A 50-year-old woman with a history of chronic arsenic (As) exposure presents with hyperpigmentation, skin lesions, and an increased risk of skin cancer. Which of the following mechanisms best explains the carcinogenic potential of arsenic (As) in this patient?

A 30-year-old factory worker presents with abdominal pain, constipation, and peripheral neuropathy. Blood tests reveal elevated lead (Pb) levels. The patient’s symptoms are attributed to lead-induced inhibition of heme synthesis.Which enzyme in the heme synthesis pathway is most likely inhibited by lead (Pb)?

A 55-year-old male factory worker presents with neurological symptoms, including tremors, memory loss, and irritability, after years of occupational exposure to mercury-containing compounds. His physician suspects heavy metal poisoning and orders tests to assess enzyme function. Which of the following best describes the primary mechanism by which mercury (Hg) exerts its toxic effects on enzymes?

A 52-year-old factory worker exposed to industrial chemicals presents with fatigue, weight loss, and hematuria (blood in urine). A biopsy confirms bladder cancer. The physician explains that exposure to heavy metals increases reactive oxygen species (ROS) formation, causing DNA damage and tumor development. Which of the following heavy metals is most likely responsible for ROS-mediated carcinogenesis?

A 7-year-old child presents with developmental delay, abdominal pain, and irritability. Blood tests show elevated lead (Pb) levels. The physician explains that lead toxicity disrupts heme synthesis and neurological function. Which of the following enzymes is directly inhibited by lead (Pb) toxicity?

A 45-year-old male presents with progressive fatigue and pallor. Laboratory tests reveal low hemoglobin levels and microcytic hypochromic anemia. His physician suspects an essential transition metal deficiency affecting oxygen transport. Which of the following transition metals is most directly responsible for oxygen transport in the body?

Case Scenario: A 28-year-old athlete is undergoing intense endurance training. His body must regulate multiple metabolic pathways in response to energy demands. His physician explains that certain enzymes integrate multiple phosphorylation signals to coordinate cellular metabolism. Which of the following statements best describes the role of phosphorylation as a decision node?

Case Scenario: A 35-year-old woman presents with a rapidly growing breast mass. Biopsy reveals mutations in ATM kinase, a key player in the DNA damage response. Which of the following best describes the role of ataxia-telangiectasia mutated (ATM) kinase in cell cycle control?

Case Scenario: A 50-year-old man with obesity and hyperlipidemia is prescribed metformin, which activates AMP-activated protein kinase (AMPK). His physician explains that AMPK activation reduces lipid synthesis by phosphorylating key metabolic enzymes. Which of the following enzymes is inhibited by phosphorylation in response to AMPK activation?

Case Scenario: A 70-year-old male with metabolic syndrome is found to have elevated acetyl-CoA levels due to chronic overnutrition. His physician explains that high acetyl-CoA can alter enzyme activity via lysine acetylation, affecting metabolic pathways. Which of the following statements best describes the role of lysine acetylation in metabolic enzyme regulation?