Lesson 1 - Microscopy and Cell Theory.pdf

CHAPTER 1: Structures and Functions of the Cell LESSON 1: Microscopy and Discovery of the Cell OBJECTIVES At the end of the lesson, you should be able to: 1.Trace the development of the microscope; 2.Enumerate the tenets of the cell theory; and 3.Know the contributors of the cell theory....

CHAPTER 1: Structures and Functions of the Cell LESSON 1: Microscopy and Discovery of the Cell OBJECTIVES At the end of the lesson, you should be able to: 1.Trace the development of the microscope; 2.Enumerate the tenets of the cell theory; and 3.Know the contributors of the cell theory. 2 HOW IT ALL STARTED? 3 The Early Microscope ❑Zacharias and Hans Janssen (1597) - Invented the microscope with a maximum of 30x magnification 4 17th – Century Microscopes and the Discovery of the Cell 5 ❑Robert Hooke 6 - observed that cork is composed of small, hollow compartments - The parts prompted Hooke to think of small rooms in a monastery, so he gave them the same name: CELLS. 7 ❑Anton van Leeuwenhoek 8 - Improved magnification of microscopes by polishing lenses - made pioneering discoveries on protozoa (animalcules) , bacteria, red blood cells 9 - From investigating and experimenting with his microscope, Leeuwenhoek became one of the first scientists to refer to living cells when he observed an abundant number of single-celled organisms, which he called animalcules (little animals), swimming in a drop of pond water! 10 The Electron Microscope ❑Ernst Ruska & Max Knoll (1931) - Built the first prototype of electron microscope 11 The Modern Electron Microscope - have greater magnifying power and greater resolution can magnify objects up to 500 000 times their actual size 12  Parts of the Microscope and Their Functions 13 Mechanical Illuminating Magnifying Parts Parts 1. Body tube 1. Mirror 1. Eyepiece or 2. Revolving 2. Condenser ocular nosepiece 3. Iris 2. Objectives 3. Arm 4. Stage diaphragm 5. Stage clips 6. Base 7. Inclination 14 joint M E PARTS FUNCTIONS C Gives support or strength to the H 1. Body tube instrument N I 2. Revolving nosepiece Holds the objectives C Connects the base and the body A 3. Arm tube together L Platform where the slide or 4. Stage P specimen to be examined is placed A R 5. Stage clips Holds the slide in place T Gives support to the whole S 6. Base microscope 7. Inclination joint Used for tilting the microscope I L L U PARTS FUNCTIONS M I Reflects light from the N 1. Mirror surroundings to the specimen A on the stage T I Concentrates the light from N the light source onto the G 2. Condenser object of specimen being P studied A Regulates the amount of light R 3. Iris diaphragm T that reaches the specimen S M A PARTS FUNCTIONS G Part through which an observer looks N 1. Eyepiece or ocular to view the specimen I F Main lenses that magnify the specimen Y being observed I N Typical objectives: 2. Objectives G a. Scanner – 4x b. Low Power – 10x P c. High Power – 40x A d. Oil Immersion – 100X R T OCULAR LENS X OBJECTIVE LENS = TOTAL MAGNIFICATION S Example: 10 x 10 = 100x (100 times larger) Cell Theory ❑Matthias Schleiden 19  Fascinated with plant cells, Schleiden used the compound microscope and studied plant cells. From investigating and experimenting with plants, projected plant parts are made of cells! 20 ❑Theodor Schwann 21  From investigating and experimenting with plant & animal cells, Schwann was able to determine that all animals are made of cells! Schwann published the 1st statement of the cell theory: all living things are made of cells and cell products! 22 ❑Rudolf Virchow 23  Based on his investigations and experiments, he stated that all cells come from preexisting cells, which is the 2nd part of the cell theory: all existing cells areproduced by other living cells! 24  All living organisms are made up of one or more cells THREE TENETS OF Cells comprise the THE CELL smallest functional unit of THEORY life Cells come only from pre- existing cells 25  Cells carry and pass on to the offspring MODERN hereditary units CELL during cell division. THEORY (two additional All cells are relatively key points) the same in terms of chemical composition and metabolic activity. 26  Cell Eye- Contributors Theory catchers Robert Hooke 1. All organisms are 1. Robert Hooke came up with the name cells made of cells. 2. Anton van Anton Van Leeuwenhoek referred to living cells called 2. All existing cells Leeuwenhoek animalcules (plant & animal) after are produced by 3. Matthias observing a drop of pond water Matthias Schleiden other living cells. Schleiden projected plant cells are made of cells 3. The cell is the 4. Theodor Theodor Schwann most basic unit of Schwann determined all animals are made life. of cells (1st statement of the cell theory) 5. Rudolf Virchow Rudolf Virchow stated all cells come from preexisting cells (2nd statement of the cell theory) 27  Size of Cells Smallest cell Mycoplasma Size: 0.1 µm Cells vary in size. Most cells are very small (microscopic), some may be very large (macroscopic). Largest cell The unit used to measure size of a cell is micrometer. Ostrich egg 1 µm = 1 / 1000 Size: 18 cm millimeter  Size of Cells in Humans Smallest cell Largest cell Longest cell Sperm cell Ovum cell Nerve cell Size: 5 µm Size: 120 µm Size: 1 m  Shape of Human RBCs are circular biconcave for easy passage Cells through human capillaries. ▪ Cells vary in shape. ▪ Variation depends Nerve cells are branched to conduct mainly upon the impulses from one function of cells. point to another. ▪ Some cells like Euglena and Amoeba can Human WBCs can change their shape change their shape, but to engulf the most cells have a fixed microorganisms that shape. enter the body. REFERENCES: Rea, M.A., Dequillo, M.Z., and Chua, J.L. General Biology 1: First Edition. 2017. Rex Book Store, Inc. BSCS Biology: A Molecular Approach, 9th Edition. 2006.Glencoe/McGraw-Hill Companies, Inc. https://www.saylor.org/site/wp-content/uploads/2010/11/Wiki-Cell-Theory.pdf https://www.google.com.ph/search?q=microscope+of+robert+hooke&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwikopKv0dv UAhVDKpQKHUhRCiMQ_AUIBigB&biw=1517&bih=681#tbm=isch&q=animalcules+anton+van+leeuwenhoek&imgrc=CeMABtXNhnxbV M: https://www.google.com.ph/search?q=robert+brown+cell+theory&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjD1uLf3dvUAhXEUZ QKHXw1DbEQ_AUICigB&biw=1242&bih=557&dpr=1.1#imgrc=QF77_ezmM5tl3M: https://www.google.com.ph/search?biw=1366&bih=613&noj=1&tbm=isch&sa=1&q=matthias+schleiden+plant+cells&oq=matthias+s chleiden+pla&gs_l=img.3.0.0.87079.88254.0.89613.4.4.0.0.0.0.387.888.0j1j0j2.3.0....0...1.1.64.img..1.3.886...0i30k1j0i24k1.UilTgg0GQ Zc#imgrc=4Pa4K-I1b9bUPM: http://www.csun.edu/~mss70398/Semester%201/Cell%20Theory/Cell%20Theory.html https://www.preceden.com/timelines/46013-contributions-to-cell-theory https://www.google.com.ph/search?q=rudolf+virchow&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwiv-- fH5dvUAhVJipQKHTyhDiMQ_AUIBigB&biw=1366&bih=613#tbm=isch&q=rudolf+virchow+cell+theory&imgrc=rVsNg45DXTxypM: General Biology 1 for Senior High School by Luisito T. 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