Phospholipid

Where can I find a picture of a double phospholipid bilayer?

New postby Hulda » 29 Oct 2012, 08:26

All I can find are pictures of phospholipid bilayers. I need a double phospholipid bilayer. Where can I find one?
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New postby Vaughn » 29 Oct 2012, 08:26

If you mean like in the case of the double membrane of gram-negative bacteria:
http://microbewiki.kenyon.edu/index.php/Proteobacteria

Otherwise can you be more specific what and why you need it?
Are you looking for double membranes of mitochondria/chloroplasts?
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What feature of a phospholipid makes them suitable for...

New postby Elenore » 29 Oct 2012, 08:26

What feature of a phospholipid makes them suitable for plasma membranes?

A) The uncharged,nonpolar,hydrophobic tails interact creating a membrane that is not permeable to most dissolved solutes.

B) The hydrophobic lipid portion allows water soluble molecules o freely diffuse through a phospholipid membrane
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New postby Tianna » 29 Oct 2012, 08:26

A. The plasma membrane has to act as a barrier for the cell. While some solutes freely passage the membrane, many must be actively transported across the membrane. This is how the cell controls its internal environment.
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What is the siginificance of the phospholipid bilayer in...

New postby Debby » 29 Oct 2012, 08:26

What is the siginificance of the phospholipid bilayer in the plasma membrane?

Ok, i understand how they are set up - hydrophilic heads, hydrophobic tails and proteins sandwhiched in between. But, WHY are they set up like this? Why is important for the tails to be facing one way, and heads to be facing another? Please Help ASAP!
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New postby Cassi » 29 Oct 2012, 08:26

The structure of a bilayer explains its function as a barrier. Lipids are amphiphilic molecules since they consist of polar head groups and nonpolar acyl tails. The bilayer is composed of two opposing layers of lipid molecules arranged so that their hydrocarbon tails face one another to form an oily core, while their charged heads face the aqueous solutions on either side of the membrane. Thus, the bilayer consists of the hydrophobic core region formed by the acyl chains of the lipids, and membrane interfacial regions that are formed by the polar head groups of lipids. The hydrophilic interfacial regions are saturated with water, whereas the hydrophobic core region contains almost no water.

Because of the oily core, a pure lipid bilayer is permeable to small hydrophobic solutes, but has only a very low permeability to polar inorganic compounds and ionic molecules.
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Would it be possible for polar molecules or ions to move...

New postby Santos » 29 Oct 2012, 08:26

Would it be possible for polar molecules or ions to move through the phospholipid bilayer?

Would it be possible for polar molecules or ions to move through the phospholipid bilayer? Why or why not?
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New postby Evelina » 29 Oct 2012, 08:26

Yes, this happens all the time in living cells, mainly because of transporters or channels that allow polar molecules and ions through the lipid bilayer of the membrane. Without such help, it is not likely that these polar molecules would find their way across the membrane.
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What types of bacteria have a phospholipid bilayer?

New postby Nerissa » 29 Oct 2012, 08:26

I am trying to complete my study guide for my microbiology exam and for the life of me I cannot find this one answer. Any help would be much appreciated. Thanks
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New postby Emelda » 29 Oct 2012, 08:26

My pathology textbook says: Gram negative bacteria have a thin cell wall sandwiched between 2 phospholipid bilayers. So gram negative bacteria? Where the peptidoglycan wall is surrounded with lipoproteins and lipopolysaccharides.
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Why are phospholipid bilayers spheroid and not flat?

New postby Vina » 29 Oct 2012, 08:26

I mean, from what I know, I understand the why of a bilayer (hydrophillia and phobia) but not that of a membranous spheroid.

How or why, in the very beginning, was a spheroid formed, rather than a flat sheet?
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New postby Anita » 29 Oct 2012, 08:26

If it is flat, it will have an edge. The edge in water will have a hydrophobic region which will "search" for a nonpolar molecules. It will eventually find it by forming a sphere if it is of sufficient size.
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What is meant when the tails of a phospholipid are...

New postby Willis » 29 Oct 2012, 08:26

What is meant when the tails of a phospholipid are considered hydrophobic?

?
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New postby Jeanice » 29 Oct 2012, 08:26

The tails are long chain hydrocarbons which means they have fully bonded carbons only. This makes them hydrophobic because it means they can't (have ne electrons available to) interact with water.

They are pushed to ineteract with each other instead and thus will spontaneously form either a micelle or a bilayer, which in a cell is handy because it forms the cell membrane.
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What are the monomers of nucleic acids and what are the 3...

New postby Betty » 29 Oct 2012, 08:26

What are the monomers of nucleic acids and what are the 3 parts of a phospholipid?

Thanx so much 4 ur help!
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New postby Genia » 29 Oct 2012, 08:26

Nucleotides are the monomers of nucleic acid.
They contain either a purine or a pyrimidine base attached to either a ribose or a deoxyribose. Then they form chains for RNA and DNA
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