6 Questions
What is the main difference between simple diffusion and facilitated diffusion?
Simple diffusion occurs without the aid of proteins, while facilitated diffusion uses proteins in the membrane to transport molecules.
How do protein channels help in facilitated diffusion?
Protein channels allow water-soluble ions to pass by filling a hollow tube.
Explain the concept of water potential in relation to osmosis.
Water potential indicates the solute concentration, and water moves from high to low water potential in osmosis.
What happens to animal cells in hypotonic solutions?
In hypotonic solutions, water moves into animal cells causing lysis (bursting).
Describe the role of ATP in active transport.
ATP provides the energy needed for carrier proteins to pump substances across the membrane selectively in active transport.
How do plant cells respond in hypertonic solutions?
In hypertonic solutions, plant cells lose water and shrink due to the loss of turgidity.
Study Notes
- Simple diffusion is the net movement of molecules from high to low concentration until equilibrium, occurring in liquids and gases due to possessed kinetic energy.
- Facilitated diffusion is a passive process using proteins in the membrane to transport molecules that are polar, large, or not lipid-soluble.
- Protein channels in facilitated diffusion allow water-soluble ions to pass by filling a hollow tube, while carrier proteins change shape to release molecules on the other side.
- Osmosis is the movement of water from high to low water potential through a partially permeable membrane, with water potential indicating solute concentration.
- Isotonic solutions have equal water potential on both sides, hypotonic solutions have higher water potential, and hypertonic solutions have lower water potential.
- In hypotonic solutions, water moves into animal cells causing lysis, while plant cells become turgid due to their cell wall; in hypertonic solutions, cells shrivel up.
- Active transport moves molecules against the concentration gradient using ATP and carrier proteins to pump substances across the membrane selectively.
- The process of active transport involves ATP binding to the protein, hydrolyzing into ADP and Pi to release energy for protein shape change and molecule release.
Test your knowledge on cell transport mechanisms including simple diffusion, facilitated diffusion, osmosis, and active transport. Learn about the movement of molecules across membranes and the different types of solutions affecting cells.
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