The tapetum lucidum helps nocturnal animals see in the dark; it exists as a thin layer of tissue behind the retinas of nocturnal animals, reflecting light and producing shine. The eyes of many animals contain photoreceptors, which function as light-receiving organelles. These components work in conjunction with the brain and brighten images, helping animals see during the day.
The tapetum lucidum has the opposite effect of photoreceptors. These equally important organelles reduce brightness, providing night vision in nocturnal animals. Typically light hits photoreceptors from direct sources, but tapeta bounce light back towards the source, ultimately preventing absorption. This structure appears in some primates, raccoons, opossums, dogs, cats, foxes, horses and even some fish. The tapetum lucidum appears in photographs as a bright light within the animals' eyes. Like the animals in which they reside, the tapetum lucidum organelles come in various shapes, sizes and colors. They appear as white structures in some eyes, and as yellow or blue objects in others. The color of tapeta depends largely on the chemical and physical composition of eyes, including the amount of pigment in them and presence of certain substances such as zinc and riboflavin. Scientists classify tapeta lucida into four distinct groups; organelles in these groups vary in size, shape and composition.Learn More
The life cycle of the rabies virus is transmission, incubation, early symptoms (prodrome period) and encephalitis phase. Rabies is transmitted to a human or other animal through saliva from an infected animal, in which case transmission occurs from a bite or scratch. The final phases of rabies result in death.Full Answer >
Make an edible animal cell model using Jell-O and a variety of different candies such as M&M'S, gumdrops and gummy worms. A large Ziploc bag is required to set the Jell-O and is used to represent the cell's membrane.Full Answer >
The enthalpy of vaporization is the energy, in the form of heat, that a substance needs to change from a liquid to a gas at a constant temperature and pressure. Enthalpy of vaporization, designated as "delta H vap," is measured in kilojoules per mole of substance. The amount of heat needed to change 2.2 pounds of water into steam is 2,257 kilojoules, or 2,2257 kJ/mol.Full Answer >
French scientist Anselme Payen discovered the enzyme diastase in 1833. Payen, a chemist, later isolated diastase into its concentrated form. Diastase breaks down maltose, a starch, into dextrose, and the enzyme is commonly found in malt, barley and the human pancreas.Full Answer >