Students need to put the eggs, after their shells have been removed, in the corresponding jars and leave them for two days. When they return, they must observe and measure the eggs. They suppose to see that the egg in vinegar should be hypotonic, the egg in syrup should be hypertonic, and the egg in distilled water is isotonic. Both jars with vinegar and syrup are independent variables, and the jar with distilled water is the
Apparatus: Weighing balance, beaker 100ml, paper towel/ filter paper, aluminium foil, marking pen, labeling pen, measuring cylinder 100ml and stopwatch Variables: Variables | Method to handle | Independent: The concentration of the sodium chloride solution. | Used different concentration of sodium chloride such as 0%, 5%, 10%, 15%, 20%. | Dependent: The difference in mass of the quail’s egg | Weigh the mass of the quail’s egg using a weigh balance before putting it into the sodium chloride solution and after 24 hours being in the solution. | Controlled: * Type of egg * The type of solution that cover the egg. * Use the same volume of sodium chloride solution.
Introduction All cells have plasma membranes which are selectively permeable meaning only some materials are able to move across it either to enter or exit the cell. The ability of a molecule to cross the plasma membrane depends on its size, hydrophobicity and charge as well as the relative concentration inside and outside of that cell (Biology Department, 2010). When molecules move from high concentration to low concentration it is called diffusion. More specifically when water diffuses across a cell membrane it is called osmosis. If the concentration of water in a cell is lower than the concentration of water in the solute the solution is said to be hypotonic and the cells swell because they will take up water.
Objective Diffusion is the process that occurs when a certain concentrated volume of material moves to a less concentrated state. Osmosis is the movement of a solvent (as water) through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane. Terms for water flow are hypertonic (has low water concentration and high salt concentration than cells), Hypotonic (solution that has high water concentration and low salt concentration than cells), and isotonic (solution that has the same water and salt concentration as the cells). In this lab, we examined the water flow across the selectively permeable membrane of potato cells. We measured the net movement of the potato membrane by comparing the weight of a potato cube before and after incubation in 7%, 14%, 21%, 28%, and distilled water.
The movement of water leads to dramatic changes in the volumes of the two compartments. Osmosis in red blood cells affects the tonicity of the cells. Tonicity refers to the ability of a solution to change the shape or tone of cells by altering the cells’ internal water volume (Marieb 2013). Changes in the concentration of water on either side of the cell membrane result in a net loss or gain of water by the cell (Marieb 2013). If cells are exposed to a solution that has the same solute/water concentration as inside the cells, the solution is said to be isotonic.
BIOLOGY LAB REPORT-OBSERVING OSMOSIS Aim: The aim of the experiment is to observe osmosis by the help of the selective membrane of egg. Osmosis is the diffusion water from an area with a high water concentration to an area with a lower concentration. Research question: What is the effect of in different concentration of solutions with respect to movement of water through egg’s external membrane. Hypothesis: If I put an egg in %30 Salt Solution, because of the different concentration areas egg will get smaller as we increase concentration because water tends to move from high concentrated are to low concentrated area. (Amount of water) Variables: • Dependent Variables: Mass change of eggs • Independent Variables: Concentration amount of solute in water.
Aim : To investigate the average different in mass of five quail’s eggs in five different concentration of sodium chloride solution. Research question : How do the five different concentration of sodium chloride solution affect the average different in mass of five quail’s eggs ? Introduction : In this experiment, we are investigating the effect of osmosis when quail’s egg are immersed in different concentration of sodium chloride solution. “When a cell membrane is said to be selectively permeable, it means that the cell membrane controls what substances pass in and out through the membrane. This characteristic of cell membranes plays a great role in passive transport.
If sugars weren't dissolved, they couldn't reach cells. -Second, the polarity of water is important in repelling nonpolar compounds. Nonpolar compounds don't dissolve well in water (like how oil, a nonpolar solution, forms "beads" in water). This is important to cell membranes in the body. The shape and function of cell membranes depend on the interaction of polar water with nonpolar membrane molecules.
Look in the water bath on your table for a flask labeled DMA. This flask contains Davis Minimal Agar that has been autoclaved to make it sterile, and is being kept at 47 C to keep it liquefied. 3. Think about these important points in pouring a petri plate before doing it: a) You must work quickly, because once the container of minimal agar is removed from the bath, it will start to harden within 2-3 minutes. b) When pouring agar into the petri dish, pour just enough to fill the dish about half way.