Eukaryotic Cell

  1. Is the cell the simplest collection of material that can live?
  2. What are the four ideas that summarize the Cell Theory?
    • 1. All living things are made up of cells
    • 2. Cells are the basic unit of life
    • 3. Cells come only from other cells
    • 4. Cells carry genetic info in the form of DNA. This genetic material is passed from a parent cell to a daughter cell.
  3. As the size of the cell increases, the ration of the cell's surface area to its volume ______, and the number of exchanges with the external environment that can occur is ______, since most of the ________ is relatively far from the _______.
    • decreases
    • smaller
    • cytoplasm
    • plasma membrane
  4. What is the typical size of a prokaryotic and eukaryotic cell?
    • prokaryotic: 1 - 10 micrometers diameter
    • eukaryotic: 10-100 micrometers diameter
  5. What are the common methods used to study cells and organelles?
    light microscopy, electron microscopy, cell fractionation, and freeze-fracture.
  6. what is light microscopy?
    • -light focused on a specimen by a glass lens; image is magnified for projection on the eye or photographic film.
    • -may be used to study live cells
    • -use certain dyes or other preparations may kill live specimens
  7. what is electron microscopy?
    • a beam of electron is used instead of light, and electromagnets are used instead of glass lenses. 
    • -prepping specimen for e-micro kills cells so EM cannot be used to study living cells
  8. cell fractionation
    cells whose cell membranes have been ruptured are centrifuged at various speeds for varying lengths of time to separate components of different sizes, densities, and shapes.
  9. freeze fracture
    technique used to study cell membranes and organelles. a frozen specimen is fractured w/ cold knife, producing a fracture plane that generally splits lipid bilayer membranes.
  10. Prok. vs. Eukar. 
    Match: single celled org. 
    multicellular and non bacteria single celled org.
    • Prok. single celled org. 
    • Eukar. multicellular and non bacteria single celled org.
  11. Prok. vs. Eukar., Complexity of structure:
    • Prok: simple cell structure
    • Eukar: Complex cell structure
  12. Prok. vs. Eukar., Genetic material
    Prok: single circular molecule of DNA in the nucleoid region, no histones

    Eukar: genetic material = several linear strands of DNA (chromosomes) coiled around histones
  13. Prok. vs. Eukar., Genetic Material
    Prok: single circular molecule of DNA in the nucleoid region, no histones

    Eukar: genetic material = several linear strands of DNA (chromosomes) coiled around histones
  14. Prok. vs. Eukar., plasmids
    • Prok: contains plasmids which consist of only a few genes
    • Eukar: Do not contain plasmids
  15. Prok. vs. Eukar., Presence/Absence of Nucleus
    • Prok.: No nucleus  
    • Eukar.: nucleus
  16. Prok. vs. Eukar., RNA Processing
    • Prok: Simple RNA processing without splicing
    • Euk: Post-transcriptional RNA modifications: splicing, 5'-cap, poly-A-tail
  17. Prok. vs. Eukar., Location of transcription and translation
    Prok: Transcription and translation occurs simultaneously in cytosol

    Euk: Transcription and translation occur separately in nucleus and cytosol, respectively
  18. Prok. vs. Eukar., Cell division
    Prok: Cell division and asexual reproduction through binary fission

    Euk: Cell division through mitosis and meiosis; sexual reproduction
  19. Prok. vs. Eukar., Presence Absence
    1) cell wall
    • P: Yes
    • E: Plants and fungi have cell wall, animals do not.
  20. Prok. vs. Eukar., Presence Absence cytoskeleton
    • P: No cytoskeleton
    • E: cytoskeleton
  21. Prok. vs. Eukar., Presence Absence
    • P: No centrioles
    • E: Have centrioles
  22. Prok. vs. Eukar., Presence Absence
    membrane bound organelles
    • P: No, lack membrane-bound organelles
    • E: Yes, contain membrane-bound organelle; e.g. mitochondria, chloroplasts, golgi
  23. Prok. vs. Eukar., Site of ATP Synthesis
    • P: ATP production at the plasma membrane
    • E: ATP production in mitochondria
  24. Prok. vs. Eukar.,  Site of respiration
    • P: Respiration occurs at the cell membrane
    • E: Larger multicellular organisms require respiratory systems
  25. What is the plasma membrane responsible for?
    regulating the passage of materials into and out of the cell
  26. what is the fluid mosaic model?
    the plasma membrane consists of a phospholipid bilayer. Meaning phospholipids have both a hydrophilic phosphoric acid region (the head) and a hydrophobic fatty acid region (the tail) amphiatic
  27. How can cells regulate the fluidity of its membrane?
    • - adjusting the amount of unsaturated hydrocarbon tails present in membrane
    • - unsaturated HC tails are bent and do not pack together as closely as saturated HC tails
    • - animals cells can also reg. the fluidity of the cell men. by adjusting the amount of cholesterol present in the membrane.
  28. Where are the hydrophilic region and hydrophobic region found on the membrane?
    hydrophillic (water loving - phospholipid head), facing outside of cell or exterior surfaces of membrane

    hydrophobic (water hating - fatty acid tails), facing inside cell, interior of the membrane.
  29. What is the material contained by the plasma membrane but excluding the nucleus called?
  30. What is the cytosol?
    The fluid component of the cytoplasm, is an aqueous solution containing free protein, nutrients, and other solutes.
  31. What are membrane proteins?
    proteins that are embedded in lipid bilayer membranes that are essential to many cellular activities. they have hydrophobic and hydrophilic regions so the hydrophobia regions passing through the non polar interior of lip. bilayer.
  32. How may a membrane protein be located and and where may it cross?
    • - completely intracellularly
    • - completely extracellularly
    • - anchored to the plasma membrane by a variety of special lipids

    -cross completely through the lipid bilayer, w/ polar areas of protein sticking both into cytoplasm and outside of the cell.
  33. what are membrane-bound organelles and its purpose?
    These organelles are separated from the rest of the cell by a membrane, and each organelle has a specific purpose. 

    Purpose: allows Euk. Cells to compartmentalize activities such as ATP production and consumption in diff. parts of the cell, and control these activities independently.
  34. Name the ___ in the Euk Cell
    • Organelles:1 Nucleolus
    • 2 Nucleus
    • 3 Ribosomes (little dots)
    • 4 Vesicle
    • 5 Rough endoplasmic reticulum
    • 6 Golgi apparatus
    • 7 Cytoskeleton
    • 8 Smooth endoplasmic reticulum
    • 9 Mitochondria
    • 10 Vacuole
    • 11 Cytosol
    • 12 Lysosome
    • 13 Centrioles within Centrosome
    • 14 Cell membrane
  35. What is the nucleus?
    Contains genetic material contained in the nucleus.
  36. What is the nuclear envelope?
    Separates the nucleus from the rest of the cell, consists of two membranes and is perforated (pierced) by nuclear pores.
  37. What are nuclear pores?
    Nuclear pores regulate the passage of Large macromolecules into and out of the nucleus.
  38. What is the nucleolus?
    a dense structure within the nucleus that is the site of the ribosomal RNA (rRNA) synthesis. nucleolus is not surrounded by a membrane.
  39. After assembly, the ____ ____ are exported from the ____  to the ____  , where they will participate in protein synthesis.
    ribosomal subunits, nucleus, cytoplasm
  40. What is the mitochondria?
    • -site of aerobic respiration and site of ATP production within cell. 
    • - powerhouse of the cell
    • -bound by outer and inner phospholipid bilayer membrane.
  41. what does the outer membranes of the mitochondria allow cells to do?
    -outer membranes has pores that selectively allow molecules to enter the cell, depending on their size
  42. What is the intermembrane space of the mitochondria?
    • - the space btwn the outer and inner membranes
    • - high [H+] conc
  43. what is the cristae?
    The inner membrane of the mitochondria which has many convolutions and is also houses the proteins of the electrons transport chain. The inner membrane is embedded with the electron carriers of the electron transport chain.
  44. What is the matrix?
    • -The area bound by the inner membrane is know as the mitochondrial matrix.
    • - site of the citric acid cycle; low H+ concentration
  45. Animal mitochondrion diagram en.svg
  46. What are some characteristics (4) of the mito.  that support the endosymbiotic hypothesis?
    • -Within the cell, mitochondria function semiautonomously (almost by itself)
    • - contain own circular DNA and ribosomes
    • -capable of producing some proteins
    • -genome and ribosomes of mito. are more similar to those of prok. than euk.
  47. What is known as the endosymbiotic hypothesis?
    Mito. are believed to have devel. from early prok. cells that began a symbiotic relationship w/ the ancestors of euk. w/ the mito providing energy and the host cell providing nutrients and protection from the exterior environment.
  48. Why are mitochondria important to the survival of a cell?
    • It produces ATP: 
    • many poisons target the mito. and render it incapable of producing ATP, w/o ATP the cell cannot carry out its metabolic activities, and the cell dies. (note test question: might asked what the effect of a particular drug would have on ATP production)
  49. Is it possible for a person to have different mitochondrial DNA from their mother and father?
    No. A zygote receives all of its organelles from its mother so any mitochondrial DNA a person has is identical to that of his/her mother.
  50. Where are ribosomes synthesized and what are they responsible for?
    • synthesized in then nucleolus and exported to the cytoplasm
    • responsible for protein synthesis
  51. what are the components of the ribosomes?
    • -L and sm subunit
    • -"                   " are composed of rRNA and proteins
  52. Where are free and bound ribosomes found?
    free: cytoplasm, while bound: lie the outer membrane of the Endoplasmic Reticulum (ER)
  53. What are proteins synthesized by free ribosomes destined for?
    proviens destined for the cytoplasm
  54. What are proteins synthesized by the ribosome bound to the Rough ER destined for?
    proteins are destined for insertion into a membrane or secretion outside of the cell
  55. True or false. Prokaryotic ribosomes are larger than eukaryotic ribosomes.
    False. Euk. are larger, prok. are smaller
  56. what is the Endoplasmic reticulum?
    an extensive network of membrane-enclosed spaces in the cytoplasm. The interior of the ER between the membrane is called the lumen and some portions of the ER lumen are continuous with nuclear envelope.
  57. What is the smooth ER?
    • has no ribosomes on its outer surface
    • -is involved in lipid synthesis and detoxification of drugs and poisons.
  58. What is the rough ER?
    has ribosomes on its outer surface and is involved in protein synthesis
  59. Proteins that are secreted or found w/i the membranes are made by ribosomes found where? Where do they go?
    • -on the rough ER
    • - cross the lumen of the rough ER during synthesis. 
    • -sm. regions of the ER bud off to form small membrane bound vesicles that contain newly synthesized proteins.
    • - These cytoplasmic vesicles are then transport to the Golgi Apparatus.
  60. What is the golgi apparatus?
    • -consists of a stack of membrane-enclosed sacs and is usually located between the ER and the plasma membrane. 
    • - vesicles containing newly syn. proteins that bud off from the ER fuse with the golgi apparatus
    • - within golgi, these new proteins are modified and sorted based on their destination. (modification to protein may include the addition of sugar groups to proteins, glycosylation
  61. What is the lysosome?
    -contain hydrolytic enzymes involved in intracellular digestion. The enzymes break down proteins, carbohydrates, and nucleic acids.
  62. What is the contents/ characteristics of the lysosome?
    - maintains a slightly acidic pH of 5 in its interior; this is the pH at which lysosomal activity is greatest. The contents of the lysosome are isolated from the cytoplasm by the lysosomal membrane.
  63. What roles do lysosome play in unicellular organisms?
    essential to the digestion of food particles
  64. What roles do lysosome play in multicellular organisms?
    lysosomes are impt in degradation of foreign products such as bacteria as well as the degradation of damaged cells.
  65. What is the mechanism for the lysosome digestion?
    • -RER synthesizes lysosome's membrane and hydrolytic enzymes
    • -transports vesicle w/ new proteins to golgi complex
    • -golgi syn lysosome meanwhile: food is engulfed by food vacuole by phagocytosis.
    • - lysosome fuses with food vacuole and then digestion occurs.
  66. What is the mechanism for lysosome recycling?
    • -RER synthesizes lysosome's membrane and hydrolytic enzymes
    • -transports vesicle w/ new proteins to golgi complex
    • -golgi syn lysosome  meanwhile there is a damaged organelle floating around
    • -lysosome engulfs damaged organelle by phagocytosis.
    • - recycling occurs.
  67. what are peroxisomes?
    • Peroxisomes contain oxidative enzymes that catalyze reactions in which hydrogen peroxide is produced and degraded. 
    • - break down fats into small molecules
    • -used in the liver to detoxify potentially harmful compounds (such as alcohol)
  68. What would happen if the peroxides produced in the peroxisome if there was a "leak" or dysfunctional peroxisome?
    • would be hazardous to the cell if present in the cytoplasm, since molecules are highly reactive and could covalently alter macromolecules such as DNA. 
    • - compartmentalization of the oxidative reactions w/i the peroxisome reduces this risk.
  69. Which of the following cells would contain the greatest number of ribosomes? 

    B) ribosomes are sites of protein synthesis therefore one would expect a cell that is involved in the production of peptide hormones or enzymes to contain a large number of ribosomes. Only A, pancreatic cell, is involved in the production of both peptide hormones and enzymes, as it produces insulin, glucagon and digestive enzymes.
  70. A damaged organelle would most likely end up here.
  71. What is the cytoskeleton?
    A network of specialized proteins that provides a framework for the maintenance of a cell's shape. 

    also involved in cell movement and the movement of organelles within cell.
  72. What are protein filaments? What 3 types of protein filaments make up the cytoskeleton?
    Basic unit that makes up a cell's skeletal and "muscular" structures. 

    microfilaments, intermediate filaments, and microtubules.
  73. What are microfilaments?
    consist of two intertwined strands of actin (a globular protein). 

    involved in muscle contraction, along with thicker filaments of a protein called myosin.
  74. What are intermediate filaments?
    consist of fibrous proteins could into thicker cables. 

    function in the structural support of a cell.
  75. what are micro tubules?
    hollow rods composed of two types of a globular protein called tubulin, which are involved in the movement of organelles and chromosomes, maintenance of cell shaper, and cell motility.
  76. what are centrioles?
    • only found in animal cells, 
    • are microtubule-organizing centers (MTOCs) that anchor microtubules during mitosis
  77. how are cilia and flagella composed?
    composed of long, stabilized microtubeles arranged in a "9 + 2 structure" 9 pairs of MT surrounding 2 central MT for added stability
  78. What are cilia?
    small structure that move in a whip like fashion with the purpose of moving fluids along a cell surface or propelling a cell within a fluid. 

    line the respiratory tract to move mucus, dead cells, dust, and other particulate matter up towards the mouth for expulsion.

    move in whip-like fashion
  79. what is flagella?
    such as those that give sperm its motility, are similar to cilia in structure but are larger. flagella move in a wave-like fashion
  80. In multicellular organisms, neighboring cells need a way to attach themselves together as well as to communicate w/ another: what are the three types of intercellular junctions?
    tight junctions, anchoring junctions, and gap junctions.
  81. What are tight junctions?
    In tight junctions, the membranes of neighboring cells are attached, and the cells are bound together so tightly that no material can pass btwn cells or travel past the junction. 

    • tight jxn form a total barrier to transport and diffusion. 
    • Ex) intestine, tight junction form a barrier separating the contents of the intestine from the bloodstream.
  82. what are anchoring junction?
    found in animal cell, found in cells subject to mechanical stress. 

    Ex: desmosomes are anchoring jxn that attach epithelial cells in the skin
  83. what are gap junction?
    provide a direct connection between the cytoplasm of one cell and the cytoplasm of a neighboring cell via channels. channels are formed by proteins called connexins. 

    ex) in heart, the flow of ions through gap junctions allows for rhythmic coordinated contraction of the heart muscle.
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Eukaryotic Cell
DAT study cards on Eukaryotic Cell workshop.