Large hydrophilic molecules cannot easily cross a plasma membrane due to the presence of which one of the following molecules in the membrane?
A - VCE - SSCE Biology - Question 10 - 2019 - Paper 1
Question 10
Large hydrophilic molecules cannot easily cross a plasma membrane due to the presence of which one of the following molecules in the membrane?
A. proteins
B. choles... show full transcript
Worked Solution & Example Answer:Large hydrophilic molecules cannot easily cross a plasma membrane due to the presence of which one of the following molecules in the membrane?
A - VCE - SSCE Biology - Question 10 - 2019 - Paper 1
Step 1
Identify the reason for difficulty in crossing the membrane
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Answer
Large hydrophilic molecules struggle to cross a plasma membrane because the membrane is mainly composed of a phospholipid bilayer, which acts as a barrier to such polar substances.
Step 2
Determine the role of each option
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Answer
A. Proteins: These can act as channels, helping some molecules pass.
B. Cholesterol: Primarily stabilizes membrane fluidity, not a barrier.
C. Glycoproteins: Have roles in recognition and signaling, not barriers.
D. Phospholipids: Form the main barrier, preventing hydrophilic molecules from crossing.
Step 3
Select the correct answer
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Answer
Based on the above analysis, large hydrophilic molecules cannot easily cross due to the presence of phospholipids.
