Related Experiment Video
Updated: Jun 19, 2026
03:54
Observation of Photobehavior in Chlamydomonas reinhardtii
Published on: May 6, 2022
THE PHOTOTROPIC EFFECT OF POLARIZED LIGHT.
1Laboratory of General Physiology, Harvard University, Cambridge.
The Journal of General Physiology
|October 30, 2009
Summary
Light
Area of Science:
- Plant Biology
- Photobiology
- Cellular Physiology
Background:
- Phycomyces exhibits phototropism, a growth response to light.
- The interaction between polarized light and cellular structures is not fully understood.
Purpose of the Study:
- To investigate the phototropic response of Phycomyces to plane-polarized light.
- To determine if specific cellular mechanisms are affected by light polarization.
Main Methods:
- Exposing growing Phycomyces cells to polarized light.
- Measuring the phototropic effect in relation to the cell's axis.
- Analyzing reflection losses at the cell surface.
Main Results:
- A difference in phototropic effect was observed based on the light's polarization plane relative to the cell axis.
- This difference is mainly attributed to variations in light reflection at the cell surface.
- The observed effects align with existing phototropism theories for this organism.
Conclusions:
- No unique effect of polarized light on Phycomyces growth processes is required.
- Reflection losses significantly influence the phototropic response to polarized light.
- The study clarifies the physical basis of polarized light's effect on Phycomyces phototropism.
Related Concept Videos
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
02:26Photoelectric Effect
When light of a particular wavelength strikes a metal surface, electrons are emitted. This is called the photoelectric effect. The minimum frequency of light that can cause such emission of electrons is called the threshold frequency, which is specific to the metal. Light with a frequency lower than the threshold frequency, even if it is of high intensity, cannot initiate the emission of electrons. However, when the frequency is higher than the threshold value, the number of electrons ejected...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
02:00Photoreceptors and Plant Responses to Light
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
03:09Measuring Reaction Rates
Polarimetry finds application in chemical kinetics to measure the concentration and reaction kinetics of optically active substances during a chemical reaction. Optically active substances have the capability of rotating the plane of polarization of linearly polarized light passing through them—a feature called optical rotation. Optical activity is attributed to the molecular structure of substances. Normal monochromatic light is unpolarized and possesses oscillations of the electrical field in...
02:24Properties of Enantiomers and Optical Activity
It is essential to understand the difference between chiral and achiral interactions and the implications thereof in optical activity and their applications. Just as our feet, which are chiral, interact uniquely with chiral objects, such as a pair of shoes, but identically with achiral socks, enantiomers of a molecule exhibit different properties only when they interact with other chiral media. An example of a significant implication from this facet is the phenomenon known as optical activity,...