Podcast
Questions and Answers
What characteristic of unsaturated fatty acid tails contributes to membrane fluidity?
What characteristic of unsaturated fatty acid tails contributes to membrane fluidity?
- Their high molecular weight increases viscosity.
- The presence of kinks prevents close packing. (correct)
- Their ability to form strong ionic bonds with each other.
- Their saturated nature allows for tighter packing.
Which type of molecule requires assistance from membrane proteins to cross the cell membrane efficiently?
Which type of molecule requires assistance from membrane proteins to cross the cell membrane efficiently?
- Charged ions like sodium ($Na^+$) (correct)
- Small, uncharged molecules like carbon dioxide.
- Small, nonpolar molecules like oxygen
- Large, hydrophobic molecules like steroids
What is the primary role of aquaporins in the cell membrane?
What is the primary role of aquaporins in the cell membrane?
- To transport ions against their concentration gradient.
- To anchor the cytoskeleton to the extracellular matrix.
- To facilitate the diffusion of water across the membrane. (correct)
- To catalyze enzymatic reactions at the membrane surface.
How does the 'fluid mosaic model' describe the structure of the cell membrane?
How does the 'fluid mosaic model' describe the structure of the cell membrane?
What is the role of cholesterol within the cell membrane?
What is the role of cholesterol within the cell membrane?
What distinguishes an integral membrane protein from a peripheral membrane protein?
What distinguishes an integral membrane protein from a peripheral membrane protein?
Which of the following is NOT a major function of membrane proteins?
Which of the following is NOT a major function of membrane proteins?
How do membrane proteins facilitate cell-cell recognition?
How do membrane proteins facilitate cell-cell recognition?
A cell is able to distinguish one type of neighboring cell from another. Which of the following functions of membrane proteins is most likely involved in this process?
A cell is able to distinguish one type of neighboring cell from another. Which of the following functions of membrane proteins is most likely involved in this process?
A researcher is studying a new drug that needs to cross the cell membrane to be effective. The drug is a large, polar molecule. Which mechanism is most likely required for the drug to enter the cell?
A researcher is studying a new drug that needs to cross the cell membrane to be effective. The drug is a large, polar molecule. Which mechanism is most likely required for the drug to enter the cell?
Flashcards
Selectively Permeable Membrane
Selectively Permeable Membrane
A membrane that allows only certain molecules to pass through.
Transmembrane Proteins
Transmembrane Proteins
Proteins that span the entire cell membrane, allowing transport of specific molecules.
Aquaporin
Aquaporin
A protein channel that facilitates the movement of water across a cell membrane.
Peripheral Protein
Peripheral Protein
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Integral Protein
Integral Protein
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Major Functions of Membrane Proteins
Major Functions of Membrane Proteins
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Transport Across Membranes
Transport Across Membranes
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Unsaturated Tails
Unsaturated Tails
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Study Notes
- Selectively permeable membranes are fluid mosaics that are constantly moving
Permeability
- Water needs a channel to travel across the membrane because it is polar
- Aquaporins are channels that let water in and out of cells
Proteins
- Proteins can be built into the membrane
- Hybrid cells have mixed proteins after one hour, such as a human cell mixed with a mouse cell
- Unsaturated tails that are fluid prevent tight packing
- Peripheral proteins are on the surface
- Integral proteins go through the membrane
Membrane Protein Functions
- Transport
- Enzymatic activity
- Signal transduction
- Cell-cell recognition
- Intercellular joining
- Attachment to the cytoskeleton and extracellular matrix
Transport
- Polar or charged molecules require assistance for transport across membranes
- Transport is based on polarity, size, and charge
- Nonpolar molecules, like cholesterol, steroids, and gasses, pass through more easily
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