are steroids synthesized and secreted by the adrenal cortex not the hypothalamus.

• Question 277:

  Which of the following does hemoglobin bond most strongly with?

  A. oxygen

  B. carbon dioxide

  C. carbon monoxide

  D. hydrogen

  Correct Answer: C

  Hemoglobin bonds most strongly with carbon monoxide as a result of the interaction of the orbitals of the hemoglobin and the carbon monoxide molecule. The carbon forms an ionic bond with the hemoglobin's iron, and because of the joint configuration, the iron is able to donate additional electrons to the carbon monoxide.

• Question 278:

  Which of the following decompose disaccharides into monosaccharides?

  A. salivary amylase

  B. pancreatic enzymes

  C. gastrin

  D. brush border enzymes

  Correct Answer: D

  Disaccharides such as sucrose, maltose, and lactose, etc., are broken down further into monosaccharides (primarily glucose) in the small intestine by way of brush border enzymes lining microvilli of the small intestine.

• Question 279:

  The T-tubules transmit an action potential, causing the opening of ____ channels in the ____.

  A. Na+, Sarcoplasm

  B. Ca2+, Sarcoplasmic Reticulum

  C. Na+, Sarcoplasmic Reticulum

  D. Ca2+, Sarcoplasm

  Correct Answer: B

  The T-tubules conduct action potentials that cause channels to open on the surface of the sarcoplasmic reticulum. The opening of these channels results in a release of Ca2+ into the sarcoplasm of the muscle fiber.

• Question 280:

  Which of the following yields the least ATP directly?

  A. TCA cycle

  B. oxidative phosphorylation

  C. glycolysis

  D. Beta Oxidation

  Correct Answer: A

  The TCA cycle yields 2 GTPs (molecules that can be converted to ATP but are not ATP themselves), oxidative phosphorylation, which includes the ETC, can yield from 32 to 34 ATP. Glycolysis yields 2 ATP. Beta oxidation yields a range over 100 ATP that depends on the length of the fatty acid being degraded.