Author: Anonymous

Virtual Lab – Operation of Bright Field Microscope What is the total magnification of the observed objects in a microscope that is using the 40X objective lens?

Virtual Lab – Osmosis – Tonicity in Elodea Cells (Plant Cells) Plant cells do not “diminish” in overall size when they lose water due to the presence of a rigid vacuole. 

Virtual Lab – Osmosis – Tonicity in Elodea Cells (Plant Cells) Name three different osmotic environments: [word1], [word2], and [word3] solutions.

Virtual Lab – Microscopy – Animal Cells (Human Epidermal Cells) Locating cheek cells is easier at a lower power objective because it provides a larger field of view, meaning you can see more of the sample at once. This makes it easier to scan a broader area and locate the cells.

Virtual Lab – Osmosis – Tonicity in Elodea Cells (Plant Cells) When the solute concentration is greater on one side of the membrane, the environment with the greater solute concentration is known as the _____________________ environment.

Virtual Lab – Osmosis – Tonicity in Red Blood Cells (Animal Cells) Normal red blood cells have a solute concentration of 1%. When the environment contains 1% solute, the cell is in an isotonic environment. When the environment contains a solute concentration greater than 1%, the cell is hypotonic compared to the environment (the environment is hypertonic).

Virtual Lab – Osmosis – Tonicity in Elodea Cells (Plant Cells) When solute concentration is equal across the membrane, it is known as an ________________ condition.

Virtual Lab – Diffusion Across a Selective Permeable Membrane Why don’t we need to use a strip to test for the presence of starch inside or outside the dialysis tubing?

Molecules move across the selective barrier called the plasma membrane according to their physical and chemical properties. If this process is driven by the potential energy stored in the form of a concentration gradient, it is called passive transport. Passive transport occurs without any additional energy supply by the cell. Molecules move from an area of higher concentration to an area of lower concentration in a process called diffusion. In the first virtual lab activity, we use an artificial membrane called dialysis tubing to mimic the cell membrane. Dialysis tubing is made of cellulose (polymer of glucose) and it acts as a semipermeable barrier much like a real cell membrane. It is selective for which molecules can pass through the dialysis membrane simply based on the size of the pores found in the wall of the membrane. Small molecules will be allowed to pass through while blocking larger molecules.

Virtual Lab – Osmosis – Tonicity in Red Blood Cells (Animal Cells) Correlate each picture to the tonicity (isotonic, hypertonic, hypotonic) 0% NaCl 0.9% NaCl 10% NaCl [word1] [word2] [word3]