Answer:
In human vision, the cone visual opsins are grouped into four photoreceptor protein families LWS, SWS1, SWS2, RH2
.
- SWS1: produce pigments sensitive to very short wavelengths, UV-violet, 360-450 nm.
- SWS2: produce pigments sensitive to short wavelengths, blue, 450-495 nm
- RH2: produce pigments sensitive to medium wavelengths, green, 495-560 nm
- LWS: produce pigments sensitive to long wavelengths, yellow-red, 560-770nm.
Explanation:
Photoreceptor proteins are light-sensitive proteins that mediate light-induced signal transduction, thus they are involved in the sensing and response to light in a variety of organisms.
The photoreceptor proteins are classified based on the chemical structure of the chromophores involved, the light absorption and on the protein sequence.
This photoreceptor proteins are located at the cone photoreceptor cells and are responsible of photopic vision.
For scotopic vision, rhodopsin is responsible. Rhodopsins are the visual pigments (visual purple) of the rod photoreceptor cell in the retina. They are responsible of human vision in dim light, as it contains a sensory protein that converts light into an electric signal.
Answer:
B) the slow rate at which diffusion occurs over large distances.
Explanation:
The complexity of the respiratory system is direct proportional with the size of the organism. As an organism size increases, diffusion begins to take place over a larger distance and the ratio of surface area to volume is seen to decrease. In unicellular organisms, diffusion across the cell membrane is adequate for distributing oxygen to the cell unlike in multicellular organisms.
Diffusion is known to be a slow, gradual and passive transport activity. It is important that for diffusion to be a pratical way of supplying oxygen to the cell, the amount of oxygen intake must be the same as the amount of diffusion across the membrane. This implies that, if the cell happens to be very large or thick, diffusion would not serve as the best means to distribute oxygen swiftly and in the right quantitiy to the inner region of the cell.
We can say that reliance on diffusion as a tool of supplying or distributing oxygen and extracting carbon dioxide is actually attainable only for small size organisms or the ones that possess a highly-flattened bodies, e.g. flatworms (Platyhelminthes).
Thus, this accounts for why Larger organisms had to develop specialized respiratory tissues, such as gills, lungs, and respiratory passages in conjunction with a complex circulatory systems, to disburse oxygen all through their entire body and to compensate for the slow rate at which diffusion occurs over large distances.
All words with a repeated letter are allowed. Green glass door, apple and ball.
Hormones that bind to plasma proteins are insoluble in water meaning that they cannot be transported freely through the blood. Usually those hormones are lipid derivate (cholesterol derivate) such as steroid hormones (estradiol, testosterone). Transport proteins are proteins that hold hormones inactive in systemic circulation and release them when necessary. So, transport proteins are reservoir of hormones within the circulatory system.
