The Discovery of the Cell
This chapter delves into the history of cell biology, exploring how the cell was discovered and how our understanding of it has evolved over time. Before the invention of the microscope, cells were invisible to the
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About The Discovery of the Cell
PowerPoint presentation about 'The Discovery of the Cell'. This presentation describes the topic on This chapter delves into the history of cell biology, exploring how the cell was discovered and how our understanding of it has evolved over time. Before the invention of the microscope, cells were invisible to the. The key topics included in this slideshow are . Download this presentation absolutely free.
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Slide1Cell Structure& Function Chapter 7
Slide2The Discovery of the Cell• Without a tool to make them visible cells were until the invention of the microscope • 1665 - Robert Hooke used an early microscope to look at cork cells. • About the same time Anton van Leeuwenhoek observed tiny organisms in pond water. http://www.youtube.com/watch?v=wzI2Rr BYZ5U
Slide3Early Discoveries• 1838 - Matthias Schleiden a German botanist concluded that all plants are made of cells. • 1839 - Theodor Schwann a German biologist stated that all animals are made of cells. • 1855 - Rudolf Virchow a German physician concluded that new cells can only be produced by division of existing cells
Slide4Cell Theory• All living things are made up of cells. • Cells are the basic units of structure and function in all living things. • New cells are produced from existing cells through cell division.
Slide5How do microscopes work?• Most use lenses to magnify the image of an object by focusing light or electrons. • Types of microscopes: – Light microscopes – images 1 millionth of m – Electron microscopes – images 1billionth of m • TEM – transmission – thin samples, can see cell structures & molecules • SEM – scanning – 3-D surface images
Slide6Light Microscope image
Slide7SEM Images
Slide8TEM Images
Slide9Examples of CellsAmoeba Proteus Plant Stem Red Blood Cell Nerve Cell Bacteria
Slide10As you can see cells come in many sizes and shapes
Slide11 All cells have some similarities:• At some point they contain DNA • All cells are surrounded by a thin flexible barrier called a cell membrane or plasma membrane. But they also have differences and so are seperated into 2 broad groups: Eukaryotes and Prokaryotes
Slide12Prokaryotic• Do not have structures surrounded by membranes • Do not separate DNA within a nucleus • One-celled organisms, Bacteria
Slide14Eukaryotic• Contain organelles , specialized structures that perform specific functions; surrounded by membranes • Nucleus separates DNA from the rest of the cell • Most living organisms, great variety Plant Animal http://library.thinkquest.org/C004535/eukaryotic_cells.html
Slide15What do these cells haveIn common?
Slide16“Typical” Animal Cellhttp://web.jjay.cuny.edu /~ acarpi/NSC/images/cell.gif
Slide17http://waynesword.palomar.edu/images/plant3.gif“Typical” Plant Cell
Slide18Cell PartsOrganelles
Slide19Inside the CellTwo major parts
Slide20Cytoplasm• Gel-like mixture also called cytosol • Portion outside the nucleus • Surrounded by cell membrane • Contains organelles of eukaryotes – specialized structures that perform specific tasks
Slide21Nucleus• Directs cell activities • Separated from cytoplasm by nuclear membrane • Contains genetic material – DNA – which contains coded information to make proteins • Prokaryote cells lack a nucleus but they do contain DNA
Slide22Nuclear Membrane• Surrounds nucleus • Made of two layers • Openings called nuclear pores allow material to enter and leave nucleus • Also called the nuclear envelope http://library.thinkquest.org/12413/structures.html
Slide23Chromosomes• In nucleus • Made of DNA • Contain instructions for traits & characteristics • Usually in the form of long thin threads called chromatin http://library.thinkquest.org/12413/structures.html
Slide24Nucleolus• Small dense region inside nucleus • Involved in the assembly of organelles called ribosomes http://library.thinkquest.org/12413/structures.html
Slide25Vacuoles• Membrane-bound sacs for storage of water, salts, proteins, and carbohydrates • Plants usually have a large vacuole that helps maintain shape • Paramecium – contractile vacuole http://library.thinkquest.org/12413/structures.html
Slide26Lysosome• Small organelles filled with enzymes to digest waste • Transports digested material to cell membrane for removal • Also breaks down old organelles no longer needed http://library.thinkquest.org/12413/structures.html
Slide27Cytoskeleton• Helps maintain cell shape and also in movement. • Internal network of protein fibers: • Microfilaments • Microtubules
Slide28Ribosomes• Each cell contains thousands • Make proteins using instructions from DNA http://library.thinkquest.org/12413/structures.html
Slide29Endoplasmic Reticulum• Internal membrane system where compounds are assembled and transported • Smooth ER: lacks ribosomes; makes lipids • Rough ER(pictured): ribosomes embedded in surface; modify proteins made by ribosomes
Slide30Golgi Apparatus• Modifies, sorts, and packages proteins and other materials from the ER for storage in the cell or released outside the cell. • Bundles proteins in tiny vesicles. http://library.thinkquest.org/12413/structures.html
Slide31Mitochondria• Convert chemical energy stored in food (glucose) into compounds that are able to be used by cells – ATP • In humans most all of our mitochondria come from the cytoplasm of the egg cell – so you got yours from your mother. • They also contain their own DNA! http://library.thinkquest.org/12413/structures.html
Slide32Chloroplast• Capture energy from sunlight and convert it into food – sugars – that contain chemical energy in a process called photosynthesis. • Surrounded by two membranes • Contain pigment called chlorophyll http://library.thinkquest.org/12413/structures.html
Slide33Surrounding the Cell
Slide34Cell Membrane• Outer membrane of cell that controls movement in and out of the cell • Double layer • Also known as the plasma membrane http://library.thinkquest.org/12413/structures.html
Slide35Cell Wall• Most commonly found in plant cells & bacteria • Supports & protects cells http://library.thinkquest.org/12413/structures.html