Chapter 6: Movement In And Out Of Cells Flashcards
What is diffusion?
Diffusion is the movement of molecules, atoms, or ions from a region of high concentration to a region of low concentration, down a concentration gradient.
Give an example of diffusion.
Adding potassium permanganate crystals to pure water. The crystals start to dissolve in water and spread out until evenly distributed, turning the water blue.
Where does the energy for diffusion come from?
The energy for diffusion comes from the kinetic energy of random movements of molecules and ions. Diffusion does not require additional energy.
Where does the energy for diffusion come from?
The energy for diffusion comes from the kinetic energy of random movements of molecules and ions. Diffusion does not require additional energy.
: How does surface area influence diffusion?
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*Answer**: The greater the surface area of the cell, the faster the rate of diffusion. As the surface area increases, more particles can spread out faster.
How does temperature influence diffusion?
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Answer**: High temperature means molecules have more kinetic energy, increasing the rate of diffusion. Temperature is directly proportional to the rate of diffusion
How does distance influence diffusion?
The shorter the travel distance for molecules, the faster the rate of diffusion. Gas diffuses faster through a thin wall than a thick wall.
How does diffusion facilitate gaseous exchange in plants?
Carbon dioxide needed for photosynthesis inside the leaf is in higher concentration outside the leaf. Hence, carbon dioxide diffuses from the air into the leaf through the stomatal openings. Oxygen, a by-product of photosynthesis, diffuses from the leaf to the surrounding air.
How does diffusion support gaseous exchange in animals?
Oxygen is needed for respiration inside all living cells. Oxygen diffuses across the alveoli walls into the blood capillaries down the concentration gradient. Carbon dioxide, a waste product, diffuses into the alveoli.
Define osmosis.
Osmosis is the movement of water molecules from a high water potential to a low water potential through a partially permeable membrane down a water potential gradient.
What is a hypotonic solution?
A hypotonic solution has more free water molecules and fewer solutes than the cell. Water molecules move into the cell.
What is an isotonic solution?
An isotonic solution has the same water potential inside and outside the cell. Water moves across the membrane in both directions, maintaining cell size.
What is a hypertonic solution?
A hypertonic solution has a higher solute concentration and fewer free water molecules than the cell. Water molecules move out of the cell.
Define active transport.
Active transport is the movement of particles (ions/molecules) through a cell membrane from a region of lower concentration to a region of higher concentration against a concentration gradient, using energy from respiration
How do carrier proteins move particles across a membrane during active transport?
The carrier proteins bind to the solute molecule, change shape to carry the molecule across the membrane, and then revert back to their original position.
