Biomolecules

- Let's bust some of the common misconceptions from this chapter.

Is pyranose a 5-membered or 6-membered ring? Many times we get the structure of pyranose wrong. It so happens that we confuse pyranose with pyrrole which is a five-membered ring.Also, the word pyranose sounds like"pentose"so we end up drawing a five-membered ring.

But instead of what it seems, pyranose has a six membered ring structure with 5 carbons and one oxygen as shown below:

The name pyranose is derived from pyran (structure below). Pyran has two double bonds in its structure. But, pyranose (structure above) does not have any double bonds in it.

Macromolecules can be viewed easily with the naked eye When we hear the wordmacro in "macromolecules", we think of "large molecules". Something that we can see with our naked eyes. But this is not exactly true. The word "macro"is relative here. They are large compared to other small molecules. Even a large macro-molecule like DNA can not be viewed with the naked eye. You need a high resolution microscope to view it.

Fats are Bad!

In the dietary world, the concept of fat is often related to obesity or some cardiovascular diseases.

But instead some fats are essential for many functions in the body.

For example, monounsaturated and polyunsaturated fats found in plants and healthy oil such as canola and olive oil protect our health and reduce cholesterol. Further, we need fats for the fat soluble vitamins to dissolve in our blood and provide nutrients.

In all this, we should not forget that there are some bad fats - saturated and trans fatty acids. They can raise cholesterol levels and increase the risk of heart diseases.