Skip to content

Ap Bio Essays Cell Membrane

Cell membranes are made up of a phospholipid bilayer and various proteins. Phospholipds are amphipathic: one region is hydrophobic (the fatty acid tails) and one is hydrophilic (the cycerole/phosphate head). In an aqueous environment, they congregate into a bilayer to protect the hydrophobic tails. Peripheral and integral proteins can be embedded all around and within the bilayer in what is known as the “fluid mosaic model,” and cholesterol molecules can sit within the layer to improve its fluidity. The membrane proteins can function as enzymes, improving adhesion to neighboring cells, transporting molecules into and out of the cell (actively or passively), acting as receptors for cell signaling, and recognizing other molecules. Transport can occur by simple or facilitated diffusion via a transport protein due to osmotic pressure. Active transport occurs via a pump powered by ATP or cotransport. Endocytosis (pinocytosis and phagocytosis) and exocytosis (receptor mediated) are other methods of exchange.

If you believe that content available by means of the Website (as defined in our Terms of Service) infringes one or more of your copyrights, please notify us by providing a written notice (“Infringement Notice”) containing the information described below to the designated agent listed below. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as

Please be advised that you will be liable for damages (including costs and attorneys’ fees) if you materially misrepresent that a product or activity is infringing your copyrights. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney.

Please follow these steps to file a notice:

You must include the following:

A physical or electronic signature of the copyright owner or a person authorized to act on their behalf; An identification of the copyright claimed to have been infringed; A description of the nature and exact location of the content that you claim to infringe your copyright, in \ sufficient detail to permit Varsity Tutors to find and positively identify that content; for example we require a link to the specific question (not just the name of the question) that contains the content and a description of which specific portion of the question – an image, a link, the text, etc – your complaint refers to; Your name, address, telephone number and email address; and A statement by you: (a) that you believe in good faith that the use of the content that you claim to infringe your copyright is not authorized by law, or by the copyright owner or such owner’s agent; (b) that all of the information contained in your Infringement Notice is accurate, and (c) under penalty of perjury, that you are either the copyright owner or a person authorized to act on their behalf.

Send your complaint to our designated agent at:

Charles Cohn Varsity Tutors LLC
101 S. Hanley Rd, Suite 300
St. Louis, MO 63105

Or fill out the form below: