Cell notes


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Cell notes

  1. 1. Cell Theory2. Anton van Leeuwenhoek- developed first microscope. a. Dutch biologist5. Robert Hooke- English scientist looked at slices of cork. a. named them cells because they reminded him of small monastery rooms called “cellulae,”9. Robert Brown- 1833 Scottish scientist a. observed dark structure near center- nucleus
  2. 2. 4. Matthias Schleiden- German botanist stated all plants are made of cells, 1838.4. Theodor Schwann- 1839 discovered all animals are made of cells7. Rudolf Virchow- 1855 German physician stated all cells arise from the division of preexisting cells.
  3. 3. 1. All living things are composed of cells2. Cells are the basic units of structure and function3. All cells come from preexisting cells.
  4. 4. 1. Most cells are 5-50 micrometers in diameter. a. Micrometer = one millionth of a meter.3. Eukaryotic cells- contain a true nucleus and membrane-bound organelles. a. Examples: plants, animals, fungi, protists
  5. 5. 1. Prokaryotic cells- have no true nucleus or membrane-bound organelles a. Smaller than eukaryotic cells. b. Examples: bacteria and cyanobacteria5. Eukaryotic cells have 3 basic structures. a. cell membrane, nucleus, cytoplasm.
  6. 6. 1. Regulates what enters and leaves the cell.2. Aids in protection and support of the cell.3. Composed of 2 layers of lipids called- lipid bilayer.4. Peripheral proteins- stick to the surface of the lipid bilayer.
  7. 7. 5. Integral proteins- free-moving and run through the lipid bilayer. a. some form channels that allow certain molecules to pass. b. some act as small pumps that push molecules from one side of the membrane to the other.8. Carbohydrates attach to the proteins and act like chemical identification cards, allowing cells to recognize and interact with each other.
  8. 8. 1. Found in plants, algae, bacteria, fungi,2. Lies outside the cell membrane.3. Helps to protect and support the cell.4. Very porous, water, oxygen, CO2, and other substances can pass through easily.6. Plant cell wall is made up of 2 or more layers. a. 1st layer is made of pectin, holds cells together. b. 2nd layer is called the primary cell wall, made of cellulose. c. Plants with woody stems form 3rd layer called the secondary cell wall, made of cellulose and lignin.
  9. 9. 1. Controls all cellular activity.2. Nuclear Envelope- 2 membranes form the boundary around the nucleus a. contain small openings called- nuclear pores.3. Nucleolus- small region of RNA and proteins inside the nucleus. a. where ribosomes are made.4. Chromosomes- structures made of DNA and proteins that contain the genetic information of the cell.
  10. 10. 1. Cytoplasm- area between the nucleus and the cell membrane. a. contain organelles.4. Mitochondria- change chemical energy stored in food into compounds that the cell can use. a. double layer outer membrane b. Cristae- inner membrane and sight of the electron transport chain where most ATP is made. c. Matrix- space inside the inner membrane where Kreb’s cycle takes place. d. contains it’s own DNA.
  11. 11. 1. Found only in plants and algae.• Surrounded by a pair of membranes.3. Thylakoids- system of membranes arranged as flattened sacs a. Form stacks called grana. b. Light reactions of photosynthesis occur here.7. Stroma- solution surrounding the grana. a. Calvin Cycle of photosynthesis occurs here.5. Contain the green pigment Chlorophyll.
  12. 12. 1. Organelles such as mitochondria and chloroplasts may have once been prokaryotes that existed in a symbiotic relationship with another prokaryote. a. the inner membranes of mitochondria most closely resemble the membranes of bacteria. b. both have their own DNA. c. shaped like bacteria.
  13. 13. 1. Structures in which proteins are made. a. composed of RNA and protein.3. Some are attached to membranes for protein export out of the cell.4. Some are found free in the cytoplasm to produce proteins for the cell itself.6. They are not membrane-bound and are the smallest of organelles.
  14. 14. 1. Manufacturers and shippers of the cell.2. ER- transports materials thoughout the cells. a. Rough ER- covered with ribosomes and makes proteins to be exported from the cell or into cell membrane. b. Smooth ER- not covered with ribosomes, synthesizes steroids in gland cells, regulates calcium levels in muscle cells, breaks down toxic substances in liver cells.
  15. 15. 3. Golgi Apparatus- modifies, collects, packages and distributes molecules produced by the cell. a. appears as a series of flattened sacs. b. discovered by Italian scientist Camillo Golgi.
  16. 16. 1. Small membrane-bordered structures that contain chemicals and enzymes for digesting materials. a. formed by the Golgi apparatus. b. not found in plant cells.5. Involved in breaking down worn-out organelles. a. remove “junk” that might clutter up the cell.3. Used by white blood cells to destroy bacteria.
  17. 17. 1. Vacuoles- saclike structures that store materials such as water, salts, proteins, and carbohydrates. a. Many plants have a single large central vacuole which helps support the cell when full. b. they are smaller and more numerous in animal cells.7. Plastids- plant organelles that have many functions. a. storage of food and pigments. b. leukoplasts store starch granules. c. chromoplasts store pigment molecules.
  18. 18. 1. Composed of a variety of filaments and fibers that support the cell and drive cell movement.3. Microtubules- hollow tubules made of proteins. a. provide support for cell shape. b. help move organelles. c. play a special role in cell division by forming centrioles.8. Microfilaments- long, thin fibers that function in the movement and support of the cell. a. are responsible for cytoplasmic streaming.
  19. 19. 1. Cilia- short, hairlike projections from the cell surface. a. help unicellular organisms move and aid in the movement of substances along the cell’s surface. b. smaller and more numerous than flagella.5. Flagella- long, whiplike structures that help unicellular organisms move about.6. Both contain nine pairs of microtubles arranged around a pair in the center. a. these microtubles are linked to each other, and the bridges that connect them generate the force to produce motion.
  20. 20. 1. Diffusion- molecules move from an area of higher concentration to areas of lower concentration. a. due to the random motion of molecules. b. occurs until equilibrium is reached (conc of the sub is the same on both sides of mem) c. molecules continue to move but in equal amounts.2. Biological membranes are selectively permeable. a. some substances can diffuse through, while others cannot.
  21. 21. 3. Osmosis- Diffusion of water molecules through a selectively permeable membrane. a. Osmotic pressure tends to move water across membranes from a more dilute solution into a more concentrated solution.6. Cells almost always have a much lower conc. of water inside because the cytoplasm is filled with sugars, salts, proteins, etc. a. There should be a net movement of water into a typical cell. b. If this continues the volume of the cell will increase until the cell becomes swollen and bursts like an overinflated balloon. (cytolysis)
  22. 22. 1. Cells deal with osmotic pressure in many ways: a. Some cells never touch fresh water and instead are bathed in fluids such as blood that have conc equal to the cells themselves. (isotonic solution) b. Plants and bacteria have cell walls that prevent overexpanding c. Other cells and unicellular organisms pump out water with contractile vacuoles.6. Hypotonic solutions- low in solute concentration therefore water flows into the cell. (freshwater)7. Hypertonic solutions: high in solute concentration, water flows out of the cell. (saltwater) a. cells shrivel (plasmolysis)
  23. 23. 7. Facilitated Diffusion- transport of materials with the conc. gradient by use of carrier proteins. a. transports larger mol. or those molecules that cannot dissolve in the lipid bilayer. b. fast, specific, and does not require energy. c. Example: glucose-transporter protein helps in the diffusion of glucose into cells.8. Passive Transport- transport of materials that does not require the cell to use energy. a. example: diffusion, osmosis, facilitated diffusion.9. Active Transport- movement of materials against the conc. gradient that requires energy. a. Integral proteins can pump molecules against the gradient, such as calcium, potassium, sodium ions.
  24. 24. 1. Second type of active transport is when large amounts of material are transported through movements and changes in the cell membrane. a. Endocytosis- taking material into the cell by means of infoldings or pockets of the cell membrane. b. Pocket breaks loose and forms a vacuole within the cytoplasm. c. Phagocytosis- taking in of large solids or food. d. Pinocytosis- taking in of liquids. e. Exocytosis- material inside the cell fuses with the cell membrane, forcing the contents out of the cell.
  25. 25. 1. Cells- smallest unit of life.3. Tissues- groups of similar cells that perform a similar funtion. a. four main types: muscle, epithelial, nerve, connective3. Organs- groups of tissues that work together to perform a specific function and help the organ function successfully.11.Organ Systems- group of organs that work together to perform a certain function.