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Video
Berg begins his lecture with a brief history of observations of bacterial motion. He then uses physics to describe the many hurdles that E. coli must overcome as it tries to swim up or down a chemical gradient. For instance, an entity as tiny as E. coli is constantly buffeted by Brownian motion and can neither stay still nor swim in a straight line. Then there is the question of how E. coli senses a gradient and translates that information into a change in its direction of movement. And finally, how does E. coli use its flagella to generate thrust at all? In Part 2, Berg explains that E. coli travels using a series of runs, when it moves in a straight line, and tumbles, when it changes direction. During a run, all of the flagella are moving counterclockwise in a tight bundle. During a tumble, one or more flagella switch to a clockwise movement and disengage from the bundle causing a change in the swimming direction. The motor that drives the rotation of the flagella is an amazing structure made of about 20 different protein parts. Berg tells us that chemosensory receptors on the cell surface detect a chemical gradient and transfer this information, via protein phosphorylation, to the motor. This chemical modification determines the direction of motor rotation and, hence, the direction the E. coli swims. An amazing system that E. coli has been perfecting for millions of years!
- Subjects:
- Physics and Biology
- Keywords:
- Bacteria -- Motility Physics Escherichia coli
- Resource Type:
- Video
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Others
In this animated learning object, students examine the life cycles of a virus.
- Subjects:
- Health Sciences, Medical Laboratory Science, and Biology
- Keywords:
- Viruses
- Resource Type:
- Others
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Video
In this screencast, learners examine the bones of the appendicular skeleton.
- Subjects:
- Health Sciences, Rehabilitation Science, and Biology
- Keywords:
- Human skeleton Human anatomy
- Resource Type:
- Video
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Video
Explore what proteins are, their structure, and their functions.
- Subjects:
- Medical Laboratory Science and Biology
- Keywords:
- Proteins -- Structure
- Resource Type:
- Video
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Others
In an interactive exercise, learners identify the human body sites that harbor a normal resident flora and the sites that are sterile.
- Subjects:
- Health Sciences and Biology
- Keywords:
- Human body Bacteria
- Resource Type:
- Others
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Others
This learning object demonstrates the process by which antigens are identified, processed, and presented to mediators of the cellular immune system.
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Others
In this animated learning object, learners examine the regulation of inducible operons in bacterial systems.
- Subjects:
- Medical Laboratory Science and Biology
- Keywords:
- Operons
- Resource Type:
- Others
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Others
In this animated object, learners examine the various connective tissue layers of the muscle organ. The terms "prime mover," "synergist," "antagonist," "origin," and "insertion" are defined.
- Subjects:
- Rehabilitation Science, Health Science, and Biology
- Keywords:
- Muscles -- Anatomy
- Resource Type:
- Others
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Video
In this learning activity you'll assemble the components of a prokaryotic cell and match the names and functions with each structure.
- Subjects:
- Biology
- Keywords:
- Prokaryote
- Resource Type:
- Video
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Others
Learners study two diagrams of the lymphatic system and then test their knowledge in drag-and-drop exercises.
- Subjects:
- Health Sciences and Biology
- Keywords:
- Lymphatics
- Resource Type:
- Others