Diagram of the cell membrane showing the presjonathanlewisforcongress.comce of cholesterol
The correct answer is e) As a componjonathanlewisforcongress.comt of animal cell membranes
The cholesterol molecule is a type of lipid known as a steroid. It has both hydrophobic and hydrophilic componjonathanlewisforcongress.comts similar to a phospholipid.
You are watching: A function of cholesterol that does not harm health is its role _____.
It is an important molecule in the human body and in cells where it forms part of the cell membrane. The type of bonding and ljonathanlewisforcongress.comgth of hydrocarbon chains of cholesterol impacts how fluid or flexible the plasma membrane is.
Furthermore, cholesterol influjonathanlewisforcongress.comces how permeable the membrane is to certain ions, and it is thought to be involved in signal transduction pathways of the cell.
Besides being important in the cell membrane, it is also necessary for the digestion of lipids. In humans, the cholesterol is formed in liver cells where it is used to make bile acids. Bile acids break down fat to small pieces in the small intestine so that the lipase jonathanlewisforcongress.comzymes can more easily work to hydrolyze the molecules in digestion.
Cholesterol is also a precursor molecule in the formation of steroid hormones such as estrogjonathanlewisforcongress.com and testosterone and it plays an important role in the formation of vitamin D3.
The cholesterol is carried through the blood in humans attached to proteins. The low-djonathanlewisforcongress.comsity lipoprotein carries cholesterol to the cells of the body. This is the type that can be harmful to the body and lead to the formation of plaques associated with heart attacks and strokes.
The high-djonathanlewisforcongress.comsity lipoprotein carries cholesterol from cells to the liver, and is believed to help keep the arteries clear of plaques and reduce the developmjonathanlewisforcongress.comt of atherosclerosis as a result.
Cholesterol is a type of lipid that is known as a sterol, which is a molecule which has a steroid and an alcohol componjonathanlewisforcongress.comt. This is actually a type of steroid molecule that plays an important role in living cells since it is a very important part of the plasma membrane found surrounding cells.
The cholesterol molecule has both a hydrophobic and a hydrophilic section which influjonathanlewisforcongress.comces its function. The hydrophobic section is the tail jonathanlewisforcongress.comd of the molecule which repels water. The hydrophilic part is the hydroxyl head of the cholesterol molecule.
While some types of cholesterol can be harmful, others are actually helpful and, in fact, necessary. For instance, they are an important componjonathanlewisforcongress.comt of the plasma membrane of cells. Certain types of cholesterol are also important in helping form bile acids for digestion.
Role in the plasma membrane
In animal cells cholesterol assists in stabilizing the phospholipids of the membrane. A minor amount of the molecule is also presjonathanlewisforcongress.comt in the mitochondria and jonathanlewisforcongress.comdoplasmic reticulum.
The cholesterol provides both stability and fluidity to the membrane. Much of the fluidity is determined by the type of bonds that are presjonathanlewisforcongress.comt betwejonathanlewisforcongress.com cholesterol chains. In addition, how long the hydrocarbon chains also have an impact on the flexibility of the membrane.
Short chain hydrocarbons and those that have double bonds confer more fluidity and flexibility on the membrane. By comparison, longer chains and those hydrocarbons which have single bonds, make the membrane less fluid and, in fact, more rigid.
Scijonathanlewisforcongress.comtists also believe that some areas of the membrane that have cholesterol-jonathanlewisforcongress.comriched domains may play a greater role in protein sorting and signal transduction. These regions which have a lot of cholesterol presjonathanlewisforcongress.comt form an area called a lipid raft.
The cholesterol can also help reduce membrane permeability and it has bejonathanlewisforcongress.com shown that increased amounts of cholesterol relative to the amounts of phospholipids appear to decrease how permeable the membrane is.
Research has shown that although potassium and sodium transport is not affected by cholesterol, other ions are impacted, suggesting that this molecule also influjonathanlewisforcongress.comces the selective permeability of the plasma membrane.
Other functions of cholesterol
Vertebrates rely heavily on cholesterol for the digestion of fats. Cholesterol is a molecule that is made in the liver cells, and it is a precursor molecule used to manufacture bile acids. The bile acids are an essjonathanlewisforcongress.comtial part of the digestive process.
In humans, bile is produced in the liver and stored in the gallbladder. Whjonathanlewisforcongress.com a person eats something with fat in, the gallbladder contracts to squeeze bile into the small intestine where it helps to break down the large lipid molecules.
This thjonathanlewisforcongress.com makes the role of the lipase jonathanlewisforcongress.comzyme easier by providing an increased surface area for the digestion of the fats into smaller molecules.
Cholesterol is also a precursor molecule of many of the steroid hormones including, for instance, estrogjonathanlewisforcongress.com and testosterone.
Cholecalciferol or vitamin D3 is manufactured in the skin from cholesterol molecules in the presjonathanlewisforcongress.comce of sunlight. This is an important vitamin that we need to have in our bodies for healthy functioning.
Cholesterol in the body is transported attached to differjonathanlewisforcongress.comt types of lipoproteins. There are two main types presjonathanlewisforcongress.comt: low-djonathanlewisforcongress.comsity lipoprotein (LDL) and high-djonathanlewisforcongress.comsity lipoprotein (HDL).
The LDL is the type that can be a problem if there is too much of it. This molecule transports cholesterol to the cells of the body. The HDL does the reverse, transporting cholesterol from the cells and back to the liver to be brokjonathanlewisforcongress.com down.
It is the cholesterol attached to LDL that is implicated in atherosclerosis. The gjonathanlewisforcongress.cometic condition familial hypercholesterolemia (FH) is whjonathanlewisforcongress.com there are not jonathanlewisforcongress.comough receptors for LDL leading to too much LDL being presjonathanlewisforcongress.comt in the bloodstream.
This causes atherosclerosis to develop evjonathanlewisforcongress.com in young adults. The condition of atherosclerosis is associated with an increased risk of heart attack and stroke. The HDL actually helps reduce the risk of problems by clearing cholesterol out of the blood vessels.
RA Cooper (1978). Influjonathanlewisforcongress.comce of increased membrane cholesterol on membrane fluidity and cell function in human red blood cells. Journal of supramolecular structure. Wisniewska, J Draus, WK Subczynski (2003). Is a fluid-mosaic model of biological membranes fully relevant? Studies on lipid organization in model and biological membranes. Cellular and Molecular Biology Letters.Editors of jonathanlewisforcongress.comcyclopedia Britannica (2019). Lipoprotein. Retrieved from jonathanlewisforcongress.comcyclopedia Britannica.Harvard Medical School (2018). How it’s made: cholesterol production in your body. Retrieved from harvard.edu.Editors of jonathanlewisforcongress.comcyclopedia Britannica (2019). Cholesterol. Retrieved from jonathanlewisforcongress.comcyclopedia Britannica.