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The Cell Microscopes, History & the Cell Theory. The Microscope ► Originally created for trade purposes ► Merchants needed a way of examining types of.

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Presentation on theme: "The Cell Microscopes, History & the Cell Theory. The Microscope ► Originally created for trade purposes ► Merchants needed a way of examining types of."— Presentation transcript:

1 The Cell Microscopes, History & the Cell Theory

2 The Microscope ► Originally created for trade purposes ► Merchants needed a way of examining types of fibers more closely (i.e., silk, wool, etc) to ensure quality of the product

3 Anton van Leeunwenhoek ► Dutch biologist ► Generally credited w/developing first microscope (early to mid 1600’s) ► Studied never-before-seen living organisms in pond water, blood cells and bacteria ► Called what he saw “animalcules” and “beasties”

4 Robert Hooke ► English scientist ► Examined cork slices and other plant tissues under a microscope ► What he saw were the remnants of dead cells ► He saw box-like structures he called ‘cells’ ► Named them after the rooms in a monastery lived in

5 The Happenin’ 1800’s ► 1824-French scientist Henry Dutrochet says all living things are made of cells ► 1831-Scottish scientist Robert Brown calls the dense round body in the middle of a cell the “nucleus” ► Didn’t know the function of the nucleus

6 The Happenin’ 1800’s: The Big Three ► 1838-German botanist Matthias Schleiden says all plants are made of cells ► 1839-Zoologist Theodor Schwann says all animals are made of cells ► 1855-German Physician Rudolf Virchow says that all cells arise from pre-existing cells ► These guys helped to form the “Cell Theory”

7 The Cell Theory: The modern Version ► 1. All organisms are made up of cells. ► 2. New cells are always produced from pre- existing cells. ► 3. The cell is a structural and functional unit of all living things. ► 4. The cell contains hereditary information which is passed on from cell to cell during cell division. ► 5. All cells are basically the same in chemical composition and metabolic activities

8 The Cell Structure Types of Cells, Examples and Organelles

9 Cell Size Limitations: Think “The Roman Empire” ► Cell size is limited by the: ► The flow of information and materials through the cell ► The cell on the right takes 5 times as long to get info from nucleus to membrane!

10 Two Types of Cells ► Two major categories of cells based upon nuclei  Eukaryotic Cells (Eukaryotes) ► Have a nucleus and membrane-bound organelles  Prokaryotic Cells (Prokaryotes) ► Do NOT have a nucleus ► No internal membrane-bound organelles

11 Eukaryotic and Prokaryotic Cells

12 Eukaryotic Organisms Comprise 4 of the 5 Kingdoms ► Single-Celled Eukaryotes  Kingdom Protista: Protists including Algae  Kingdom Fungi: Yeasts ► Multi-celled Eukaryotes  Kingdom Fungi: Molds, Mushrooms  Kingdom Plante: Plants  Kingdom Animalia: Animals

13 Prokaryotic Organisms Comprise the Kingdom Monera ► Monera include all of the bacteria ► The simple structure of bacteria, and prokaryotic cells in general, make them the most numerous of all the kingdoms

14 Basic Cell Structure Basic Cell Structure ► Three common organelles (little organs) to all Plant and Animal cells: ► Cell Membrane ► Nucleus ► Cytoplasm

15 Cell Membrane ► Present in all cells ► The outer boundary of the cell ► Regulates what enters and exits the cell ► Provides protection and support ► REAL WORLD EXAMPLE: A chain link fence around a city

16 Cell Membrane Structure ► Lipid Bilayer (Composed of Phospholipids- a type of fat) ► Proteins imbedded in the bilayer provide: ► Support ► Channels for molecular transit ► Pumping action for transit ► Carbohydrates on cell surface act as chemical identification for the body

17 Diagram of Cell Membrane

18 Cell Membrane Junctions ► Gap Junctions  Communication ► Tight Junctions  Impermeable ► Desmosomes  Anchoring

19 Nucleus ► The control center of the cell ► Not all cells have nuclei “true” nuclei (think of prokaryotes-i.e., bacteria!) ► The most important part of the nucleus is the DNA inside of it  The genetic blueprint of life

20 Nucleus Structure ► The Nuclear Envelope (also nuclear membrane) ► Two membranes closely held together ► Nuclear pores allow transit in and out of the envelope ► Real world example: Security checkpoints at City Hall

21 Nucleus Structure ► Nucleolus  Consists of the Ribonucleic Acid (RNA) and protein  Ribosomes are made here ► Chromosomes  Elaborate protein “frame” that holds and protects DNA

22 Nucleus Diagram

23 Cytoplasm ► Gel/water-like material between the nucleus and the cell membrane ► Holds all the organelles in place ► Provides a place for chemical reactions to take place

24 Cell Wall ► Found in plants, algae and some bacteria ► Lies outside the cell membrane ► Provides protection and incredible support ► Very porous (lots of holes!) for important molecules to pass through ► Made of multiple layers of different types of carbohydrates including Cellulose-otherwise known as fiber

25 Cell Wall Structure

26 Mitochondria ► Power station (animal cell) ► Takes chemical energy stored in food and converts it to a form the body can use-ATP ► Contains two membranes: ► Outer membrane surrounds and protects ► Inner membrane folds to increase surface area  energy conversion happens here

27 Chloroplasts ► Power station (plant and algae cell) ► Captures light energy from the sun (using chlorophyll) and converts it into chemical energy ► The innermost membrane captures the light energy from the sun

28 Chloroplast Structure

29 Plastids ► Plant organelles w/many forms ► Chloroplasts are one form ► Stores food and pigments ► Leukoplasts  Store food ► Chromoplasts  Store pigments (coloration)

30 Ribosomes ► Makes proteins from amino acids ► Cells that need more protein will have significantly more ribosomes (e.g., muscle cells will have more than skin cells) ► Composed of RNA and proteins ► Membrane-bound or free-floating ► Among the smallest of the organelles

31 Endoplasmic Reticulum (ER) ► Complex network of channels throughout a cell ► Acts as an superhighway within the cell for transport of materials ► Two types of Endoplasmic Reticulum ► Smooth ► Rough

32 Smooth Endoplasmic Reticulum ► Have a smooth appearance (do not have ribosomes attached to them) ► Some cells’ ER hold special enzymes and chemicals for various functions

33 Rough Endoplasmic Reticulum ► Rough due to ribosomes being stuck to the outside ► Involved in making proteins ► New proteins are inserted into Rough ER for transport through the cell

34 Golgi Apparatus ► Discovered by Italian scientist Camillo Golgi ► Resembles a flattened stack of membranes on top of one another ► Located by the cell membrane ► Assists in the collection, modification, packaging and distribution of proteins and other molecules throughout the cell ► The UPS-United Parcel Service of the cell

35 Lysosomes ► The “Cleanup Crew” of the cell ► Small, they contain chemicals and enzymes for digestion ► Involved in cleaning up cell parts, molecules, etc. that have died or outlived their usefulness ► Formed by the Golgi Apparatus ► Also called the “Suicide Sac”

36 Lysosomes ► Conducts the process of endocytosis ► Engulfing of large particles too big to fit through a cell membrane

37 Vacuoles ► Saclike structure that:  Stores water, salts, proteins and carbohydrates ► Found in plant and animal cells ► Vacuole is much larger in plants due to enormous amounts of water being stored ► Builds up water pressure and makes plants sturdy

38 Cytoskeleton ► Cell framework ► Composed of filaments and fibers that help maintain shape, aide in transport, etc. ► Composed of two parts: ► Microtubles ► Mictrofilaments

39 Microtubles ► Hollow tubes made from protein ► Provide support & organelle transport ► Aide in cell division by forming centrioles (animal cells only) ► Support Cilia and Flagella ► Finger-like or whip-like structures that help with: ► Cell movement ► Movement along the cell surface

40 Microfilaments ► Long, thin fibers made of proteins ► Provide: ► Support and movement of cell ► Movement of the cytoplasm (called cytoplasmic streaming)

41 Cytoskeleton Diagram

42 Maintaining a Constant Cell Environment Osmosis & Diffusion

43 Diffusion  The process by which molecules of a substance move from areas of higher concentration of that substance to areas of lower concentration

44 Diffusion ► In the fluid and gaseous state of matter:  Molecules are constantly in motion; colliding with one another and spreading out randomly  This random motion has a general pattern  Molecules move from an area where there are more molecules to where there are less molecules  In other words, they move from an area of higher concentration to an area of lesser concentration.

45 Equilibrium ► The point at which the distribution of molecules and materials are evenly spaced out in any given area.

46 Osmosis ► The diffusion of water across a selectively permeable membrane. ► Some membranes are selectively permeable so some substances cannot pass through or across them (Those substances that “don’t mix well” with the fat in the membrane). ► Water is the exception:  Water doesn’t mix with lipids however its molecules pass very rapidly through the membrane.

47 Osmotic Pressure ► The force exerted by osmosis. ► Tends to move water across a membrane from a dilute solution to a more concentrated solution. ► When solutions are of equal concentration (the desired state) then you have equilibrium and NO movement of water across the membrane.

48 Solution Types Relative to a cell, there are three solution types

49 Hypertonic ► When the solution outside of a cell is of higher concentration than the solution inside of a cell. ► Water will leave the cell in order to dilute the solution outside of the cell.

50 Hypotonic ► When the solution outside of a cell is of lesser concentration than the solution inside of a cell. ► Water will enter the cell in order to dilute the solution inside of the cell.

51 Isotonic ► When the solution outside of a cell is of the same concentration of the solution inside of a cell. ► Water will neither enter nor leave the cell. ► There will be no net movement of water.

52 Solution Pictures

53 Transport Active v. Passive Transport

54 Passive Transport ► Transport of water from areas of higher concentration to areas of lower concentration (either across a membrane or not) that requires NO energy.

55 Facilitated Diffusion ► Deals with the movement of molecules across a membrane that cannot cross a membrane by themselves. ► The channel proteins that facilitate the passage of these molecules are typically specific to that particular substance.  In other words, the proteins have an affinity for whatever substance is dissolved in the solution and will attract it. ► Movement of the substance is reliant upon difference in charge of the molecules and the proteins. ► This process DOES NOT require energy and so is diffusion driven. ► Therefore, there must be a difference in concentration on either side of the cell membrane.

56 Active Transport ► Energy requiring process that moves molecules across a membrane and AGAINST a concentration gradient (from an area of lower concentration to an area of higher concentration).

57 Types of Active Transport ► Pumping action:  “Pumps” move individual molecules across the membrane and against the concentration gradient.  Chemical energy is required to power the pumping action of the protein channel.  Calcium, potassium and sodium are among those substances transported across the membrane. ► Called a “Sodium Potassium Pump”

58 Types of Active Transport ► Endocytosis  Particles “push” against the outside of the cell membrane causing a pocket to form.  This pocket breaks loose on the inside of the cell forming an individual vacuole, or storage structure.  Large molecules, clumps of food and other cells can be taken into the cytoplasm this way. ► Phagocytosis:  A form or Endocytosis where large, solid particles are taken in.  Amebas feed this way. ► Pinocytosis:  When liquid forms pockets along the cell membrane, forms a vacuole and is taken into the cell cytoplasm. ► Exocytosis  When large particles push against the cell membrane from the inside and the membrane surrounds it as it leaves the cell.

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