During a clinical investigation, a patient's blood profile reveals a fasting plasma glucose concentration of 8.5 mmol dm-3 (normal range: 3.9−5.5 mmol dm−33.9 - 5.5\text{ mmol dm}^{-3}3.9−5.5 mmol dm−3) alongside elevated plasma insulin concentrations.
Which of the following explains these clinical observations?
The patient has Type 1 diabetes, caused by autoimmune-mediated destruction of pancreatic β\betaβ-cells, which prevents the translocation of GLUT4 transporter proteins to the cell-surface membrane of target cells.
The patient has Type 2 diabetes, where target cells show insulin resistance, disrupting the signaling pathway required to translocate GLUT4 transporter-containing vesicles to the cell-surface membrane.
The patient has Type 2 diabetes, caused by glucagon failing to bind to receptors on pancreatic α\alphaα-cells, which prevents the activation of adenylate cyclase and leads to uncontrolled glycogenesis.
The patient has Type 1 diabetes, where pancreatic α\alphaα-cells secrete insulin in response to elevated glucagon levels, activating the second messenger model and increasing glycogenolysis.
22 exam-style questions on OCR GCSE Biology 3.3 Maintaining internal environments, covering 3.3.1 Importance of a constant internal environment, 3.3.2 The skin and body temperature, 3.3.3 Insulin and blood sugar, 3.3.4 Glucagon and blood sugar, 3.3.5 Type 1 and type 2 diabetes, 3.3.6 Osmotic changes in body fluids, 3.3.7 Kidneys and water balance, 3.3.8 Structure of the kidney and tubule, 3.3.9 ADH and kidney tubule permeability, and 3.3.10 Responses to temperature and osmotic challenges. Each one has a worked solution and a mark scheme showing where the marks go.