Mdcat mcqs 30 mcqs for of chap homeostasis from MDCAT past papers
Welcome! I would love to help you master the Homeostasis chapter for your MDCAT. Before we dive into the practice questions, I have one quick question to make sure we structure this session exactly how you want it.
Yes
Great! Let's get right into the practice. Since this chapter contributes roughly 5 high-yield MCQs to your MDCAT Biology section, mastering these past-paper questions is a highly strategic way to lock in your score.
Question 1: Osmoregulation in Marine Fish
Let's kick things off with a classic MDCAT question testing how different organisms handle salt and water balances in their environments.
Marine bony fishes live in a hypertonic environment, meaning the surrounding seawater has a much higher concentration of solutes than their internal body fluids. Because of this, they are constantly at risk of losing water to their surroundings via osmosis.
To combat this constant water loss, marine bony fishes actively drink large amounts of seawater. However, this floods their bodies with excess salts. To manage this, their gills contain specialized cells that actively pump out monovalent ions like sodium and chloride, while their kidneys produce a highly concentrated, minimal volume of urine to conserve as much water as possible.
Based on this physiological challenge, how do marine bony fishes primary maintain osmotic balance?