THE CELL
TRANSPORT INTO AND OUT OF THE CELL
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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cholesterol.
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lipids.
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proteins.
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nucleic acids.
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Detailed explanation-1: -3. All of the following are found in membranes except: nucleic acids. phospholipids.
Detailed explanation-2: -Nucleic acids are not structural components of cell membranes (ribosomes and nucleus are the main places where they are found). However, being open system, cell exchanges chemicals with its surrounding and cellular membrane can transport nucleic acids as well.
Detailed explanation-3: -So, the correct answer is ‘Lignin’.
Detailed explanation-4: -Four major phospholipids predominate in the plasma membrane of many mammalian cells: phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin. The structures of these molecules are shown in Figure 10-12.
Detailed explanation-5: -Cell membranes are composed primarily of fatty-acid-based lipids and proteins. Membrane lipids are principally of two types, phospholipids and sterols (generally cholesterol).