microscopy

Description of Investigation

A simple microscope allows the observation of cells and many microscopic organisms and their behaviors in different environments. In this investigation, the process of plasmolysis is observed in onion cells. A hypertonic solution (salty water) to the onion tissue is placed onto it, thus forcing the water out of the cell. As the water comes out of the cell, the cell membrane detaches from the the cell wall. Other

Note: using a microscope camera is very efficient in showing students what they need to see when using their own microscope. Recording and saving images can be even more efficient, but a lot of technique is necessary.

Plasmolysis in Onion Cells
Author(s): Afrodita Fuentes		Microscopy - Teacher's Guide SED 695B
		Microscopy Equipment

Topics addressed cellular structure plasmolysis Hypertonic solution preparation of wet-mount slides microscopy technology	Description of Investigation A simple microscope allows the observation of cells and many microscopic organisms and their behaviors in different environments. In this investigation, the process of plasmolysis is observed in onion cells. A hypertonic solution (salty water) to the onion tissue is placed onto it, thus forcing the water out of the cell. As the water comes out of the cell, the cell membrane detaches from the the cell wall. Other Note: using a microscope camera is very efficient in showing students what they need to see when using their own microscope. Recording and saving images can be even more efficient, but a lot of technique is necessary.
	Materials red/purple onion Scalpel & forceps water 10%-15% salty solution microscope slides and microscope slips microscope microscope camera & software computer

Study Guide: Animal & Plant Cells under the microscope Plasmolysis in Elodea or Onion cells Pond Water Life Observations Pond Water Organisms Identification Guide - pdf Make your own Pond Water organisms Identification poster with - Pond Water Kit
Questions: included in study guide
			Preparing a wet-mount slide of onion cells For microscopic observation,why is it necessary to use only the thin skin of the onion cell? Why use red/purple onion cells and not white onions?
			2 Prepared wet-mount slides of onion cells What cell parts should be identifiable under the microscope?
			Osmotically Balanced Onion Cells under the Microscope Notice the cell at the end of the pointer, its membrane is detaching from the cell wall. What could be causing this?
			Osmotically Unbalanced Onion Cells under the Microscope Plasmolysis in Onion cells. The onion cells have been exposed to a hypertonic solution (salty water). Explain what is happening at the cellular level.

References & Links: http://ebiomedia.com/gall/drop/dropmain.html http://www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/pond/index.html - for pond water organism identification

Plasmolysis in Onion Cells