Inside the Cell

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  1. The smallest piece of life
    • Cells
    • All organisms are made of cells
  2. Why are cells so small?
    • This is because of efficiency
    • The cell membrane surface area needs to match the volume.
    • If a cell gets too large, there is not enough surface area (membrane) to let everything pass.
    • There would be a higher waste production and the surface area doesn't grow as quickly as the volume.
  3. Characteristics of Prokaryotes
    • Bacteria (and Archaea)
    • Much smaller
    • No defined nucleus (they have a nucleoid)
    • They have ribosomes, plasma membranes, and organelles
  4. How could you tell if something is a prokaryote?
    It is part of a multicellular organism
  5. Characteristics of Eukaryotes
    • Plants, animals, fungi, protists
    • True nucleus
    • More complex than procaryotes
    • Surrounded by a cell membrane
  6. Major difference between procaryotes and eucaryotes?
    Eucaryotic cells tend to have a more extensive inner membrane and a larger number of organelles
  7. Nucleus
    • The command central
    • Holds most of the cell's DNA
    • Surrounded by nuclear membrane
    •  -Nuclear pores control entry and exist
    • Nucleolus-synthesis of rRNA and assembly of ribosome subunits
  8. What maintains the shape of the nucleus?
    Nuclear Lamina
  9. Ribosome
    • The protein factories
    • Complexes of RNA and proteins
    • Carry out protein synthesis
    • Two types: free ribosomes, bound ribosomes
    • Not technically organelles since they are not surrounded by membranes
  10. Free ribosomes
    Make proteins which will function in the cytosol
  11. Bound ribosomes
    Make proteins which will be inserted into membranes or secreted
  12. Which cells have a lot of ribosomes
    • Cells with high rates of protein synthesis
    • Pancreatic cells have a few million ribosomes
  13. What is the endomembrane system composed of?
    • Plasma membrane
    • Nuclear Envelope
    • Endoplasmic Reticulum (Smooth and Rough)
    • Golgi Apparatus
    • Lysosomes
    • Vesicles/Vacuoles
  14. Functions of the endomembrane system
    • Protein synthesis
    • Transport
    • Metabolism
    • Synthesis of lipids
    • Detoxification of poisons
  15. Endoplasmic Reticulum
    • Extensive network of membranes
    • Continuous with plasma membrane
  16. Smooth ER
    • Lacks ribosomes
    • Functions:
    • -Lipid processing
    • -Storage of calcium ions
    • -Detoxification of drugs and poisons
  17. Rough ER
    • Studded with ribosomes
    • Functions:
    • Proteins destined for secretion, shipped to other organelles or embedded in membrane
  18. Which protein would be made in the ribosome attached to the Rough ER?
    A) insulin, which is secreted from the cell
    B) DNA polymerase, which is found in the nucleus
    C) hexokinase, an enzyme that works in the cytoplasm
    D) actin, which is found in the cytoplasm
    A) insulin, which is secreted from the cell
    (this multiple choice question has been scrambled)
  19. Why can you build up a tolerance to drugs and alcohol?
    • If you regularly expose the drug then the body realizes that it needs to break it down, so it expands the smooth ER/
    • This allows the body to break it down more efficiently therefore you need more of it
  20. Golgi Apparatus
    • The post office
    • Modifies, stores and ships proteins
    • - Adds molecular tags (like zip codes) to proteins bound for secretion
    • Stacks of membranous sacs (not physically connected)
    • -products transported by vesicles
  21. Cis face
    Cisternae that is the "receiving" side of Golgi apparatus
  22. Trans face
    Cisternae that is the "shipping" side of Golgi apparatus
  23. Lysosomes
    • Waste management
    • Membranous sac of enzymes that digest macromolecules
    • -Performs phagocytosis and autophagy
  24. Phagocytosis
    • Engulfing solid particles and breaking them down
    • The lysosome releases enzymes to break it down
  25. Autophagy
    • Recycles the cell's own organic material
    • If there is something wrong with a cell like the mitochondria then a lysosome will fuse with it to help recycle the cell
  26. Vacuoles
    • The Handyman
    • Functions:
    • -Food vacuoles (formed by phagocytosis)
    • -Storage
  27. What do vacuoles store?
    • Reserves of important organic compounds
    • Poisonous compounds
    • Pigments
  28. Central Vacuole
    • Plants
    • Stores inorganic ions
    • Allows cells to grow large without increasing cytoplasm
    • Help plants remain rigid
    • Plant cells can get bigger than animal cells since the central vacuole is taking up so much space.
  29. Peroxisomes
    • The Detoxifer
    • Centers for redox reactions
    • Breakdown fatty acids
    • Detoxify alcohol and other toxic compounds
  30. How do peroxisomes break down toxic molecules?
    They use oxidation to produce hydrogen peroxide (H2O2) which is toxic, but they also contain catalase which breaks it down into water and oxygen
  31. What is the most likely pathway taken by a newly synthesized protein that will be secreted by the cell?
    • Ribosomes -> protein is created
    • Rough ER -> proteins are destined for secretion
    • Golgi Apparatus -> modifies, ships, stores proteins
    • Vesicle -> where it fuses with the plasma membrane
  32. Mitochondria
    • The Powerhouse of the Cell
    • Found in almost all eukaryotic cells
    • Double membrane
    • Contains their own DNA and ribosomes (inherited from mom)
    • Site of cellular respiration (produces energy for the cell in the form of ATP
    • Increased mitochondrial density = increased athletic performance
  33. Characteristic of the Mitochondrial double membrane
    • Smooth outer membrane
    • Inner membrane has lots of folds which increases surface area
  34. Chloroplasts
    • The Sugar Factory
    • Double membrane
    • Contains their own DNA and Ribosomes (similar to mitochondria)
    • Contain chlorophyll which is why they appear green
    • Site of photosynthesis
  35. Do plants have mitochondria
    Yes, they contain both chloroplasts and mitochondria
  36. Nuclear Transport
    • Highly regulated
    • Proteins destined for the nucleus has specific amino acid sequence (zip code)
    • -Nuclear localization sequence (NLS)
    • -Nuclear export sequence (NES)
  37. Nuclear Localization Sequence (NLS)
    Made in the cytoplasm and then transported to the nucleus
  38. How do proteins get to their specific locations?
    • All proteins synthesis starts on free ribosomes
    • -Proteins meant for endomembrane system or secretion are marked by a signal peptide
    • -Signal-recognition particle (SRP) escorts the ribosome to the ER membrane
    • -Growing polypepetide snakes across membrane into ER lumen
  39. Exocytosis
    How proteins are secreted
  40. Endocytosis
    • How large molecules are brought into the cell
    • -Receptor-mediated endocytosis
    • -Phagocytosis/pinocytosis
    • The molecules are digested by lysosomes
    • -Building blocks are recycled
  41. Structure of cytoskeleton
    • Maintains cell shape
    • Anchors cellular components
  42. Motility of cytoskeleton
    • Cellular movement
    • Cellular highways
    • -Motor proteins "walk" organelles along cytoskeleton
  43. 3 main types of fibers for the cytoskeleton
    • Microtubules
    • Microfilaments (actin)
    • Intermediate Filaments
  44. Main functions of microfilaments
    • Muscle contraction
    • Cell division (cleavage furrow formation)
  45. Main functions of intermediate filaments
    • Anchorage of nucleus and certain other organelles
    • Formation of nuclear lamina
  46. Main functions of microtubules (tubulin polymers)
    • Cell motility (as in cilia or flagella)
    • Chromosome movements in cell division
Card Set:
Inside the Cell
2017-10-09 01:51:22
Bio Midterm 2
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