Explain Why Are Gradients Important In Diffusion And Osmosis

1. Which dye diffused the fastest in corn syrup? Red Dye In your chosen material? Lemon Concentrate, Blue Dye

Cells and molecules in the environment are constantly moving and changing, for cells to function properly there is a need for equilibrium to be met. The size of the cell and the solution outside of the cell affects the rate of diffusion and osmosis in the cell. Cells are constantly trying to reach an equilibrium with the molecules and substances around it, which is why there are such terms as: hypertonic, hypotonic and isotonic. The procedures allowed testing of whether or not surface area or volume increased diffusion and how different substance control diffusion. Cells are constantly moving to reach equilibrium through diffusion and osmosis.

2. Explain your observations in detail in terms of concentration gradient, diffusion, osmosis, osmotic pressure, passive transport, and active transport.

If the solution in the left beaker contained both urea and albumin, which membrane(s) could you choose to selectively remove the urea from the solution in the left beaker? How would you carry out this experiment?

Increasing the Na+ Cl- concentration in the left beaker while keeping the size of MWCO at 20 would result in an increase in osmotic pressure (Run No.2). This was because the high concentration of Na+ Cl- in the right side of membrane gives a increased force to water (in left beaker) to move towards the solution with the highest concentration of solutes. Therefore, there was an increase in osmotic pressure.

2) When the concentration was at 0.3M, the potato’s cytoplasm and the sucrose solution was isotonic. The concentration of the potato’s cytoplasm was having the same solute concentration as the surroundings. Therefore, there would be no net movement of materials happening.

1. Explain the effect that increasing the Na+ Cl- concentration had on osmotic pressure and why it has this effect. How well did the results compare with your prediction?

6. Describe several adaptations that enable plants to reduce water loss from their leaves. Include both structural and physiological adaptations.

D. Click Play. Do most of the solvent particles move into or out of the cell? (Hint: Does the cell expand or shrink?) ______________________________________________

A major determinant of diffusion in a biological system is membrane permeability. Small, uncharged molecules pass through cellular membranes easily, while most and/or charged molecules cannot pass through the membrane. The movement of water across a selectively permeable membrane, like the plasma membrane

1) The relationship between the rate of diffusion, volume and surface area is that the surface area of a subject somewhat correlates with the volume of the object. When the surface area and volume are set up as a ratio, this gives a good idea as to how fast the rate of diffusion will be. The higher surface area to volume ratio, the faster the rate of diffusion. This is because then there is more surfaces to diffuse through and there materials to diffuse, the rate of diffusion is a lot faster. Conversely, when there is a smaller surface area for more molecules to diffuse through, the rate of diffusion will be lower.

The following hypothesis was made in regard to effect of the concentration gradient on the rate of diffusion: The higher the concentration gradient, the faster the rate of diffusion.

Exercise 1: Cell Transport Mechanisms and Permeability: Activity 3: Simulating Osmotic Pressure Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. Which of the following is true of osmosis? You correctly answered: c. It is a type of diffusion. 2. Which of the following occurs when a hypertonic solution is added to cells? You correctly answered: d. The cells shrink. 3. The variable that affects osmotic pressure is You correctly answered: a. the concentration of nondiffusing solutes. 4. The net movement of water would be into the cell in a You correctly answered: b. hypotonic solution.

(5 pts) 1. Describe the pressure-flow model of translocation in the phloem. Does water move down its

The diffusion of water from the plant into the air lowered the water potential in the outermost cell (mesophyll). The differences of water potential with the adjacent cell will