3. Movement into and out of cells Flashcards
What is diffusion?
net movement of particles from a region of higher concentration to a region of their lower concentration (down a concentration gradient), due to their random movement
What influences the rate of diffusion?
- temperature
- distance
- surface area
- concentration gradient
What is the concentration of a solution?
How much solute is dissolved in the solvent.
What is osmosis?
net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane
What is active transport? What does it need?
movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration (against a concentration gradient) using energy from respiration
Where does the energy for diffusion come from?
kinetic energy of random movement of molecules and ions
How can substances move into and out of cells?
by diffusion through the cell membrane
What are some roles of water in the body?
digestion, excretion and transport
How does water diffuse through partially permeable membranes?
osmosis
Water _______ by osmosis.
diffuses through partially permeable membranes
How does water move into and out of cells?
by osmosis through the cell membrane
What is turgor pressure?
water pressure inside a plant cell that presses against the cell wall
What does turgid mean?
turgor pressure is sufficient to keep the plant cell stiff
What does flaccid mean?
turgor pressure is insufficient in plant cell due to loss of water by osmosis
What does plasmolysis mean?
plant cell in a concentrated solution, cytoplasm shrinks so much that cell membrane is pulled away from the cell wall
