4.1.3 Transport in Cells Flashcards
(17 cards)
what is diffusion?
the net movement of particles from an area of high concentration to an area of lower concentration
what three main factors affect the rate of diffusion
concentration gradient-larger gradient ,faster diffusion
temmperature-higher teperature,faster diffusion
surface area-larger surface area, faster diffusion
give examples of substances transported by diffusion in the lungs and the kidney
lungs-oxygen diffuses into the blood from the lungs and carbon dioxide diffuses into the lungs from the blood,both down their concentration gradient
kidney-urea diffuses from cells into blood plasma so it can be excreted in urine
what is osmosis
the net movement of water moleculues from an area of high water concentration to an area of low water concentration through a partially permeable membrane
what is meant when a solution is isotonic to a cell
the concentrations of the external and internal(inside cell) solutions are the same
what is meant when a solution is hypertonic to a cell
the concentartion of the external solution is higher than that of the internal solution (inside cell)
what is meant when a solution is hypotonic to a cell
the concentarion of the external solution is lower than that of internal solution(inside cell)
what may happen when an animal cell is placed in a hypotonic solution
water moves into the cell causing it to burst
what may happen when an animal cell is placed in a hypertonic solution
water moves out of the cell causing it to shrivel up
what is active transport
the movement of molecules against a concentration gradient(high to low concentration)
how do plants root hair cells use active transport
root hair cells use active transport to take up mineral ions from a more dilute solution in soils .
Describe how you would carry out an investigation into osmosis using potato tissue.
Cut identical potato cylinders using a cork borer
Measure and record the length and mass using a ruler and balance
Add each cylinder to one of three solutions: 1M sugar solution, 0.5M sugar solution, and distilled water
Leave cylinders in tubes overnight
Remove and blot cylinders with paper towels
Record the length and mass again
Draw a graph of change in mass (g) vs. concentration of solution (mol/dm³)
Why is it necessary to use a cork borer to cut the cylinders?
Results in equal-sized samples so changes in length and mass can be compared easily.
Why is it necessary to blot the cylinders with paper after removing them?
To remove surface water that varies between samples, ensuring masses are comparable.
What variables should be controlled in the osmosis experiment?
Temperature
Volume of solution
Time cylinders are left in the solution
Size and surface area of potato cylinders
What is the dependent variable in the osmosis experiment?
The change in mass (or length) of the potato cylinders.
What is the independent variable in the osmosis experiment?
The concentration of the sugar solution.
