Ms Critchley Science Lichens Project

Task 1 :

Use a light microscope
State why microscopes are useful in the study of cell biology
Calculate total magnification

To calculate magnification the formula you have to do: length of magnified divided by the length of object

The invention of the microscope has opened up a whole new dimension in science. By using microscope scientists were able to discover the existence of microorganisms, study the structure of cells, and see the tiniest parts of fungi, plants, and animals.

Task 2 : Describe the difference between magnification and resolution.

Magnification is the ability to make small objects seem larger, such as making a microscopic organism visible.Resolution is the ability to distinguish two objects from each other. Light microscopy has limits to both its resolution and its magnification.

Task 3 : Describe the advantages and disadvantages of using a light and electron microscope.

Advantage :

Light microscopes advantage is that it can show a useful magnification only up to 1000 to 2000 times.

Electron microscopes have certain advantages over optical microscopes: The biggest advantage is that they have a higher resolution and are therefore also able of a higher magnification (up to 2 million times).

Disadvantage :

Light microscope disadvantages include limited resolution, lower magnification and poorer surface view of the specimen. Compound light microscope require the user to adjust to optical inversion, meaning the specimen will appear to be displaced in the opposite direction it is moved.

Electron microscopes have a range of disadvantages as well: They are extremely expensive. Sample preparation is often much more elaborate. It is often necessary to coat the specimen with a very thin layer of metal (such as gold).

Task 4 : Structures in prokaryotic cells :

The Prokaryotic Cell. Prokaryotes are unicellular organisms that lack organelles or other internal membrane-bound structures . Therefore, they do not have a nucleus, but, instead, generally have a single chromosome: a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid. Bacterial (prokaryotic) cells do not contain a nucleus however Eukaryotic cells do contain a nucleus.

Task 5 : The Comparison between prokaryotic cells and eukaryotic cells :

Prokaryotic –  A prokaryote is a single-celled organism that lacks a membrane-bound nucleus (karyon),                                mitochondria, or any other membrane-bound organelle. Prokaryotes can be divided into                                    two domains, Archaea and Bacteria.

Eukaryotic – An organism whose cells contain a nucleus surrounded by a membrane and whose DNA is                               bound together by proteins into chromosomes. The cells of eukaryotes also contain an                                     endoplasmic reticulum and numerous specialized organelles not present in prokaryotes,                                   especially mitochondria, Golgi bodies, and lysosomes.

Comparison – Both organisms are composed of cells, the basic unit of life, with each cell surrounded by a cell                       membrane. The biggest difference between prokaryotes and eukaryotes is that eukaryotes                              has a nucleus while prokaryotes doesn’t. They also have other membrane structures called                             organelles.