Biology 1003 - Cells: Size, Structure and Microscopy
What is life? What are the key factors that biologists have defined that apply to every single organism on the planet? In the 17th century, due to the amazing advancement of the microscope, biologists created a theory to differentiate the living from the non-living called the cell theory. One concept from the theory is that all living organisms are composed of one or more cells. The importance of studying cells is akin to the importance of studying life. By being able to observe and experiment will cells, we are further able to understand their function in the environment, in organisms as well as in ourselves. It is the most fundamental unit of life and is responsible for all functions within an organism. There are many different kinds of cells, which pertain to certain life forms on earth carrying out certain specific functions. Cells can be separated into two categories prokaryotes and eukaryotes. Prokaryotes are typically found in unicellular organisms. They do not have a nucleus or nucleus bound organelles. Therefore their DNA, proteins, ribosomes and etc. are enclosed within the cell membrane, without any specific location. They reproduce by the process of binary fission. The two domains of organisms that contain these cells are bacteria and archae. Archae is a unicellular organism that grows in extreme environmental conditions, it is theorized to be the first organisms on the planet. Bacteria are the largest kingdoms of organisms in the world. They grow in several habitats (in soil, in water, in the Earth’s crust, etc.). The second kind of cell is the eukaryotic cell. These cells contain a nucleus as well as nucleus bond organelles (for example; Golgi apparatus, mitochondria, chloroplasts, etc.). Eukaryotes cells exists in four kingdoms; fungi, protists, animals and plants. Funguses are decomposers and are vital for cycling nutrients in the environment. Animals and plants differ in cell structure and function. Animal cells have different organelles (for example; lyzsomes) and an irregular shape. Plant cells also have different organelles (for example; vacuoles and chloroplasts) and rigid cell walls creating a distinct shape. Lastly there is a prosista kingdom, usually containing single cell organisms, which do not have all the characteristics to fit in any other kingdoms. In this experiment, these types of cells were observed and analyzed.
The cells observed in this lab were elodea canadensis (eukaryotic, plant), eptiheial, (eukaryotic, animal), paramecium aurelia (eukaryotic, protist), euglena gracilis (eukaryotic, protist), saccharomyces cerevisiae (eukaryotic, fungi) and staphylococcus aureus (prokaryotic, bacteria). Each cell was examined under a microscope in order to observe certain organelles and movements, which would not be possible to view with the naked eye. Under the 40 magnification, elodea canadensis’ (marine plant) has observable chloroplasts and rigid cell wall structures. Elodea canadensis also has a unique function that can be observed under a microscope called cytoplasmic streaming; this is the flow of the cytoplasm around inner lining of the cellular membrane. Epithelial cells, also known as human cheek cells, have observable organelles. Under the 40 magnification, the irregular shaped cell membrane as well as the nucleus was distinguishable. Paramecium Aurelia (protista found in ponds and swamps) have ciliates that are visible at the 40 magnification. They have the appearance of thin, short hairs that surround the cell membrane (embedded in the pellicle). Its function is to help the motility of this unicellular structure, which observed can be described as pushing the cell forward as the hairs pull back. Euglena gracilis (protista found in ponds and swamps) under a magnification of 40 has an observable flagellum. This long thin protein structure at the end of the cell does a propeller motion, allowing the cell to be...
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