Essay on Ap Biology Lab 1 Questions

Osmosis is described in one of three ways when comparing more than one solution. The cell’s external and internal environment helps determine tonicity, which is defined as how the cell reacts to its environment. When the cell’s environment is equal in osmolarity to itself and there is no change, it is considered an isotonic solution. When the environment has a higher osmolarity, shrinkage occurs and it is considered a hypertonic solution. When the environment has a lower osmolarity, swellings occurs and it is considered hypotonic.

2. What do you think would happen if you watered your houseplants with salt water?

This has been shown by a steady increase in Anthon cyanine leaked out of plant cells as the concentration and temperature increases. The purpose of a cell membrane is to control the transport of substances moving into and out of a cell. The membrane is an extremely thin layer (8 to 10 nanometers (nm)) thick, which is partially permeable. It consists mostly of lipids and proteins.

There are 3 potential states that the cell could be in depending on the type of solution:

▪ Surface area to volume ratios and the ability of cells to get nutrients in and waste products out of the cell

Osmosis is the passive movement of water from an area of low solute concentration to an area of high solute concentration, normally across a membrane which prevents the movement of solvent. This is a process by which materials may move into, out of, or within cells. Osmosis doesn’t depend on energy provided by living organisms but is affected by the properties of the cell membrane. The rate of osmosis is dependent on such factors as temperature, pressure, molecular properties such as size and mass, and the concentration gradient. In osmosis, the relationship between a solute’s concentration outside of cell and inside of a cell is described in terms of the tonicity of the solution outside of the cell. A cell is in a hypotonic solution when the solute is more concentrated inside the cell and therefore water moves into the cell. In this solution the cell swells as water enters, this may continue until it ruptures or hemolyzes. In the reverse condition, the cell is in a hypertonic solution

A model cell was made of a visking tube filled with ‘cell contents’. The cell contents represent the cytoplasm of a cell structure membrane. The visking tube represents the plasma membrane of the cell. It acts as a semi-permeable barrier as

Cells are always in motion, energy of motion known as kinetic energy. This kinetic energy causes the membranes in motion to bump into each other, causing the membranes to move in another direction – a direction from a higher concentration of the solution to a lower one. Membranes moving around leads to diffusion and osmosis. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration, until they are equally distributed (Mader & Windelspecht, 2012, p. 50). Cells have a plasma membrane that separates the internal cell from the exterior environment. The plasma membrane is selectively permeable which allows certain solvents to pass through

Plant cells react differently to osmosis than animal cells. When an animal cell is placed in a hypertonic solution, water will leave the cell causing it to shrink, this is known as crenation. When a plant cell is placed in a hypertonic solution the cell membrane will pull away from the cell wall, making the plant flaccid, this is known as plasmolysis. When an animal cell is placed in a hypotonic solution, water will rush in to the cell, causing it to swell and sometimes burst. A plant cell placed in a hypotonic solution will also swell due to water rushing in, but will resist rupturing due to the rigid cell wall. Plant cells become more rigid in a hypotonic solution.

In osmosis, the flow of the water from or to a cell depends on whether the cell is immersed in a solution that is isotonic, hypotonic, or hypertonic to the solution. If the cell is isotonic to a solution, this means that the solute concentration of a cell and its environment is the same and therefore there will be no movement of water. If the solute concentration is lower than that of the cell, then water will flow into the cell, causing it to expand. If the solute concentration is lower than that of the cell then water will flow out of the cell, causing it to shrink.

The purpose of this lab was to demonstrate osmosis and diffusion using model cells. As mentioned, osmosis is when water molecules passively move across a semi-permeable membrane (Russell et al., 2013). In the model cells, the dialysis tubing represents the semi-permeable membrane. Model cell one demonstrates that osmosis occurred because osmosis caused the water to move through the dialysis tubing and into the cell. On the other hand, model cell three showed that a cell would lose water via osmosis in a situation where the solution concentration is higher than the solution in the cell. Model cell one and model cell three both demonstrate that molecules move from high to low concentration. Consequently, this shows that my hypothesis, that osmosis and diffusion will occur between the solutions of different concentration, but not between the solutions of the same concentration, was correct. It is important to note possible errors that may have occurred during this experiment that may have skewed the results. For example, if the string was not tied tight enough around the ends of the model cells the solution inside the cells could have leaked out. This would have skewed the results of the experiment. Model cell two appeared to

All cells have a selectively permeable membrane that controls the movement of materials in and out of the cell. The random movement of the molecules from an area of higher concentration to an area of lower concentration that does not require energy is called diffusion. Through diffusion molecules spread up into the available space until they reach equilibrium. The diffusion of water is called osmosis. Water also moves from the area of higher concentration to an area of lower concentration. The concentration of water is higher when there is less solute, so water moves from an area of lower solute concentration to the area of higher solute concentration.

What is the explanation for the fact that most cells are small and have cell membranes with many convolutions?

Diffusion through cells are able to occur because or its selectively permeable membrane. Diffusion through cells is very vital, for the cell to maintain homeostasis. Homeostasis is the ability of the cell to keep the cell stable. Around the cell there are aqueous solutions, meaning that everything around the cell includes water. The water that is around the cell can move through the cell membrane using osmosis or aquaporin’s. During diffusion the solutes with the higher concentration move to the region with the lower concentration. Cells rely on ATP for diffusion to occur, and without diffusion cells would not be balanced. When the water

When the membrane prevents the particles to pass through, only water will travel by the process of osmosis, and causes a difference in volume of the compartments of the membranes on both sides (Elaine and Mitchell 2015). The process when a cell changes its shape due to a solution is called tonicity. It takes place in three different processes, which is isotonic, hypertonic and hypotonic. In isotonic solution the solution has the same concentration of water, and solute is the same on the inside and out of the cell. Its shape stays the same, and does not takes in or gives out water at all.