Vocabulary Part 1 Solute molecules being dissolved in
Vocabulary Part 1 • • Solute – molecules being dissolved in a solution Solvent – substance doing the dissolving in the solution (usually water) Concentration – amount of solute per unit solvent Diffusion – Movement of molecules (solute) from an area of greater concentration to an area of lesser concentration. • Concentration Gradient – the difference in concentrations across a space or a membrane • Equilibrium – there is no NET movement of molecules across a space or membrane
Vocabulary Part 1 • Permeable – molecules can go through membrane • Selectively Permeable (aka Semipermeable)— movement of molecules is selective based on size, polarity, and charge • Impermeable – molecules cannot go through membrane • Facilitated Diffusion — molecules move down the concentration gradient with the help of a protein in the cell membrane. No energy required. • Active Transport -- molecule uses a protein in the cell membrane to move against the concentration gradient. Energy required.
Vocabulary Part 2 • Osmosis – diffusion of water through a semipermeable membrane. • Hypotonic – less concentrated • Hypertonic – more concentrated • Isotonic – equal concentrations • Plasmolysis – when a cell collapses on itself because it lost too much water • Cytolysis -- when a cell bursts because it has taken in too much water (more common in animal cells…why? )
Vocabulary Part 2 • Turgor Pressure – pressure in a plant cell due to water flowing in • Contractile Vacuole – vacuoles that pump water out of a cell to keep a concentration gradient present. – Example: freshwater fish (is hypertonic to environment). Pumps water out • Water Potential – how much water a solution has. Water will always move from high water potential to low water potential – High Water Potential – a lot of water in a solution, so it is very dilute – Low Water Potential – not a lot of water in a solution, so it is very concentrated
Another Type of Active Transport • way in which a cell takes in big molecules or gets rid of big molecules • Requires energy (ATP) • how some of our immune cells “eat” bacteria • how some of our cells secrete packaged proteins made in the Rough ER • Endocytosis (in) • Exocytosis (out)
Exocytosis
- Slides: 8