Questions and Answers
What are integral proteins?
What are peripheral proteins?
Peripheral proteins are not associated with the hydrophobic interior of the lipid bilayer and associate via non-covalent interactions with other membrane proteins or directly with lipid head groups.
What are lipid-linked membrane proteins?
Lipid-linked membrane proteins are anchored in the bilayer by a lipid linkage at the cytosolic surface or the extracellular surface.
What is the fluid mosaic model of the cell membrane?
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What is the function of the cell membrane?
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Polar is hydrophobic while non-polar is hydrophilic.
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What are the learning outcomes related to biological membranes?
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Describe the relationship between membrane physical properties and their chemical composition.
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What are the types of membrane lipids?
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Which type of protein can span the lipid bilayer?
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Cholesterol is a type of __________.
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Study Notes
Integral Proteins
- Integral proteins are amphipathic, possessing both hydrophobic and hydrophilic regions.
- Hydrophobic portions interact with the lipid bilayer's core.
- Can be classified as single-pass or multi-pass transmembrane proteins based on the number of times they traverse the bilayer.
- Single-pass transmembrane proteins cross the membrane once, while multi-pass proteins cross multiple times.
Peripheral Proteins
- Peripheral proteins do not penetrate the lipid bilayer.
- They associate indirectly with the membrane through non-covalent interactions with other proteins or directly with the hydrophilic heads of lipids.
Lipid-Linked Membrane Proteins
- Lipid-linked proteins are anchored to the membrane by lipid attachments at either the cytosolic or extracellular surfaces.
Fluid Mosaic Model
- Represents the cell membrane as a fluid lipid bilayer embedded with proteins.
- Highlights the mobility of lipids and proteins within the membrane.
Function of the Cell Membrane
- Regulates the transport of solutes in and out of the cell, maintaining homeostasis.
Polar vs Non-Polar
- Polar molecules are hydrophilic (water-loving), while non-polar molecules are hydrophobic (water-hating).
Learning Outcomes
- Describing membrane structure and properties (fluid-mosaic model, lipid rafts).
- Explaining the chemical environment's impact on membrane protein structure.
- Understanding factors influencing water movement across membranes.
- Interpreting how ion gradients create membrane potential.
- Differentiating between passive diffusion, facilitated transport, and active transport.
- Outlining the secretory pathway and endocytosis for substance transport.
Structure-Function Relationship
- The physical and chemical properties of membranes are key to their biological functions, necessitating an exploration of their molecular components.
Types of Membrane Lipids
- Phospholipids: Include phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylethanolamine (PE), and phosphatidylinositol (PI); characterized by a hydrophilic head and hydrophobic tails.
- Glycolipids: Feature sugar residues as hydrophilic heads; can be glycerol-based or sphingosine-based.
- Cholesterol: An amphipathic sterol with a unique four-ring structure; influences membrane fluidity.
Types of Membrane Proteins
- Integral Proteins: Span the lipid bilayer, include transmembrane proteins (single-pass and multi-pass types).
- Peripheral Proteins: Interact with the membrane without spanning it; often exposed to the cytoplasmic or extracellular space.
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Description
Explore the key concepts of cell membranes with flashcards focused on integral proteins. Understand their structure, function, and importance in the lipid bilayer. Perfect for students studying cell biology.
