Most aspects of a cell depend on the fact that atoms and molecules have kinetic energy and are constantly in motion. Kinetic energy causes molecules to bump into each other and move into different places.
Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration. Cells have selectively permeable membranes that only allow the movement of certain solutes. Diffusion is vital for many of life’s functions in a cell. It allows oxygen and carbon dioxide exchange in the lungs and between the bodies of intracellular fluid and cells. An example of this process is the diffusion of a smell in a room. Eventually dynamic equilibrium will be reached. This means that the concentration …show more content…
There are many important facts relating to water potential. It is effected by two mechanisms, pressure and solute potential. Water moves from areas of higher water potential (higher free energy and more water molecules) to areas of lower water potential (lower free energy and less water molecules). Water diffuses down a water potential gradient.
Questions 1A
1. Iodine enters the bag because the substance begins to turn a dark purple color and the bag gets bigger. Glucose leaves the bag; we know this because we use a glucose indicator to find out if glucose seeped out.
2. The substances moved and out of the bag, according to the gradient. Some were small substances and moved in and out of the bag quickly and easily. The larger substances, like starch and glucose, were slow or didn’t enter or leave the bag at all.
3. The mass of the bag could be recorded before and after soaking.
4. Water-IKI-Glucose Molecules-Membrane Pores-Starch Molecules
5. Based on the size of the molecules, the glucose and IKI would move out of the bag and the water would go in. The large starch molecules would be left in the beaker.
Questions