Investigate the Effect of Temperature on Cell Membranes and Membrane Structure

Aim: The aim of the experiment is to test the effect temperature has on the activity of the enzyme rennin.

As the temperature increases, so will the rate of enzyme reaction. However, as the temperature exceeds the optimum the rate of reaction will decrease.

Add three seeds to the potting mix and cover seeds with little remaining potting mix. After the addition of the potting mix, use a dropper filled with water and water each cell until water drips from the wick. Then place the quads on a watering tray under the fluorescent light bank. Each cell should have an equal distance from the light bank. Quads should be three inches below the fluorescent light; the light should also be left on all day. Make sure all wicks are in contact with the mat that sits on the watering tray. Also watch out for the watering system regularly throughout the experiment. After four to five days record plants in the quads, giving their phenotypes in a table for each cell removed all but the strongest plant.

The Effect of Temperature on the Permeability of Beetroot Membrane Analysis The graph shows the colorimeter readings increase as the temperature increases, they increase by the most at higher temperatures. This is shown by a smooth curve. This means that the beetroot samples release more dye at higher temperatures.

Hypothesis: If the temperature increases, then rate of the chemical reaction will increase as well, and if the temperature decreases, then the rate of reaction will also decrease.

Those cells must receive nutrients and gases in order to undergo the metabolic processes that maintain homeostasis. In paragraph form, explain how you think the nutrients and gases enter the cell. Distinguish between the molecules that can enter by diffusion by simply moving across the membrane and those that must expend energy to cross the cell membrane.

Cell membrane is the barrier that separates the inner environment of the cell from the outer environment. The membrane is selectively permeable.

1) What is the surface area of each of your three cells? The agar cylinder had a surface area of 5.06 cm.

An enzyme is a biological catalyst that speeds up the rate of reaction in certain biological functions. They play a vital role in many aspects of human physiology and are necessary for the functioning of a number of systems, for example in the digestive system to help to break down food. All enzymes have a unique active site that can fit on to a particular molecular arrangement on a target substrate; a substance e.g. carbohydrate, protein, or fat, that the enzyme is designed to breakdown. There are a number of different enzymes in the human body; each type produced specifically to perform a certain role. Enzymes are not themselves destroyed in the reaction to break down a

Water diffuses across the membrane from the region of lower solute concentration (higher free water concentration) to that of higher solute concentration (lower free water concentration) until the solute concentrations on both sides of the membrane are equal. The diffusion of free water across a selectively permeable membrane, whether artificial or cellular, is called osmosis. The movement of water across cell membranes and the balance of water between the cell and its environment are crucial to organisms. ("Diffusion And Osmosis - Difference And Comparison | Diffen"). A semi-permeable membrane known as the cell membrane surrounds the living cells of both plants and animals. Both solute concentration and membrane permeability are taken into account in the ability of a cell to gain or lose water. If there is a higher concentration of solutes in the surrounding solution, water will tend to leave the cell, and vice versa. The membrane forms a selective barrier between the cell and its environment and does not allow toxic substances from the surroundings to enter into the cell (Deena T Kochunni). The selective permeability allows the cell to regulate the flow of necessary substances into and out of the cell. In plants osmosis is also responsible for absorbing water and minerals from the soil by using the semipermeable membrane of the root (Deena T Kochunni). If the extracellular fluid has a lower osmolarity than the fluid inside the cell, it’s said to be

1 - Describe the normal structure and functioning of cell membranes, and explain how they compare to the membranes relating to a specific abnormality in cystic fibrosis?

The diffusion across a cell membrane is a process of passive and spontaneous net movement of small lipophilic molecules. The molecules move from a high concentration to a low concentrated region along the concentration gradient. The result being a point of equilibrium, this is where a random molecular motion continues but there is no longer any net movement. However, there are things that can affect the rate of diffusion, these being temperature, surface area, concentration, size of the molecule, permeability, diffusion distance and concentration difference. Osmosis is a type of diffusion as it is the movement of water molecules through a semipermeable membrane into a region of higher solute concentration. Equilibrium is reached when the solute concentration is equal on both sides. Water potential is measured in kiloPascals, it is the measuring of the concentration of free water molecules that are able to diffuse compared to pure water, which is 0 kilopascals. It is a measure of the tendency of free water molecules to diffuse from one place to another. The result being, the more free water molecules, the higher the Water Potential. However, Water potential is affected by two factors: pressure and the amount of solute.

All cells contain membranes that are selectively permeable, allowing certain things to pass into and leave out of the cell. The process in which molecules of a substance move from an area of high concentration to areas of low concentration is called Diffusion. Whereas Osmosis is the process in which water crosses membranes from regions of high water concentration to areas with low water concentration. While molecules in diffusion move down a concentration gradient, molecules during osmosis both move down a concentration gradient as well as across it. Both diffusion, and osmosis are types of passive transport, which do not require help.

To study the effects of hypotonic, hypertonic and isotonic solutions on plant and animal cells.

Only uncharged, small, polar molecules, (such as water) and hydrophobic molecules, (such as oxygen, carbon dioxide) and lipid-soluble molecules (such as hydrocarbons) can freely pass across the membrane. All ions and large polar molecules (such as glucose) are not permeable to the membrane.