Solute: substances that are dissolved in fluid (eg. salt)
Can We Help with Your Assignment?
Let us do your homework! Professional writers in all subject areas are available and will meet your assignment deadline. Free proofreading and copy-editing included.
Solvent: the liquid the solute is dissolved in (eg. water)
movement of materials across a cell membrane without energy; Movement along a concentration gradient
"Be Bold" No-Essay $10,000 Scholarship
The $10,000 “Be Bold” Scholarship is a no-essay scholarship that will be awarded to the applicant with the boldest profile. To us, boldest does not mean “best”, or “most accomplished”. Being bold means being: Earnest, Determined, Moving. The scholarship will be awarded to the student whose profile is most bold, according to these characteristics.
- movement of particles from an area of high concentration to an area of low concentration
- movement will continue until equilibrium is achieved
Example: – Perfume
– CO2 and O2 exchange in lungs
- diffusion of water through a selectively permeable membrane (eg. cell membrane)
- Water moves from higher concentration to lower concentration.
Hypertonic – the concentration of solutes outside the cell is higher than inside the cell.
- water moves out.
Isotonic – the concentration of solutes outside the cell is the same as inside the cell.
Hypotonic – the concentration of solutes inside the cell is higher than outside the cell.
- water moves in.
- this is important to aquatic organisms
- Your kidney uses osmosis to regulate water balance in the blood. This determines the amount of water in urine.
- Molecules too large for simple diffusion use protein carriers in the cell membrane to assist them. They pass through a protein, that acts like a channel in the membrane.
- Substances still move across a concentration gradient. No energy is used!!!!
- Glucose is too large to diffuse through the membrane
- It uses the protein carriers to enter the cell – glucose is constantly being used up in a cell so there is a lower concentration inside the cell.
Active Transport – Using energy to move materials across the cell membrane; materials usually move against the concentration gradient
- Located in nerve cells and critical to their function
- Nerve cells must maintain a higher concentration of Na+ outside the cell and K+ inside the cell.
- Special transport proteins in the membrane pump Na+ out of the cell and K+ into the cell. This takes energy
- moving materials into the cell by pinching the cell membrane
- this forms a vesicle inside the cell
- molecules too large to pass through the cell membrane
Phagocytosis “cell eating”– movement of large molecules
Example: how white blood cells “eat” bacteria
Pinocytosis “cell drinking” – transport of liquids into the cell
- Exporting large molecules outside the cell
- A vesicle inside the cell fuses with the cell membrane and then releases it’s contents outside the cell.
Example: – how insulin is moved out of the pancreas into the blood