Biology

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spagem84
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99403
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Biology
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2011-09-13 12:09:09
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Chapter 4
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  1. Be familiar with the early history of the microscope and cells (names of scientists and their contributions).
    The first microscopes were light microscopes

    • In 1665 Robert Hooke used a crude microscope to examine a piece of cork
    • o He compared the structures he saw to “little rooms” cellulae in Latin therefore the name cells stuck

    ANtoni van Leeuwen hoek, worked with more refined lenses, examined numerous subjects, from blood and sperm to pond water. His reports included drawings and enthusiastic descriptions of discoveries
  2. Describe the differences between light microscopes and electron microscopes (SEM and TEM) and what these microscopes are able to reveal to the human eye.
  3. Light microscopes: visible light is passed through a specimen and the through glass lenses. The lenses bend the light in such a way that the image of the specimen is magnified. It can reveal a microorganism, or a then slice of animal or plant tissue
  4. Electron microscope: focuses a beam of electrons through a specimen or onto its surface. It can distinguish structures as small as 2 nanometers (nm) and is high resolution has enabled biologists to explore cell ultrastructure, the complex internal anatomy of a cell
  5. Scanning electron microscope (SEM): uses an electron beam to scan the surface of a cell which is usually coated with a thin film of gold. used to study the detailed architecture of cell surfaces.
    Transmission microscope (TEM): aims an electron beam through a very thin section of a specimen, just as a light microscope aims a beam of light through a specimen. It uses electromagnets as lenses to bends the paths of the electrons, magnifying and focusing an image onto a viewing screen or photographic film. It is used to study the details of internal cell structure
  6. List the statements of cell theory.
    The theory that all living things are composed of cells and that all cells come from other cells. Discovered in the mid 1800’s
  7. Describe how cell volume and surface area set limits to cell size.
    Large cells have more surface area than small cells, but they have much less surface area relative to their volume than small cells. Volume= (height) x (width) x (length) where surface area= 6 x (height x width)




    Total volume

    27 units cubed

    27 units cubed


    Total surface area

    54 units squared

    162 units squared


    Surface-to-volume ratio

    2

    6
  8. Know the function of the plasma membrane of a cell.
    It forms a flexible boundary between the living cell and its surroundings
  9. Describe the structure of the “phospholipid bilayer” membrane found in all cells.
    Composed of two distinct regions-a head with a negatively charged phosphate group and two non-polar fatty acid tails
  10. Differentiate between prokaryotic (Bacteria and Archaea) and eukaryotic cells (Eukarya).
    • Prokaryotic cells lack a membrane-enclosed nucleus and other membrane-enclosed organelles.
    • They evolved before eukaryotic cells

    Eukaryotic cells are distinguished by having a membrane-enclosed nucleus, which houses most of their DNA.

    • Similarities:
    • Have one or more chromosomes, contain ribosomes, interiors have a cytoplasm
    • However in eukaryotic cells refers only to the region between the nucleus and the plasma membrane
  11. Define chromosomes, plasma membrane, cytoplasm, ribosomes, and organelles.
    • Chromosomes: a threadlike, gen-carrying structure found in the nucleus of a eukaryotic cell
    • most visible during mitosis and meiosis

    plasma membrane: the membrane at the boundary of every cell that acts as a selective barrier

    cytoplasm: the contents of a eukaryotic cell between the plasma membrane and the nucleus

    ribosomes: a cell structure consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in the cytoplasm

    organelles: a membrane-enclosed structure with a specialized function within a cell
  12. List the structures found in all cells.
    • Structures found in all cells (animal and plant):
    • Nucleus
    • Nuclear envelope, chromatin, nucleolus
    • Rough endoplasmic reticulum
    • Smooth endoplasmic reticulum
    • Ribosomes
    • Golgi apparatus
    • Mitochondrion
    • Peroxisome
    • Plasma membrane
    • Cytoskeleton
    • Microtubule
    • Intermediate filament
    • Microfilament

    • Structures only found in prokaryotic cells (plant):
    • Central vacuole
    • Chloroplast
    • Cell wall
    • Plasmodesma

    • Structures only found in eukaryotic cells (animal):
    • Lysosomes
    • o Centrioles
  13. Define and describe the functions of the following structures: nucleus
    1.An atom’s central core, containing protons and neutrons 2. The genetic control center of a eukaryotic cell
  14. Define and describe the functions of the following structures: chromatin
    The combination of DNA and proteins that constitutes eukaryotic cells
  15. Define and describe the functions of the following structures: nuclear envelope
    A double membrane that encloses the nucleus perforated with pores that regulate traffic with the cytoplasm
  16. Define and describe the functions of the following structures: nucleolus
    A structure within the nucleus where ribosomal RNA is made and assembled with proteins imported from the cytoplasm to make ribosomal subunits
  17. Define and describe the functions of the following structures: endomembrane
    A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles
  18. Define and describe the functions of the following structures: vesicles
    A sac made of membrane in the cytoplasm of a eukaryotic cell
  19. Define and describe the functions of the following structures: endoplasmic reticulum (smooth and rough),
    • EDR (ROUGH)
    • the portion of ER with ribosomes attached that make membrane proteins and secretory proteins


    • EDR (SMOOTH)
    • The portion of ER that lacks ribosomes
  20. Define and describe the functions of the following structures: ribosomes
    A cell structure consisting of RNA and protein organized into two subunits and functioning as the site protein synthesis in the cytoplasm. In eukaryotic cells, the ribosomal subunits are constructed in the nucleolus.
  21. Define and describe the functions of the following structures: Golgi apparatus
    An organelle in eukaryotic cells consisting of stacks of membranous sacs that modify, store, and ship products of the ER
  22. Define and describe the functions of the following structures: lysosome
    A digestive organelle in the eukaryotic cells; contains hydrolytic enzymes that digest engulfed food or damaged organelles.
  23. Define and describe the functions of the following structures: vacuoles
    A membrane-enclosed sac that is part of the endomembrane system of a eukaryotic cell and has diverse functions
  24. Define and describe the functions of the following structures: peroxisome
    An organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen, producing and then degrading hydrogen peroxide
  25. Define and describe the functions of the following structures: mitochondria
    An organelle in e.c. where cellular respiration occurs, enclosed by two membranes, it is where most of the cell’s ATP is made
  26. Define and describe the functions of the following structures: chloroplast
    An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive synthesis of organic molecules (sugars) from carbon dioxide and water
  27. Define and describe the functions of the following structures: endosymbiosis
    Refers to a cell that lives within another cell, called the host cell
  28. Define and describe the functions of the following structures: plasmodesmata
    An open channel in a plant cell wall through which strands of cytoplasm connect from adjacent cells
  29. Define and describe the functions of the following structures: plasma membrane
    The membrane at the boundary of every cell that acts as a selective barrier to the passage of ions and molecules into and out of the cell; consists of phospholipids bilayer with embedded proteins
  30. Define and describe the functions of the following structures: cell wall
    • A protective layer external to the plasma membrane in prokaryotic cells
    • in plants, fungi, and some protists
  31. Define and describe the functions of the following structures: central vacuole
    In a plant cell, a large membranous sac with diverse roles in growth and the storage of chemicals and waste
  32. Define and describe the functions of the following structures: cytoskeleton
    • A network of protein fibers in the cytoplasm of a eukaryotic cell
    • Includes microfilaments, intermediate filaments, and microtubules
  33. Define and describe the functions of the following structures: microfilaments
    The thinnest of the three main kinds of protein fibers making up the cytoskeleton of a eukaryotic cell;
  34. Define and describe the functions of the following structures: microtubules
    The thickest of the three main kinds of fibers making up the cytoskeleton of a e.c
  35. Define and describe the functions of the following structures: cilia
    A short cellular appendage specialized for locomotion
  36. Define and describe the functions of the following structures: flagella (both cilia and flagella are made of the same arrangements of microtubules)
    A long cellular appendage specialized for locomotion
  37. Define and describe the functions of the following structures: extracellular matrix (in animals)
    The meshwork surrounding animal cells; consists of glycoproteins and polysaccharides
  38. Define and describe the functions of the following structures: cell junctions (in animal tissues)
    Animal tissues often adhere, interact and communicate through junctions
  39. Tight junctions
    • The plasma membranes of neighboring cells are tightly pressed against each other and knit together by proteins
    • Anchoring junctions
    • Function like rivets, fastening cells together into strong sheets
    • Gap junctions
    • Also called communicating junctions
    • Are channels that allow small molecules to flow through protein-lined pores between cells
  40. Define and describe the functions of the following structures: cell walls (in plants, fungi, and some protists).
  41. Group eukaryotic cell structures with their appropriate functions (Table 4.22).

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