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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, co-developed between FDA and NSTA, second of four Science Objects in the Food Science Safety SciPack. It explores cell functions involving chemical reactions that are made possible by protein catalysts called enzymes. These reactions require a fairly narrow range of temperature and pH. Low temperatures cause them to go too slowly, and high temperatures or acidity can change cell structures. Molecules from the environment may also attach to or pass through a cell's membrane and affect reaction rates. Cells such as bacteria require energy and nutrients from their environment for survival. When they grow to a certain size, bacteria can reproduce by creating a copy of their DNA and then splitting in two. Under optimal conditions, this doubling of bacteria and each of their generated offspring can proceed at a fast rate, expanding a bacterial colony rapidly in a short time. Many of the precautions taken to protect the health of humans focus on limiting the growth of bacterial colonies by creating environmental conditions not favorable for their functioning or reproduction. Variations in genetic information within a population of bacteria can permit some individuals to survive and reproduce more effectively than others in a given environment. Such hardier individuals usually represent only tiny fractions of a population, but their rapid reproduction can quickly give rise to large numbers of successful offspring. This process may give rise to bacterial strains able to survive under new conditions, such as strains with resistance to overused antibacterial drugs, or grant previously harmless bacteria the ability to cause disease.
I really enjoy Science Objects. In 1-3 hours, the Science of Food Safety: Growth and Reproduction of 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 very beneficial! Not only will they enrich my teaching, the knowledge will enrich my life.
Naomi Beverly (Marietta, GA)
question is that it is still not know ,from where the first cell come from,if all cellls arise from preexisting cells.secondly science is said to be advanced,when people have same brain than why they think differently,with negative and positive views and decisions.why some people ar emotional and some are bold and they do wrong things,due to neurons,why something can not be done to release some hormone or enzymes and people do not bring wrong things in brain.
anu nayyar (abudhabi, )
Great review of very general topics, Biology majors will probably be a little bored...
This science object deals with concepts of metabolism of cells/organisms, factors affecting rate of chemical reactions, limitations of cell size, asexual reproduction, population curves, and bacterial variation and adaptations. All of these topics are discussed “under the umbrella” of the potential of illnesses from bacteria and how bacteria survive. All of the information was very good, but this is one of the first objects I’ve completed where it seems that too many different topics were covered without going into enough detail about many of them. There were a couple of quick videos that may be useful in the classroom, but none that stood out. I agree with the other reviewer that this is a good starting point, but I would investigate other resources
This resource does an adequate job of covering the basics of cell growth and respiration, but I would recommend the Cell Structure and Function science objects for their more complete coverage of the topic. The object does contain more content related to the growth of bacteria and other pathogens in food. Basic information; a starting point for most higher-grade teachers.
Jennifer Rahn (Delafield, WI)
$5.95 - Nonmembers