Recent questions tagged biomolecules

Description : What is the nature of the interactions between biomolecules?

Last Answer : Interactions between biomolecules depend on the forming and breaking of chemical bonds. The covalent bond is the strongest chemical bond. It links individual atoms within a molecule and ... specificity, and response to water. Although noncovalent interactions are weaker than covalent bonds .

Description : What is inside a living cell?

Last Answer : The inside of a cell is crowded with molecules, and these are in continuous vigorous motion that is driven by thermal energy. In prokaryotic cells the cytoplasm is the only compartment; in ... ones. It is the diffusion and collisions between molecules that enable biochemical reactions to occur. 

Description : Why is water such an important molecule in living systems?

Last Answer : The strength and specificity of interactions between biological molecules depend on the medium in which they reside. The major biological solvent is water, although fat deposits readily dissolve ... gas at normal atmospheric temperatures and pressures, like dinitrogen of molecular weight 28. 

Description : Is it strictly correct to call proline an amino acid? 

Last Answer : No. The side chain of proline bends around and is covalently linked to the backbone nitrogen atom replacing one of the hydrogen atoms. Thus it is actually an imino acid. 

Description : What is the difference between a sugar and a carbohydrate? 

Last Answer : Sugar is a term that is sometimes used incorrectly to refer to carbohydrates in general, because many carbohydrates have a sweet taste. But not all carbohydrates are sugars, e.g., starch. ... specifically to sucrose, or perhaps to a few other simple carbohydrates such as fructose and glucose. 

Description : β-D-Glucose is the most prevalent monosaccharide in the bloodstream. It can react with many differentcompounds. What is the chemical basis of this reactivity?

Last Answer : Glucose is an aldehyde and hence is a reducing compound. The aldehyde group is reactive and can be reduced to form an alcohol, can be oxidized to form a carboxylic acid, or can react with many other compounds to form a glucosyl adduct with them.  

Description : Can cholesterol form micelles and bilayers?

Last Answer : Cholesterol does not form micelles because it is not sufficiently amphiphilic (even though it does have an OH group) and its flat, rigid, fused-ring structure gives a solid rather than a liquid ... it constitutes ∼25% of the mass of the lipid bilayer in the plasma membranes of mammalian cells. 

Description : What are the structural and chemical reasons why bile salts don’t form typical micelles?

Last Answer : Although bile salts possess a polar head group, the hydrocarbon tail usually contains polar hydroxyl groups. Therefore the rigid ring system gives a tightly packed, almost solid, nonpolar phase rather ... liquid one. However, like cholesterol, bile salts can form mixed micelles with phospholipids.