which one is more harmful?

[forchina]

Vineger interupts the tertiary (and so quarternary) structure of proteins by reactions between the H+ and OH- in acidic and basic solutions with amino acids' R variable groups. Thus they leave holes in the cell membrane where proteins have been comprimised and so the membrane is unable to control what goes in an out of the cell anymore.
While detergents break up or emulsify the phospholipids in the membrane and also can't control.

Is there any answer to which one is more harmful or are they equally harmful? Does one damage the membrane quicker?

[Bad Student]

I'm not sure about this but by your description, detergents sound more harmful because  phospholipids constitute a greater proportion of the cell's surface area, so destroying them would compromise the plasma membrane by a greater amount.

[forchina]

yeah man that kinda makes more sense 

[alondouek]

The phospholipid membrane is composed mainly of, well, phospholipids. Technically, exposure of membrane proteins to vinegar could denature these proteins somewhat, but it's not really too much of a problem as cell membranes would rarely ever come directly into contact with vinegar. If by vinegar you mean pure acetic acid (pH 3 if I recall), then you might be in trouble; but if you're talking about commercial cooking vinegar, the acid is so dilute, it's not really a problem.

I think you're getting a bit confused with detergents. Detergents are composed of small, spherical phospholipid-composed aggregates called micelles. When you put detergent on a greasy pan, for example, the micelles absorb and lock the grease inside them. With your knowledge of how different parts of the phospholipid molecule are hydrophilic and hydrophobic, you should be able to see how this could occur using the image below:

These micelles wouldn't have that much of an effect on a membrane, because of the membrane's fluid-mosaic model. Micelles can absorbs and contain small 'globs' of lipid-based substances (i.e. grease), but they wouldn't be able to efficiently break apart a cell membrane due to the presence of cholesterol and other stabilising substances.