Homeostasis is maintained primarily through negative feedback loops. Any deviation from a set point (e.g., normal blood water potential or solute concentration) triggers responses that counteract the change. Question 49 likely required students to interpret how the body responds to dehydration or overhydration. For instance, when a person exercises and loses water through sweat, the blood becomes more concentrated (increased plasma osmolarity). This is detected by osmoreceptors in the hypothalamus, which then initiates two responses: the sensation of thirst and the release of ADH from the posterior pituitary gland.
The 2011 CE Biology examination, particularly Section II Question 49, typically assessed candidates’ understanding of a cornerstone of human physiology: . While the question likely presented a diagram of the nephron or a graph showing changes in blood plasma composition, the underlying theme is the kidney’s role in maintaining a stable internal environment. This essay will explore the biological principles relevant to that question, including negative feedback control, selective reabsorption, and the action of antidiuretic hormone (ADH). ce bio 2011 ii q49
While specific wording may vary by translation, the core of the question typically involves a genetic cross between a heterozygous individual and a homozygous recessive individual—a standard scenario. Subject: Human Genetics / Albinism For instance, when a person exercises and loses
Let = normal allele, Xʙ = recessive disease allele (I use superscript B and b for clarity). While the question likely presented a diagram of