Cells and Chemical Reactions: Reaction Rates in Cells

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Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the last of four Science Objects in the Cells and Chemical Reactions SciPack. It investigates how the reaction rates in cells can be affected by temperature, pH, hydration levels, and enzymes.

Chemical reaction rates are affected by the conditions in which they occur (or cannot occur). Most cells must function within a narrow range of temperature and acidity because they are part of a living system. At very low temperatures, reaction rates are too slow. High temperatures and/or extremes of acidity can irreversibly change the structure of most protein molecules. Even small changes in acidity can alter the molecules and how they interact. Hydration levels also affect chemical reactions in cells; dehydrated cells lack the solvent and substrate or substrate structure needed for chemical reactions to proceed. Both decomposition and synthesis of molecules (involving energy transfer) are made possible in cells by a large set of protein catalysts, called enzymes. Without enzymes to catalyze the chemical reactions necessary for life, the conditions (including temperature) inside of cells would slow chemical reaction rates below what is necessary to stay alive. Like other protein reactions, the effectiveness of enzymes reactions is affected by temperature and acidity.

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Reviews (5)
  • on Wed Oct 21, 2015 10:01 PM

I love how I re-learned most of my cell knowledge from this. It was very informative and helped me refresh my memory about cells.

Dina Oti
Dina Oti

  • on Tue Sep 02, 2014 5:18 AM

I really enjoy Science Objects. In 1-3 hours, the Cells and Chemical Reactions: Reaction Rates in Cells Science Object will help me re-learn, refresh, or learn for the first time some critical science concepts I will have to know to obtain my Science Educator credentials. I appreciate that I can complete them at my own pace, and that, if used as park of a SciPack, I have access to a content expert to go to for help. The NSTA Learning Center Science Objects are really beneficial!

Naomi Beverly  (Marietta, GA)
Naomi Beverly (Marietta, GA)

  • on Tue Aug 20, 2013 10:46 PM

I used this as a prep for the PA Keystone Tests with great success. It filled in a lot of gaps and increased student scores. We did the textbook exercises and then once a week did the science objects. This was a great chemistry review as well! 100% Great job!

James Johnson  (Custer City, PA)
James Johnson (Custer City, PA)

  • on Sun Oct 30, 2011 6:56 PM

The knowledge of how the cells in our bodies and the bodies of other non-synthetis organisms pull together so many different components to complete so many different functions in such short periods of time is truly amazing. The more complex the subject matter seems to be the more these SciObjects make it plain and simple. I was truly awed by how negotiable the content of this SciObject was and how attainable the concepts seemed to be. I take my hat off to the developers of these resources; your work is stupendous!

Duane Little  (Washington, DC)
Duane Little (Washington, DC)

  • on Sat Jan 12, 2013 10:07 PM

I like the presentation but the pop up on rates tends to take a long time to develop and I'm afraid my students would lose interest in the process and become disengaged before the demonstrated was concluded. Possible the actual rate of the demonstration could be increased to show an effect in 4 seconds but it would only take 2 seconds to show it. It's an attention span thing.

James Johnson  (Custer City, PA)
James Johnson (Custer City, PA)

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