Bio Lab Assignment #6-Diffusion and Osmosis

Describe your results from experiment 1. Be very specific in terms of color and size/shape of bag and then solution in beaker.

After the diffusion bag was placed inside the beaker, the fluid inside the beaker turned dark purple and the diffusion bag held inside a medium cadium yellow color.

In which of the following pictures has equilibrium been reached?

Equilibrium was reached on the first image.

_______ is when the cell membrane pulls away from the cell wall You can observe this change by viewing cells under a microscope (Figure 3). The cell membrane will separate from the cell wall and move towards the center of the cell. The cytoplasm and the organelles suspended within it, such as chloroplasts, will move towards the center of the cell.

Plasymosis

When a plant cell is placed in a _____ solution, water leaves the cell. The cell shrinks and becomes ______.

hypertonic;plasmolyzed

The net force driving this transport of water is called the ______.

osmotic pressure.

In Experiment 2, for both trials 1 and 2, net movement of water was from the beaker to the bag. However, the change in mass for the diffusion bag in trial 1 was greater than that for trial 2. Why? Be very specific here.

Due to the fact that the attendance of sucrose was higher in the beaker belonging to the first trial than the one in the second trial , the soultion was much more concentrated.

__________ ________ are barriers that separate the inner contents of the cell from its environment. Cells allow different types of materials to cross the cell membrane. For example, nutrients must enter the cell, whereas waste products must exit.

Cell membranes

______ is the relative concentrations used to determine the direction of osmosis.

Tonicity

For each trial you performed, explain how and why the water moved. Explain all 4 trials for credit.

For trial 1 and 2 , the solution was hypertonic ,whom has a bigger concentration inside the diffusion bag than the beaker. The water exited the cell to balance the concentration. For trial 3, the solution was isotonic, whom has an equal concentration inside the bag and the beaker;therefore, there water does not move. For trial 4 , the solution was hypotonic , whom has a much lower concentration in the bag than the beaker . The water moved inside the cell to balance the concentration.

Initially, Lugol's iodine was placed inside the diffusion bag, and starch was placed outside the bag. Which of these materials was able to pass through the diffusion membrane? How do you know?

The material,The Lugol's iodine ,was able to go past the diffusion membrane due to the liquid inside the beaker turning purple . Moreover, iodine is utilized to test the existence of starch.

How did the Elodea cells change when aquarium water was replaced with hypertonic solution? What caused those changes?

The membranes split apart from the cell wall and shifted in the direction of the middle of the cell. In addition to the membranes separating ,cytoplasm shifted in the direction of the center of the cell as well.Therefore, when the cell shranked ,and when a cell shrinks, it is called "plasmolyzed".

Which material did NOT diffuse across the membrane? Why not?

The starch inside the beaker was unable to spread across the membrane because the membrane only exclusively permits specific molecules to enter or leave without restrictions, due to it being somewhat permeable.

When a plant cell is placed in a _______ solution, water enters the cell. The cell swells and becomes turgid. The cell membrane will be pushed against the cell wall because of the large amount of water entering the cell. The cytoplasm and the chloroplasts will also be pushed towards the cell wall.

hypotonic

When a plant cell is placed in an ______ solution, there is no net movement of water. The concentration of the solutions inside and outside the cell are equal. The cell membrane and the cell wall will rest next to each other. The cytoplasm and chloroplasts will be evenly distributed throughout the cell.

isotonic

An ______ solution has the same concentration as the interior of the cell. A ______ solution has a higher concentration than the interior of the cell. A ______ solution has a lower concentration than the interior of the cell.

isotonic;hypertonic;hypotonic