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Chapter 7 Notes

Chapter 7 Notes. Cell Structure & Function. Section 7-1 ~ Life is Cellular. A. The Discovery of the Cell (pg.169) 1. Early Microscopes: (Tell Who? What Discovered or Used? When?) a. b. In 1665 , an Englishman Robert Hooke used an early compound microscope to look at a

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Chapter 7 Notes

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  1. Chapter 7 Notes Cell Structure & Function

  2. Section 7-1 ~ Life is Cellular • A. The Discovery of the Cell (pg.169) • 1. Early Microscopes: (Tell Who? What Discovered or Used? When?) • a. • b. In 1665, an Englishman Robert Hooke used an early compound microscope to look at a thin slice of cork. Used the term “cell”. In Holland about 1674, Anton van Leewenhoek used a single-lens microscope to observe pond water and found tiny living organisms… even in the water he drank.

  3. 1838, German botanist Matthias Schleiden Concluded that all plants were made of cells. In 1839, German Theodor Schwann stated all animals were made of cells. In 1855, German Rudolf Virchow concluded that new cells could be produced only from existing cells. • 2. The Cell Theory (pg. 170) ~ • a. • b. The Cell Theory States: • 1. • 2. • 3. All living things are composed of cells. Cells are the basic units of structure & function In living things. New cells are produced from existing cells.

  4. Microscopes are always improving. Exploring the Cell pg. 170-171(What is the main idea of this passage?) • Light Microscopy {How does this work? Advantages & Disadvantages?} Light microscopes use light in order to magnify images. Some light microscopes uses laser beams to scan cells for 3 dimensional pictures, produce movies of cells as they grow, divide & develop. Light has limitations with resolution.

  5. Light Microscope Images

  6. Light Microscopy / black widow spider

  7. Light Microscopy / black widow spider eyes

  8. Light Microscopy / diatom

  9. Light Microscopy / radiolaria x10

  10. Laser Scanning Electron Microscope Images

  11. Kingdom: ProtistScientific Name:Amoeba proteusImage Courtesy of: Joanne WhallonImage Width: 30 micronsImage Technology: Laser Scanning Confocal

  12. Kingdom:FungusScientific Name: Saccharomyces cereviceaeImage Courtesy of: Whallon, JoanneImage Width: 24 micronsImage Technology: Laser Scanning Confocal Microscopy

  13. Scanning Electron Microscopes (SEMs) {How does this work? Advantages & Disadvantages?} Electon microscopes use a pencil like beam of electrons to view the surface of specimens. Can view details of a specimen 1000times smaller but the specimen must be in a vacuum and only non-living.

  14. Scanning Electron Microscope Images

  15. Electron micrograph of a mitochondrion in a section from bat pancreas.

  16. The mosquito's head is mostly eye. The eyes of most insects are compound eyes, made up of many tiny lenses. Each lens sees a slightly different picture, making up a mosaic of the object it is looking at. This type of vision is very efficient at noticing very slight motions such as another insect trying to sneak up on it

  17. Flies use their feet for many purposes. The claws can grab to hold on. The small hairs will adhere to smooth surfaces through surface tension. Other hairs are sensory organs, allowing flies to taste with their feet.

  18. Many types of worms have become specialized to live as parasites inside other organisms. This spiny-headed worm uses the spines on its head to attach to the small intestine of a fish. Without a mouth, the worm absorbs nutrients from the fish through its body wall.

  19. Diatoms are tiny single celled plants that live inside a hard shell. They occur in great quantities both in salt and fresh water. When the plant dies, the shell sinks to the bottom. Over time, large quantities of these shells accumulate. They can be collected and used as diatomaceous earth in swimming pool filters. The shells allow water to pass through but trap any small dirt particles.

  20. This cross section of a fern leaf allows us a view of the inside of its cells. The electron microscope reveals many of the cells' structural details not noticeable with the light microscope.

  21. This beautiful vase-like structure is the skeleton of a single-celled organism called a radiolarian. Radiolarians live in large quantities as part of the ocean's plankton. When the radiolarian dies, it's shell sinks to the bottom. After millions of years of radiolarian shells "raining down" on the sea floor, they accumulate in great quantities. Much of the sea floor of the deep oceans are covered in this radiolarian "ooze".

  22. SEM ~ Insect antenna

  23. SEM ~ Bee head

  24. SEM ~ Bee Face

  25. SEM ~ dragonfly head

  26. SEM ~ plant pollen

  27. SEM ~ stem

  28. SEM~ wood

  29. SEM~ Leaf

  30. SEM ~ Tick (parasite)

  31. Transmission Electron Microscopes (TEMs {How does this work? Advantages & Disadvantages?} • Electrons are used to view objects. • Scientists must first cut samples into ultra thin slices for electrons to pass • through. Therefore only non-living specimens may be used.

  32. Transmission Electron Microscope Images

  33. TEM images- Cells / cultured cells

  34. TEM images- Cells / freeze etch yeast

  35. TEM images- Cells / mitochondria

  36. TEM images- Cells / muscle l.s

  37. TEM images- Cells / nerve cell bundle

  38. TEM images- Plant cells / root cell

  39. Scanning Probe Microscopes In the 1990’s a microscope that traces the surface of samples with a probe was perfected. Now we can observe single atoms. They can operate in ordinary air& in solutions.

  40. C. Prokaryotes & Eukaryotes – pg.172-173

  41. III. 7-3 Cell Boundaries pg. 182~All cells are surrounded by a thin, flexible barrier known as a cell membrane~Many cells also produce a strong supporting layer around the membrane known as a cell wall. • A. Cell Membrane • 1. Regulateswhat enters & leaves the cell • 2. Provides protection & support • 3.Composed of a double-layered sheet called a lipid bilayer & contains protein molecules with carbohydrate molecules attached. • 4. These proteins form channels and pumps that help to move material across the cell membrane. Many of the carbohydrates act like chemical identification cards that allows cells to identify one another. • Why would cells need to identify each other?

  42. B. Cell Walls pg. 183 • 1. Present in many organisms, including plants, algae, fungi & many prokaryotes. • 2. Lie outside the cell membrane & made of cellulose; a tough carbohydrate fiber • 3. The main function is to provide support & protection for the cell • 4. Made from fibers of carbohydrate & protein that are produced from within the cell.

  43. C. Diffusion Through Cell Boundaries • One of the most important functions is to regulate the movement of dissolved molecules from the liquid on one side of the membrane to the liquid on the other side. • 2. Diffusion is the process of particles moving from an area where they are more concentrated to an area where they are less concentrated. When the concentration of the solute is the same throughout a solution = equilibrium. • (Because diffusion depends upon random particle movements, substances diffuse across membranes without requiring the cell to use energy. )

  44. D. Osmosis is the diffusion of water through a selectively permeable membrane pg. 185 • 1. How Osmosis Works - Water will move from where it is more concentrated to where it is less concentrated until equilibrium is reached. • When equilibrium = isotonic • In the beginning, more concentration sugar side = hypertonic (above strength) • The diluted or less sugar concentration side = hypotonic (below strength) • 2. Osmotic Pressure is the pressure on the hypertonic side of a membrane

  45. http://programs.northlandcollege.edu/biology/Biology1111/animations/transport1.htmlhttp://programs.northlandcollege.edu/biology/Biology1111/animations/transport1.html

  46. What will happen? Why?

  47. What do you NOW know about the selectively permeable membrane?

  48. E. Facilitated Diffusion (pg. 187) Facilitate = HELP • 1. Happens when a cell membrane’s protein channel helps the diffusion of particles across. Occurs when a molecule that seems too large to pass through a cell membrane is able to get across. • 2. Example: Red blood cells have an internal channel that allows glucose to pass through. • 3. A net movement of molecules across a cell membrane will occur only if there is a higher concentration of that particular molecule on one side than on the other side. This movement does notrequire energyFROM THE CELL. • F. Active Transport pg. 188when a cell moves , materials against a concentration – in the opposite direction & requires energy & carrier proteins within the membrane. • 1. Molecular Transport is when small molecules and ions are carried across the membrane by protein pumps; used to move calcium, potassium & sodium ions. • A considerable amount of our daily energy is devoted to this active transport.

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