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What type of macromolecule is cholesterol?

Lipids have a hydrocarbon side chain. Based on the nature of this chain, the lipid may be further classified as saturated or unsaturated. Saturated lipids have no double bonds in the molecule, while unsaturated lipids have double bonds. The terms "saturated," "mono-unsaturated" and "poly-unsaturated" refer to the number of hydrogens attached to the molecule. Lipids from plant sources are unsaturated. Lipids in biological membranes are found as double layers and are amphipathic in nature.

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What is gallium?

Dmitri Mendeleev predicted the existence of gallium in 1871 and suggested that its properties would be similar to aluminium. However, it wasn’t until 1875 that gallium was discovered by Paul-Emile Lecoq de Boisbaudran who used electrolysis to separate it out from a solution.\nElemental gallium does not freely occur in nature, but instead occurs as gallium salts in trace amounts of bauxite and zinc ores. Gallium is often produced as a byproduct during the extraction of aluminum from bauxite. Purification of bauxite by the Bayer process results in a high concentration of gallium. Using electro..

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What are the eight minor plates?

The Arabian plate is the second largest of the minor plates, and it is the only other one besides the Indian plate that contains any significant amount of land. The other minor plates are primarily located over oceans or seas, such as the Juan de Fuca plate, which is the smallest of all the plates, and is located off the northwest coast of North America.\nThe seven major tectonic plates contain the majority of land on the planet, with each plate basically having an entire continent located on it. The only exception is the Pacific plate, which mainly contains the Pacific Ocean and its small isl..

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What formula represents an ionic compound?

In formulas for ionic compounds, standard notation lists the cation before the anion. The cation is the ion with a positive charge, while the anion is the ion with a negative charge. In the formula CaCl2, Ca^+2 is the cation and Cl^-1 is the anion. The number of atoms of each element is determined by balancing out the charges.

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What is the largest cell in the world?

Ostrich eggs must be large because they have to have sufficient room to accommodate the large chick that must develop inside. Ostriches are the largest living birds, and as they sometimes reach over 300 pounds in weight, the eggs must be able to withstand the mother’s weight while she performs her incubation duties. By comparison, a human ova is barely visible to the naked eye and has a diameter of about one-tenth of a millimeter.

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Why can't we live on Mars?

The Martian atmosphere is 95-percent carbon dioxide. It is only 0.13-percent oxygen, far less than the 21 percent available on Earth. The atmosphere is also nearly 100 times thinner than Earth's, meaning Mars cannot retain the radiant heat of the sun, so while late afternoon at the Martian equator may be a comfortable 70 F, at night the temperature would fall to 100 F below zero.\nSince humans have lived in space for extended periods of time in ships or orbital station, it's reasonable to suppose that life on Mars is also possible. This assumes that Earth-like atmosphere and temperat..

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What are physical and chemical changes?

Chemical changes occur on the molecular level. The change produces a new substance. Chemical changes include combustion, synthesis, oxidation, neutralization and decomposition. For example, iron rusting is an instance of a chemical change. Food metabolism, burning wood, mixing and acid with a base, baking a cake and using a chemical battery are also examples of chemical changes.\nA chemical change can be determined by evaluating if a reaction has occurred. A chemical reaction may have occurred if a change in light, heat, color, gas production, odor or sound is produced. If a precipitate develo..

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What is diphosphorus pentoxide?

Phosphorous pentoxide's dehydrating properties are powerful enough to cause severe chemical burns upon contact with the skin, eyes, digestive tract or lungs. It generates heat when reacting with water; this heat is sufficient to ignite flammable materials. Phosphoric pentoxide itself is not flammable.\nAs of 2014, it is not legally classified as a hazardous material by the federal government, but state regulations in Massachusetts, New Jersey and Pennsylvania place it on "right to know" lists. Workers in these states have a right to know when they are working with phosphorous pentoxide, t..

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What helps hold the nucleus together?

The lipid bilayer is formed of an inner and outer layer separated by 10 to 50 nanometers. The space between the two layers is called the perinuclear space. Additionally, the envelope gives the nucleus shape and helps control the flow of molecules in and out of the pores of the nucleus. The size of the pores allows the passage of small, water-soluble molecules while preventing larger molecules free passage into the nucleus. Typical mammal cells have roughly 3000 to 4000 pores in the envelope.\nThe function of the nucleus is to monitor and control gene expression and the replication of DNA durin..

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Why do plants have thorns?

Honey locust trees are a prime example of plants with thorns, according to The American Phytopathological Society. Thorns are actually a type of branch, and roses do not have true thorns. Instead, roses have prickles, which are a part of the skin of the plant. Cacti, on the other hand, have spines, which are a modified leaf. Overall, all of these types of growths on plants do the same thing; defend the plant against predators.

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