21. Identify the incorrect statement regarding the complex interactions within the gut-brain axis:
(A) Short-chain fatty acids produced by gut microbiota can influence brain chemistry and behavior.
(B) The gut-brain axis communicates through the central nervous system and the body's hormonal responses but does not involve immune responses.
(C) Dysbiosis in the gut microbiota is linked to neurological and psychiatric disorders, such as depression and anxiety.
(D) Gut microbiota can influence the epigenetic regulation of genes in the central nervous system, impacting neural development and function.
(E) The gut-brain axis involves bidirectional communication, where not only does the gut influence brain function, but the brain also significantly affects gut microbiota composition and function.

17. What is the primary factor enabling the rapid conduction of action potentials in the giant axons of squids? (A) Myelination. (B) Low threshold. (C) Increased sodium channels. (D) Multiple axons. (E) Large diameter.

18. Which receptor directly mediates the transmission of nerve impulses at the neuromuscular junction? (A) Nicotinic receptor. (B) Muscarinic receptor. (C) α Adrenergic receptor. (D) β Adrenergic receptor. (E) Orexin receptor.

19. What are the two neurohormones primarily released by magnocellular neurosecretory cells at the posterior pituitary? (A) Thyroxine and insulin. (B) Vasopressin and oxytocin. (C) Cortisol and adrenaline. (D) Growth hormone and prolactin. (E) Follicle-stimulating hormone and Luteinizing hormone.

20. The Nobel Prize in Physiology or Medicine 2014 was awarded for the discovery of place and grid cells, which are responsible for: (A) Circadian rhythm. (B) Special navigation. (C) CAT T cell therapy. (D) Spinal cord development (E) Cardiac regeneration

22. Which of the following statements about the effects of oxaliplatin on SW480 colon cancer cells, as observed in the DNA content histogram plots, is incorrect?  (A) An increase in the sub-G1 population after oxaliplatin treatment indicates a rise in apoptotic cells due to DNA fragmentation. (B) Oxaliplatin treatment leads to DNA damage in SW480 colon cancer cells. (C) The accumulation of cells in the G2/M phase after oxaliplatin treatment suggests cell cycle arrest at this phase. (D) Oxaliplatin treatment causes a majority of SW480 cells to pass through the G1 phase, indicating enhanced cell proliferation. (E) Cells with a 4N DNA content cannot be distinctly separated into G2 and M phases due to their similar DNA content.

23. Atrial enlargement involves the expansion of the heart's atrial chambers, often due to conditions like hypertension or heart valve issues. Which of the following statements about the surface electrocardiogram (ECG) findings in Lead II for atrial enlargement is incorrect?  (A) The ECG criteria for left atrial enlargement (LAE) displays Lead II (B)The ECG criteria for right atrial enlargement (RAE) displays Lead II (C) In cases of atrial enlargement, the QRS complex in Lead II is significantly widened. (D) The presence of atrial enlargement can lead to a deviation in the axis of the P- wave in Lead II. (E) The sinus node rhythm remains normal.

24. Which of the following statements about the ABO, Rh, and Bombay (hh) blood group systems is incorrect? (A) Individuals with the Bombay blood type do not express the H antigen, which is a precursor for A and B antigens, making them unable to form A or B antigens regardless of their genotype. (B) A person with the Bombay blood type will test as type O in standard ABO testing. (C) An individual with the Bombay blood type can safely receive blood from an ABO type O, Rh-negative donor without any risk of a hemolytic reaction. (D) In the Rh system, Rh-negative individuals do not have the D antigen on their red blood cells and can develop antibodies against Rh-positive blood. (E) People with AB blood type are universal recipients in the ABO system, but their Rh factor still determines compatibility with Rh-positive or Rh-negative blood.

25. Which of the following statements about parthenogenesis is correct? (A) Parthenogenesis, a form of asexual reproduction, always results in the production of genetically identical offspring, similar to cloning. (B) In arrhenotokous parthenogenesis, females are produced from unfertilized eggs, while males are produced from fertilized eggs. (C) In parthenogenesis, offspring produced are always genetically diverse due to the random combination of chromosomes during egg formation. (D) Artificially induced parthenogenesis through electric stimulation can lead to the development of embryos from unfertilized eggs in mammals. (E) Parthenogenesis is a common reproductive strategy in most mammalian species, including primates.

26. Which of the following statements about the etiology and treatment of Rheumatoid Arthritis (RA) is incorrect? (A) The efficacy of biologic DMARDs (Disease-Modifying Antirheumatic Drugs) in RA treatment is primarily due to their ability to replace damaged joint tissues through regenerative mechanisms. (B) Epigenetic modifications, such as DNA methylation and histone modifications, play a significant role in the pathogenesis of Rheumatoid Arthritis by influencing gene expression related to immune response. (C) The presence of specific autoantibodies, such as rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs), is a key diagnostic marker and plays a role in the pathogenesis of RA. (D) Environmental factors such as smoking and obesity are known to increase the risk of developing RA and can exacerbate the severity of the disease. (E) Gut microbiota dysbiosis has been implicated in the pathogenesis of RA, with certain bacterial species potentially triggering or exacerbating the autoimmune response.

27. Which of the following organelles does not correctly match its membrane structure? (A) Mitochondria - Double membrane. (B) Centrosome - No membrane-bound. (C) Nucleus - Double membrane. (D) Autophagosome - Single membrane. (E) Phagophore - Single-membrane.