Cells ch3

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Author:
KellyM
ID:
197029
Filename:
Cells ch3
Updated:
2013-02-01 00:21:04
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parts cell structure function
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organelles to study
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  1. cytoplasmic organelles

    membranous
    nonmembranous
    • Membranous (surrounded by a cell membrane):
    • -mitochondria
    • -peroxisomes
    • -lysosomes
    • -endoplasmic reticulum
    • -golgi apparatus

    • Nonmembranous (not surrounded by membrane):
    • -cytoskeletan
    • -centrioles
    • - ribosomes
  2. mitochondria
    • rod-like, double-membrane structure w/shelflike cristae (invaginations)
    • provide most of cells ATP via aerobic cellular respiration
    • contain their own DNA and RNA
  3. Endoplasmic Reticulum (ER)
    • interconnected tubes and parallel membranes enclosing cisternae
    • continuous with nuclear membrane
    • 2 varieties: Rough ER, Smooth ER
  4. cytoplasm
    located b/w plasma membrane and nucleus

    -Cytosol: water w/solutes (protein, salts, sugars, etc)

    -Cytoplasmic organelles: metabolic machinery of a cell

    - Inclusions: granules of glycogen or pigments, lipid droplets, vacuoles, and crystals
  5. ribosomes
    • granules containing protein and rRNA (ribosomal RNA)
    • ***site of protein synthesis***
    • Free ribosomes synthesize soluble proteins
    • membrane-bound ribosomes, on rough ER, synthesize proteins to be incorporated into membranes or exported from teh cell
  6. Rough ER
    • external surface studded w/ribosomes
    • manufactures all secreted proteins
    • synthesizes membrane integral proteins and phopholipids
  7. Smooth ER
    tubules arranged in a looping network

    • enzyme (integral protein) functions:
    • 1) in the liver -- lipid and cholesterol metabolism, breakdown of glycogen, and, along with kidneys, detoxification of drugs, pesticides, and carcinogens
    • 2) synthesis of steroid-based hormones
    • 3) in intestinal cells - absorption, synthesis, and transport of fats
    • 4) in skeletal and cardiac muscle - storage and release of calcium
  8. golgi apparatus
    stacked and flattened membranes and associated vesicles close to the nucleus

    • modifies, concentrates, and packages proteins and lipids:
    • - transport vessels from ER fuse w/convex cis face of Golgi apparatus
    • - proteins then pass through golgi to trans face
    • - secretory vesicles leave trans face of golgi stack and move to designated parts of cell
  9. lysosomes
    • spherical membranous bags containing digestive enzymes such as acid hydrolases
    • digest ingested bacteria, viruses, and toxins
    • degrade nonfunctional organelles
    • break down and release glycogen
    • break down bone to release Ca2+
    • destroy cells in injured or non-useful tissue (autolysis)
    • "garbage cans of cells"
  10. endomembrane system
    • overall function =
    • produce, store, and export biological molecules
    • degrade potentially harmful substances
  11. peroxisomes
    • membraneous sacs containing powerful oxidases and catalases
    • detoxify harmful or toxic substances
    • neutralize dangerous free radicals (highly reactive chemicals w/unpaired electrons)
  12. cytoskeleton
    elaborate series of rods throughout cytosol

    -Microfilaments (actin subunits, spherical like pearls on a string, 7nm diameter)

    -intermediate filaments (fibrous protein, resembles a twisted cord, 10nm diameter)

    -Microtubules (tubulin subunits, resembles hollow tube, 25 nm diameter)
  13. centrosome
    • "cell center"
    • generates microtubules, organizes mitotic spindle
    • contains centrioles: small tubes formed by microtubules
  14. cellular extensions
    • cilia and flagella
    • -whiplike, motile extensions on surfaces of certain cells
    • - contain microtubules and motor molecules
    • - cilia move substances across cell surfaces
    • - longer flagella propel whole cells (tail of sperm)

    • Microvilli
    • -fingerlike extensions of plasma membrane
    • -increase surface area for absorption
    • -core of actin filaments for stiffening
  15. microtubules
    • cylindrical structures make of tubulin proteins
    • support the cell and give it shape
    • involved in intracellular and cellular movements
    • form centrioles and cilia and flagella, if present
  16. microfilaments
    • fine filaments composed of the protein actin
    • involved in muscle contraction and other types of intracellular movement
    • help form the cell's cytoskeletan
  17. intermediate filaments
    • protein fibers; composition varies
    • the stable cytoskeletan elements
    • resist mechanical forces acting on the cell
  18. centrioles
    • paired cylindrical bodies, each composed of 9 triplets of microtubules
    • organize a microtubule network during mitosis (cell division) to form the spindle and asters
    • form the bases of cilia and flagella
  19. cilia
    • short cell-surface projections; each cilium composed of 9 pairs of microtubules surrounding a central pair
    • coordinated movement creates a unidirectional current that propels substances across cell surfaces
  20. flagellum
    • like a cilium, but longer; only example in human is the sperm tail
    • propels the cell
  21. nucleus
    • largest organelle
    • surrounded by the nuclear envelope
    • contains fluid nucleoplasm, nucleoli, and chromatin
    • control center of cell
    • responsible for transmitting genetic info and providing instructions for protein synthesis
  22. plasma membrane
    • membrane made of a double layer of lipids (phospholipids, cholesterol, and so on) within which proteins are embedded
    • proteins may extend entirely through lipid bilayer or protrude on only one face
    • most externally facing proteins and some lipids have attached sugar groups
    • serves as external cell barrier and acts in transport of substances into or out of cell
    • maintains resting potential that is essential for functioning of excitable cells
    • externally facing proteins act as receptors (for hormones, neurotransmitters...), transport proteins, and in cell-to-cell recognition
  23. nuclear envelope
    • double-membrane structure pierced by pores
    • outer membrane continuos w/the endoplasmic reticulum
    • separates the nucleoplasm from the cytoplasm and regulates passage of substances to and from nucleus
  24. nucleolus
    dense spherical (non-membrane bounded) bodies, composed of ribosomal RNA and proteins
  25. chromatin
    • granular, threadlike material composed of DNA and histone proteins
    • DNA constitutes the genes
    • DNA (30%), histone proteins (60%), RNA (10%)
    • arranged in fundamental units called nucleosomes
    • condense into barlike bodies called chromosomes when the cell starts to divide

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