Related Concept Videos

Ethics in Research01:56

Ethics in Research

Today, scientists agree that good research is ethical in nature and is guided by a basic respect for human dignity and safety. However, this has not always been the case. Modern researchers must demonstrate that the research they perform is ethically sound.
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Energy and Power of a Wave00:58

Energy and Power of a Wave

The total energy associated with a wavelength is the sum of the potential energy and the kinetic energy. The average rate of energy transfer associated with a wave is called its power, which is total energy divided by the time it takes to transfer the energy. For a sinusoidal wave, energy and power are proportional to the square of both the amplitude and the angular frequency.
Waves can also be concentrated or spread out, as characterized by the intensity of the wave. Intensity is directly...
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Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
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Source And Potency Of Stem Cells01:27

Source And Potency Of Stem Cells

Stem cells are undifferentiated cells with extensive self-renewal properties that help them maintain their population during the fetal and adult stages of life. They can specialize in all cell types of the human body. However, their differential potential may vary and can be classified into five types. Stem cells can be (1) Totipotent, (2) Pluripotent, (3) Multipotent, (4) Oligopotent, and (5) Unipotent. Each stem cell has a specific origin; the fertilized egg or zygote is a totipotent cell and...
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Hearing01:31

Hearing

When we hear a sound, our nervous system is detecting sound waves—pressure waves of mechanical energy traveling through a medium. The frequency of the wave is perceived as pitch, while the amplitude is perceived as loudness.
52.0K
Radiation: Applications01:17

Radiation: Applications

The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
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