Molecules: Interactions Within Organisms


Related Posts:


Source: Image by MasterTux from Pixabay

Molecules: Interactions Within Organisms (Campbell Biology)

At lower levels of organization, the interactions between components that make up living organisms—organs, tissues, cells, and molecules—are crucial to their smooth operation. Consider the regulation of blood sugar levels, for instance. Cells in the body must match the supply of fuel (sugar) to demand, regulating the opposing processes of sugar breakdown and storage. The key is the ability of many biological processes to self-regulate by a mechanism called feedback.

In feedback regulation, the output or product of a process regulates that very process. The most common form of regulation in living systems is negative feedback, a loop in which the response reduces the initial stimulus. After a meal the level of the sugar glucose in your blood rises, which stimulates cells of the pancreas to secrete insulin. Insulin, in turn, causes body cells to take up glucose and liver cells to store it, thus decreasing blood glucose levels. This eliminates the stimulus for insulin secretion, shutting off the pathway. Thus, the output of the process negatively regulates that process.

Though less common than processes regulated by negative feedback, there are also many biological processes regulated by positive feedback, in which an end product speeds up its own production. The clotting of your blood in response to injury is an example. When a blood vessel is damaged, structures in the blood called platelets begin to aggregate at the site. Positive feedback occurs as chemicals released by the platelets attract more platelets. The platelet pileup then initiates a complex process that seals the wound with a clot.

Source:

Urry, Lisa A.. Campbell Biology. Pearson Education. Kindle Edition. https://www.pearson.com/us/higher-education/series/Campbell-Biology-Series/2244849.html

Related Research

Research Article: Comprehensive Map of Molecules Implicated in Obesity

Date Published: February 17, 2016 Publisher: Public Library of Science Author(s): Jaisri Jagannadham, Hitesh Kumar Jaiswal, Stuti Agrawal, Kamal Rawal, Filippo Castiglione. http://doi.org/10.1371/journal.pone.0146759 Abstract: Obesity is a global epidemic affecting over 1.5 billion people and is one of the risk factors for several diseases such as type 2 diabetes mellitus and hypertension. We have constructed … Continue reading

Research Article: Chapter 3: Small Molecules and Disease

Date Published: December 27, 2012 Publisher: Public Library of Science Author(s): David S. Wishart, Fran Lewitter, Maricel Kann Abstract: “Big” molecules such as proteins and genes still continue to capture the imagination of most biologists, biochemists and bioinformaticians. “Small” molecules, on the other hand, are the molecules that most biologists, biochemists and bioinformaticians prefer to … Continue reading

Research Article: Functional Identification of Neuroprotective Molecules

Date Published: November 24, 2010 Publisher: Public Library of Science Author(s): Cheng Dai, Dong Liang, Huiwu Li, Masayuki Sasaki, Ted M. Dawson, Valina L. Dawson, Maria A. Deli. http://doi.org/10.1371/journal.pone.0015008 Abstract: The central nervous system has the capacity to activate profound neuroprotection following sub-lethal stress in a process termed preconditioning. To gain insight into this potent survival … Continue reading

Research Article: A Single Molecule Scaffold for the Maize Genome

Date Published: November 20, 2009 Publisher: Public Library of Science Author(s): Shiguo Zhou, Fusheng Wei, John Nguyen, Mike Bechner, Konstantinos Potamousis, Steve Goldstein, Louise Pape, Michael R. Mehan, Chris Churas, Shiran Pasternak, Dan K. Forrest, Roger Wise, Doreen Ware, Rod A. Wing, Michael S. Waterman, Miron Livny, David C. Schwartz, Joseph R. Ecker Abstract: About … Continue reading