METC Institute Blog

GAMSAT Key Concepts in Biological Science

Posted by Mat on Feb 15, 2019 9:13:55 AM

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In your study of physiology and biology, you will no doubt have come across the concept of organisms being based on organs which are in turn based on cells. Not all cells are the same and it turns out that complex life requires a rich diversity of cell types. In order to understand biological systems most students will have studied the cell, its specialist components, and their functions. From here, students typically study the different forms of cells (prokaryotes vs eukaryotes etc.) and the different forms of life (single-cell organisms vs multicellular complex life).

During the study of such a microcosm, it is easy to lose sight of the bigger picture: The major function of life is to survive and to hopefully propagate. The only way for an organism to survive is for cells (or a cell in the case of a unicellular organism) to maintain the conditions of life. As you may be aware, this is referred to as homeostasis. This is perhaps the most important concept to consider in your study of biological systems as it predicts the behaviour of systems entirely. Either directly or indirectly, most systems function to maintain the conditions required for life. Some systems are not geared for homeostasis and in such cases systems have specific functions such as the special senses. In these cases, the special functions exist in order to increase chances of survival or propagation.

In your studies of physiology, it is therefore important to understand three things about all of the major systems you study. If you cannot explain these in a basic sense and you have studied the systems, it is likely you have become too consumed in the details. The three key aspects of each system you need to know are as follows:

  1. What does the system do?
  2. Why does it do this?
  3. How does the system do it?

Taking this critical approach to each biological/physiological system you study is important for many reasons. Firstly, by asking such questions and ignoring everything else (for now), you are taking a critical approach to the system – all you want to know is what the system does, why this is important and how it meets this objective. Secondly, by understanding clearly the purpose and function of each system, you will be able to easily apply this universal knowledge to comparable systems in different organisms/contexts. If you have sat GAMSAT before, you will know how important it is to be able to apply existing knowledge in new contexts.

For example, consider the respiratory system:

  1. The system provides important substrate to the body (oxygen). The system also removes waste (carbon dioxide and by extension protons) from the body. The system also has minor roles in temperature regulation and some endocrine function.
  2. The system operates to ensure ATP can be produced (via oxidation), and damaging waste products do not accumulate. In other words, the system controls blood O2 and CO2 concentration, and is one way of controlling pH.
  3. The system manages O2 and CO2 concentrations via dynamic pressure changes in turn based upon changes in volume. Volume change is controlled by contraction and relaxation of muscles surrounding the thoracic cage. Inside the bellows (lungs), exchange occurs down concentration gradients (passive diffusion) between the lungs and blood stream. Without a moving stream of blood, the system is redundant.

Once you understand the basics, it is time to increase the level of detail. In this case, you may choose to learn more about gas transport, or choose to learn the names of the muscles responsible for inspiration and expiration. Most important however is that you have no doubt in your mind as to the key questions.

In next week’s webinar, we will revisit the concept of homeostasis and consider the three important questions for each of the major physiological symptoms.

 

Read our last blog HERE.

Topics: gamsat, gamsatpreparation, gamsatsection3