Podcast
Questions and Answers
The outer cell membrane is also called the ______ or plasmalemma.
The outer cell membrane is also called the ______ or plasmalemma.
plasma membrane
The plasma membrane separates the intracellular fluid from the ______ fluid.
The plasma membrane separates the intracellular fluid from the ______ fluid.
extracellular
The fluid mosaic model depicts the plasma membrane as a ______ of lipid molecules.
The fluid mosaic model depicts the plasma membrane as a ______ of lipid molecules.
bilayer
The most abundant lipids in the plasma membrane are ______.
The most abundant lipids in the plasma membrane are ______.
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Each phospholipid molecule has a polar 'head' and a nonpolar ______.
Each phospholipid molecule has a polar 'head' and a nonpolar ______.
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Sugar groups attached to lipids form ______.
Sugar groups attached to lipids form ______.
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The plasma membrane also contains substantial amounts of ______, which makes the membrane more rigid.
The plasma membrane also contains substantial amounts of ______, which makes the membrane more rigid.
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______ proteins are not embedded in the lipid bilayer and attach loosely to the membrane surface.
______ proteins are not embedded in the lipid bilayer and attach loosely to the membrane surface.
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A network of filaments supports the membrane from its ______ side.
A network of filaments supports the membrane from its ______ side.
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Short chains of carbohydrate molecules attach to the integral proteins to form ______.
Short chains of carbohydrate molecules attach to the integral proteins to form ______.
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The sugars of the membrane’s glycolipids also contribute to the ______.
The sugars of the membrane’s glycolipids also contribute to the ______.
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The glycocalyx is also a distinctive ______ marker.
The glycocalyx is also a distinctive ______ marker.
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Some membrane proteins act as ______ that can bind to molecules.
Some membrane proteins act as ______ that can bind to molecules.
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The plasma membrane is a selectively ______ barrier.
The plasma membrane is a selectively ______ barrier.
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Small, uncharged molecules can pass through the lipid bilayer by simple ______.
Small, uncharged molecules can pass through the lipid bilayer by simple ______.
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The diffusion of water molecules across a membrane is called ______.
The diffusion of water molecules across a membrane is called ______.
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Facilitated diffusion involves molecules moving through a specific ______ protein
Facilitated diffusion involves molecules moving through a specific ______ protein
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Active transport moves molecules against their concentration gradient using ______.
Active transport moves molecules against their concentration gradient using ______.
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Study Notes
Plasma Membrane Structure and Function
- The plasma membrane, also known as the plasmalemma, is a thin, flexible layer surrounding the cell.
- It separates the intracellular fluid (inside the cell) from the extracellular fluid (outside the cell).
- It acts like a security fence, with specific receptors that impact cellular activity.
Fluid Mosaic Model
- The plasma membrane is a phospholipid bilayer, with proteins embedded within it.
- Phospholipids have a polar head (attracted to water) and a nonpolar tail (repelled by water).
- The polar heads face the inner and outer surfaces of the membrane, while the tails point inward.
- The inner and outer layers of the membrane have different lipid compositions.
- Glycolipids (sugar-fats) are found on the outer surface.
- Cholesterol is present, making the membrane more rigid and less permeable to water-soluble molecules.
Membrane Proteins
- Integral proteins are firmly embedded in the lipid bilayer; some are transmembrane proteins spanning the entire membrane.
- Peripheral proteins are loosely attached to the membrane's surface, often forming a supporting network.
- Short carbohydrate chains are attached to integral proteins, forming glycoproteins.
- The glycocalyx is a sugar-covering made up of glycoproteins and glycolipids, providing a unique marker for different cell types.
Plasma Membrane Functions
- Barrier: Protects the cell from external substances and forces.
- Receptors: Membrane proteins bind to external molecules to trigger cellular changes.
- Regulation: Controls what enters and exits the cell; selective permeability.
Membrane Transport
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Simple Diffusion: Small, uncharged molecules (e.g., oxygen, carbon dioxide) diffuse freely across the lipid bilayer.
- Molecules move from high to low concentration.
- Osmosis: Water diffuses across the membrane.
- Facilitated Diffusion: Water-soluble or charged molecules (e.g., glucose, ions) move through specific integral proteins.
- Active Transport: Movement against a concentration gradient, requiring energy.
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Description
Explore the intricate structure and functions of the plasma membrane in this quiz. Learn about the fluid mosaic model, membrane proteins, and the role of phospholipids in cellular activity. Test your knowledge of the critical functions that protect and organize the cell.
