Cells: The Living Units

The flashcards below were created by user rloong on FreezingBlue Flashcards.

  1. Robert Hooke
    • is the "father of microscopy" 
    • it was Hooke who coined the term "cell" to describe the basic unit of life
    • 1st observed a plant cells (cork) with a crude microscope in the late 1600s
  2. Matthias Schleiden and Theodor Schwann
    • 1830s
    • boldly asserted that all living things are composed of cells
  3. Rudolf Virchow
    cells arise only from other cells
  4. Human Cells have 3 main parts
    • 1. the plasma membrane
    • 2. the Cytoplasm
    • 3. the nucleus
  5. Integral Proteins
    are firmly embedded in or strongly attached to the lipid bilayer
  6. Peripheral Proteins
    • are not embedded in the lipid bilayer at all
    • they attach rather loosley to the membrane surface
  7. Transmembrane Protein
    span the whole width of the membrane and protrude from both sides (trans = across)
  8. Diffusion
    • is one result of the movement of molecules (High concentration → Low Concentration)
    • is passive transport, does not require energy
    • Ex. Oxygen, Carbon, Fat-soluble molecules can pass freely through the lipid bilayer of the PM
  9. Osmosis
    the diffusion of water molecules across a selectively permeable memebrane
  10. Facilitated Diffusion
    Diffusing through the plasma membrane by moving through a specific integral protein
  11. Active Transport
    • other integral proteins move molecules across the PM against their concentration gradient
    • requires energy
  12. Endocytosis
    is the mechanism by which large particles and macromolecules enter cells
  13. Vesicle
    deforms the membrane to form a membrane-walled sac
  14. Three types of endocytosis are recognized:
    • Phagocytosis
    • Pinocytosis
    • Receptor-mediated endocytosis
  15. Exocytosis
    is a mechanism by which substances move from the cytoplasm to the outside of the cell
  16. Cytoplasm
    • "cell forming material"
    • is the part of the cell that lies internal to the plasma membrane and external to the nucleus
  17. There are three major elements that make up the Cytoplasm:
    • 1. Cytosol
    • 2. Organelles
    • 3. Inclusions
  18. Cytosol 
    • is the jellylike, fluid containing substances within which the other cytoplasmic elements are suspended
    • made up of water, ions, and many enzymes
    • in many cells, makes up half the volume of the cytoplasm
  19. The cytoplasm contains nine types of organelles:
    • Mitochondria 
    • Ribosomes
    • RER
    • SER
    • Golgi Apparatus
    • Lysosomes
    • Peroxisomes
    • Cytoskeleton
    • Centrioles
  20. Ribosomes
    • Protein Synthesis
    • constructed of proteins plus ribosomal RNA
    • not membrane bound
  21. Central Dogma of Molecular Biology
    • DNA→RNA→mRNA→protein
    • DNA→RNA = Transcription
    • RNA→mRNA = Post Transcripted Modification
    • mRNA→Protein = Translation
  22. Endoplasmic Reticulum
    • is literally the "network within the cytoplasm"
    • is an extensive system of membrane-walled envelopes and tubes that twists through the cytoplasm
  23. Free Ribosomes
    • float freely within the cytosol
    • make the soluble proteins that function in the cytosol itself
  24. Messenger RNA (mRNA)
    genetic material in the cell nucleus (DNA), whose instruction are carried to the ribosomes by messenger molecules
  25. Golgi Apparatus has 3 pathways:
    • A. the protein product is contained in secretory vesicles; these vesicles ultimately release their contents to the cell's exterior by exocytosis
    • B. the membrane of the vesicle fuses to and contributes to the plasma membrane
    • C. the vesicle leaving the golgi apparatus is a lysosome, that remains inside the cell
  26. Lysosomes
    • are spherical, membrane-walled sacs containing many kinds of digestive enzymes
    • enzymes called acid hydrolase, can break down almost all large biological molecules
    • AKA "demolition crew", because they break apart and digest unwanted substances
  27. In the addition to morphology, cells differ in:
    • there ability to move
    • their internal organization (prokaryotic vs eukaryotic)
    • their metabolic activities
  28. How many distinct cell types make up the human body?
  29. Zygote
    • Sperm + Oocytes = Zygote
    • Zygote→Blastocyte (hollow ball)
  30. All living things fall into two categories:
    • Prokaryotic: only domains: bacteria and archaea
    • Eukaryotic cells: Plant and Animal kingdoms, including the fungi
  31. Prokaryotic
    consists of a single enclosed compartment that is surrounded by a plasma membrane, lacks a defined nucleus, and has relatively simple organization
  32. Eukaryotic
    • contain a defined membrane-bound nucleus, the nucleus segregates the cellular DNA from the rest of the cell
    • can be either unicellular or multicellular
  33. Osmoregulation
    is the control of water balance in animals
  34. Ribosomes build all the cell's proteins through a process called?
  35. Antibiotics target
    • the processes of ribosomes
    • kills bacteria by stopping the protein they need in order to survive
  36. Isotonic Solution
    • equal concentration of ions in solution and cell
    • equilibrium 
  37. Hypertonic Solution
    • High concentration of ions in solution than in cell
    • Solvent will go out of cell, cells will shrivel/shrink
  38. Hypotonic Solution
    • Lower concentration of ions in solution than in cell
    • solvent will go into cell, cells will enlarge
  39. Cytoskeleton
    • "Cell Skeleton"
    • is an elaborate network of rods running throughout the cytosol
    • Supports the cell's structures and generates various cell movement
    • not membrane bound
  40. Three types of rods in the cytoskeleton:
    • 1. Microfilaments
    • 2. Intermediate Filaments
    • 3. Microtubules
  41. Microfilaments
    the thinnest elements of the cytoskeleton, are strands of protein actin
  42. Intermediate Filaments
    are tough, insoluble protein fibers, with a diameter between those of microfilaments and microtubules
  43. Microtubules
    the elements with the largest diameter, are hollow tubes made of spherical protein subunits called tublins
  44. Centrosome
    • is a spherical structure in the cytoplasm near the nucleus
    • not membrane bound
    • it consists of an outer cloud of protein called the centrosome matrix and an inner pair of centrioles 
  45. Inclusions
    • are temporary structures in the cytoplasm that may or may not be present in a given cell type
    • Ex. pigments, crystals of protein, and food stores (Lipid Droplets and Glycosomes)
  46. Lipid Droplets
    • are spherical drops of stored fat
    • look like lysosomes, but can be distinguished by their lack of a surrounding membrane
  47. Glycosomes 
    • "sugar-containing bodies"
    • store sugar in the form of glycogen, which is a long branching chain of glucose molecules, the cell's main energy source
  48. Nucleus
    • "little nut"
    • is the control center of the cell 
    • its genetic material, deoxyribonucleic acid (DNA), directs the cell's activities by providing the instructions for protein synthesis
  49. Nuclear Envelope
    the nucleus is surrounded by a nuclear envelope that consists of two parallel membranes separated by a fluid-filled space
  50. Nucleolus
    • there may be one or several within a cell nucleus
    • contains parts of several different chromosomes and serves as the cell's "ribosome-producing machine"
    • More Specific: it has hundreds of copies of the genes that code for ribosomal RNA and serves as the site where the large and small subunits of ribosomes are assembled
  51. The double helix composed of four kinds of subunits called nucleotides
    • Thymine (T)
    • Adenine (A)
    • Cytosine (C)
    • Guanine (G)
  52. How many chromosomes are there in a typical human cell?
    46 chromosome
  53. Cell Life Cycle
    is the series of changes a cell undergoes from the time it forms until it reproduces itself
  54. What is a gene?
    a sequence of DNA that gives rise to a protein or functional RNA
  55. Mitochondrial Theory
    • most free radicals are produced in the mitochondria, the organelle with the highest rate of metabolism
    • scientist propose that a decrease in energy production by free-radical damaged mitochondria weakens and ages the cells
  56. Genetic Theory of Aging
    • propose that aging is programmed into our genes
    • telomeres structures that limit the max number of times cells can divide (cap the ends of chromosomes)
    • Telomerase is an enzyme that prevents telomeres from degrading by adding more repeating DNA to the ends (occurs in germ-line cells and cancer cells)
  57. Karyotype
    a pictorial representation of chromosomes within a individual
  58. What is a genome?
    • is the complete set of an organism's genes
    • located mainly on chromosomes in the cell's nucleus
  59. Chromosome
    • is made of chromatin, a combo of DNA and protein molecules
    • are not visible in the cell until cell division
Card Set
Cells: The Living Units
Show Answers