The Discovery of the Cell

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

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. 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

Slide15What do these cells haveIn common?

Slide16“Typical” Animal Cell /~ acarpi/NSC/images/cell.gif

Slide17“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

Slide23Chromosomes• In nucleus • Made of DNA • Contain instructions for traits & characteristics • Usually in the form of long thin threads called  chromatin

Slide24Nucleolus• Small dense region inside nucleus • Involved in the assembly of organelles called ribosomes

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

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

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

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.

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!

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

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

Slide35Cell Wall• Most commonly found in plant cells & bacteria • Supports & protects cells