7 Questions
What is the main reason why water moves easily through cell membranes?
Attraction to hydrophilic regions
Which type of movement involves substances passing through a membrane based on size and shape?
Facilitated diffusion
When does diffusion occur?
Without energy requirement
What is the key concept representing the balance between water and solute concentrations in osmosis?
Water potential
In which type of solution do cells tend to swell due to a lower solute concentration outside the cell?
Hypotonic
Which process involves moving substances against the concentration gradient and requires energy input?
Active transport
What role do channel proteins play in facilitating substances through a cell membrane?
Selectively permitting substances based on size and shape
Study Notes
- Cell membranes are selectively permeable structures made of a lipid bilayer with hydrophobic and hydrophilic components.
- Water moves easily through cell membranes due to its unique properties, attracted to hydrophilic regions.
- Channel proteins embedded in the membrane allow only specific substances to pass through based on size and shape.
- Diffusion is the passive movement of substances from high to low concentration along a concentration gradient.
- Diffusion occurs without external stimulation or energy requirement, commonly observed with gases and solutes.
- Facilitated diffusion involves the assistance of channel proteins for substances that are too large to pass through the membrane on their own.
- Osmosis is the passive movement of water molecules through a selective membrane, influenced by solute concentration.
- Water potential is a key concept in osmosis, representing the balance between water and solute concentrations.
- Hypotonic solutions have low solute and high water concentrations, while hypertonic solutions have high solute and low water concentrations.
- Active transport involves moving substances against the concentration gradient, requiring energy input like ATP and specific channel proteins.
Test your knowledge on the structure of cell membranes and various transport mechanisms like diffusion, facilitated diffusion, osmosis, and active transport. Learn how substances move across membranes based on concentration gradients and the role of channel proteins in selective permeability.
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