FACULTY OF SCIENCE BSc (Hons) Biotechnology May 2014 Trimester LABORATORY REPORT Unit Code & Title:UDBB1104 Cell BiologyPractical Group:P1 Experiment Title: Cell Structure Date of Submission: 1/7/14 (Tuesday) Instructor:Dr. Kunasundari Balakrishan Declaration Wecertifythatthisreportisofourownworkanddoesnotcontainany unacknowledged work from any other sources. No.NameStudent IDSignature 1Kung Chen Han1401490 2Lim Eng Hang1404630 3Bong Willie1304264 4Eswaran A/L Salwa Singam1401660 Introduction The cell is the fundamental unit of structure and function in living organism. Modern cell theorystatesthatallorganismsarecomposedofcells,andcellisthebuildingblockforall organisms (Schleiden and Schwann, 1839) and that all cells arise only from a pre-existing cells by division (Virchow,1855). The theory is modified as and when new discoveries are made. It stated that each cell is a mass of protoplasm having a nucleus and bounded by a plasma membrane with or without a cell wall and all cells are basically alike in their structure and metabolic activities. This combined views and formulated cell theory is applicable for all living organisms, no matter big or small, simple or complex. (Rastogi, 1997).Cell staining is a technique that can be used to enhance visualization or observation of cells and cell components under a microscope. We can differently stain certain cell components, such as a nucleus or a cell wall, or the entire cell by using different stains. The choice of stains is important because certain stains are specific to certain structures. Most stains can be used on fixed, or non-living cells, while only some can be used on living cells; there are also some stains can be used on both living or non-living cells. Cells may also be stained to highlight metabolic processes or to differentiate between live and dead cells in a sample. (Bruckner, 2013). For example, iodine can used to stain the starch grains since it is a starch indicator. When in solution, the starch grains turns dark blue/ blue black colour. Objectives 1.To prepare specimens for staining. 2.To identify unique and standard structures of the microscopic world. 3.To identify and use different stains for the different types of organelles. Results Epidermal Cells of Plants TitleLower Surface of Rheo discolours leaf Magnification Power: 10 10 TitleLower Surface of Rheo discolours leaf Magnification Power: 10 40 Cell wall Guard cell Guard cell Stoma Cell wall TitleUpper Epidermis of Rheo discolours leaf Magnification Power: 10 10 Yeast Cells (Saccharomyces) TitleYeast in Sucrose Solution smear Magnification Power: 10 10

Nucleus Cell wall Yeast cell Yeast cell budding Blood Cells TitleHuman Blood smear Magnification Power: 10 10 TitleHuman Blood smear Magnification Power: 10 40 Erythrocytes (Red blood cells) Leukocyte (White blood cell) Erythrocyte (Red blood cell) Leukocyte (White blood cell) Spirogyra Cells TitleSpirogyra scalari form conjugation w.m. Magnification Power: 10 10 TitleSpirogyra scalari form conjugation w.m. Magnification Power: 10 40 Cell wall Zygospore Cell wall Zygospore Flagellum Title: Euglena w.m. Magnification Power: 10 10 Title: Euglena w.m. Magnification Power: 10 40 Contractile vacuole Plasma membrane Nucleus Chloroplast Euglena cell Flagellum Discussions and Answering Questions Epidermal Cells of Plants A group of epidermal cells of plantform one cell thick layer that cover the entire parts of plant, including the leaves, flowers, stems and roots, as a boundary between the plant and external environment.(Forbes, Watson, 1992). Based on the observation obtained, the nuclei is seen more readily in the upper epidermis due to the Iodine stain used. The iodine stain creates a better contrast in order to visualize the nuclei of the epidermal cell under the microscope. While for the lower surface of the epidermal cell the dye used to mount the sample is Eosin. The structure of lower surface of the epidermal cell is different compared to the structure of upper epidermis. The lower epidermisseemstocontainguardcellswhichareabsentintheupperepidermis.Thelower epidermis also contains green plastids around the guard cells. The guard cells that contain these plastids are present in a pair of crescent-shaped. Yeast Cells (Saccharomyces) Yeast is a microscopic unicellular fungus which grows naturally on the surface of fruits. Most yeast reproduce asexually by mitosis, and many do so by an asymmetric division process called budding, whereby a yeast cell grows and divides into two daughter cells that each contain the identical information and machinery necessary to repeat the process. According to Walker (1998), the budding process starts when mother cells grow to a critical size at a time corresponding with the onset of DNA synthesis, followed by the weakening of the cell wall together with the pressure exertedtoallowextensionofcytoplasminanareaboundedbynewcellwallmaterialswhich synthesizedbyenzymessuchaschitinsynthetases.Thenthechitinformaringatthejunction between the mother cell and the bud eventually contract to separate the bud from mother cell. Yeast resembles a basic plant cell in having a cell wall made of fungal cellulose. While it also contains centrioles which are not there in plant cells but are present in animal cells. Yeast cell does not contain any chloroplast which is also absent in animal cells. The common features between yeast, plant and animal cells are the presence of plasma membrane enclosing the cytoplasm , nucleus, ribosomes and mitochondria. Blood Cells Wehadexaminedthewhitebloodcellsinapreparedsmearofhumanblood.The granulocytes move by amoeboid locomotion and engulf bacteria by phagocytosis. These cells travel in the blood stream, delivered by blood to the infection sites or sites of tissue disruption, work to defendthebodyfrominfectingorganismsbyphagocytesthebacteria.Themostabundant populationofbloodcellsisredbloodcells(erythrocytes).Theycontainhemoglobinthat responsible for carrying oxygen to body tissues and take up carbon dioxide from tissues as waste on the other hand. (Rhoades, Bell, 2009). Red blood cells are smaller than white blood cells or other typical animal cells. They have a fixed round, biconcave disc shaped, compared to the irregular shapes of white blood cells. Different from the typical animal cells, red blood cells do not have nucleus within the cell body. Spirogyra Cells Spirogyraisatypeofgreenalgaecommonlyfoundinfreshwaterhabitat.Basedon observation, we are able to identify the zygospore. The cell wall is visible due to the staining of the cell with methylene blue. However we are unable to view any organelles in the spirogyra. The aid of figure 1.1 is needed in order to explain the organelles present in the spirogyra cell. (Figure 1.1: The labelled diagram of a spirogyra cell) Retrieved from: http://cronodon.com/images/Spirogyra_diagram_labeled.jpgThe chloroplasts are commonly arranged spiral ribbons that seem to curl up the filaments of the colony. Along the ribbons of the chloroplasts are small round nodules which are the pyrenoids, the center making starch. The cellulose cell walls are often lined up with cytoplasm surrounding a vacuole.Inthecenterofthisspaceisthenucleus,suspendedbystrandsofcytoplasm.From diagram1.1,T.S.Filamentshowsthearrangementofthecytoplasmandvacuole.Thethree-dimensional shape of the spirogyra cells would be long chain made up of rod sections. Under the microscope, the cell wall of the spirogyra would be colourless and non-visible to the eyes. The outline of the cell wall is made visible when the spirogyra cell retains the methylene blue dye. Cell wallistheoutermostprotectivedoublelayerstructure.Theinnerlayerofwhichismadeof cellulose and the outer layer contains pectose. The outermost lining of Pectose turns into Pectin and get dissolved in water to form Mucilage which surrounds the filament and forms Mucilagenous sheath. Mucilage is a type of soluble fiber of viscous nature. It is produced from the seeds of certain plants, such as carob bean, plantain, flax or mustard. Mucilages have different functions. Among the most important ones, we can point out: 1.Protection of plant wounds, they create a gummy or gelatinous layer on wounds that can prevent microorganism to go into the plant tissue. 2.Germination of seeds. Upon contact with water, they increase volume and maintain a layer of moisture around the seed that facilitates their germination. 3.Seed dispersal. Some root mucilage used to promote the introduction of them into ground. The comfrey is a clear example of how a component can produce this result. Sometimes these secretions are a weapon to catch prey, such as occurs with the mucilage secreted by the carnivorous plants. Flagellum According to the study by Prof. Kotpal (2012), Euglena is a single-celled small organism in the Protist Kingdom, usually found in quiet fresh and salt waters. It is eukaryotic cell because it has a round bounded nucleus as we seen under the microscope. Under high power magnification, we had seen the chloroplasts within the cell body, it indicates that Euglena was feed by autotrophy like plant using photosynthesizing chloroplast. However, we had also observed the contractile vacuole structure inside the cell body, it proved that Euglena are not completely autotrophic like plants, but they also can phagocyte or consume food like animals and form vesicle or vacuole within the cell body (heterotrophic). It has a whippy tail called a flagellum on the front end of cell body that will twirls to pull the cell, allows it to move through the water. References Rastogi, V.B. (1997). Cell Theory. Modern Biology, pg. 144-146. Pitambar Publishing. Bruckner, M.Z. (2013). Basic Cellular Staining. Microbial Life Educational Resources. Retrieved from http://serc.carleton.edu/microbelife/research_methods/microscopy/cellstain.html Walker, G.M. (1998). 4.2 Cellular Growth of Yeasts. Yeast Physiology and Biotechnology, pg. 102-106. J ohn Wiley & Sons. Rhoades, R., Bell, D.R. (2009). Chapter 9: Blood Components. Medical Physiology: Principles for Clinical Medicine, pg. 175-181. Lippincott Williams & Wilkins. The labelled diagram of a spirogyra cell. Retrieved from: http://cronodon.com/images/Spirogyra_diagram_labeled.jpgProf. Kotpal, R.L. (2012). Chapter 3: Euglena viridis. Modern Text Book of Zoology: Invertebrates, pg. 30-39. Rastogi Publications. Forbes, J .C., Watson, D. (1992). 4.5 Protective Tissues of Plants. Plant in Agriculture, pg.94. Cambridge University Press.