Flashcards in Biochem - Cellular (Cytoskeleton, Plasma membrane, & their elements) Deck (33):
What is the structure of a microtubule, and what are its components?
Cylindrical structure composed of a helical array of polymerized heterodimers of alpha- and beta-tubulin. Each dimer has 2 GTP bound
What are 3 cellular structures into which microtubules are incorporated?
Incorporated into flagella, cilia, mitotic spindles.
Briefly describe the growth and collapse of microtubules.
Grows slowly, collapses quickly
What function do microtubules serve in neurons?
Also involved in slow axoplasmic transport in neurons
Draw a microtuble, including and labeling the following: (1) Positive end (2) Protofilament (3) Negative end (4) Heterodimer.
See p. 78 in First Aid 2014 for visual at top left corner
What is the function of Molecular motor proteins?
Molecular motor proteins - transport cellular cargo toward opposite ends of microtubule tracks
What are 2 examples of Molecular motor proteins? What is the function of each?
(1) Dynein = retrograde to microtubule (+ => -) (2) Kinesin = anterograde to microtuble (- => +)
Name 5 drugs that act on microtubules. Give the major clinical use or class of each.
Drugs that act on microtubules: (1) Mebendazole (anti-helminthic) (2) Griseofulvin (anti-fungal) (3) Colchicine (anti-gout) (4) Vincristine/Vinblastine (anti-cancer) (5) Paclitaxel (anti-cancer); Think: "Microtubules Get Constructed Very Poorly"
What is the structure of cilia?
9 + 2 arrangement of microtubules
What is Axonemal dynein, and what function does it serve?
Axonemal dynein - ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
What is another name for Kartagener syndrome? What is the defect, and what immediate effect does it have?
Kartagener syndrome (primary ciliary dyskniesia) - immotile cilia due to a dynein arm defect
What symptoms are associated with Kartagener syndrome in males versus females, and why?
Results in male and female infertility due to immotile sperm and dysfunctional fallopian tube cilia, respectively
For what condition does Kartagener syndrome increase the risk in women?
Increased risk of ectopic pregnancy
What are 3 conditions that can be caused by Kartagener syndrome?
Can cause bronchiectasis, recurrent sinusitis, and situs inversus (e.g., dextrocardia on CXR)
Name 3 different kinds/categories of cytoskeletal elements.
(1) Actin and myosin (2) Microtubule (3) Intermediate filament
What are 4 processes/structures in which actin and myosin function?
Muscle contraction, Microvilli, Cytokinesis, Adherens junction
Compare/Contrast actin and myosin, particularly in terms of their structure.
Actins are long, structural polymers. Myosins are dimeric, ATP-driven motor proteins that move along actins
In one word, what is the major purpose of the microtubule?
What are 5 structures/processes in which microtubules function?
Cilia, Flagella, Mitotic spindle, Axonal trafficking, Centrioles
In one word, what is the major purpose of intermediate filaments?
What are 6 examples of intermediate filaments?
(1) Vimentin (2) Desmin (3) Cytokeratin (4) Lamins (5) Glial fibrillary protein (GFAP) (6) Neurofilaments
Describe the structure of the plasma membrane.
Asymmetric lipid bilayer
What are 5 substances contained in the plasma membrane?
Contains cholesterol, phospholipids, sphingolipids, glycolipids, and proteins
What substance do fungal membranes contain?
Fungal membranes contain ergosterol
What cell type is identified using an immunohistochemical stain for Vimentin?
What cell type is identified using an immunohistochemical stain for Desmin?
Muscle; Think: "desMin = Muscle"
What cell type is identified using an immunohistochemical stain for Cytokeratin?
What cell type is identified using an immunohistochemical stain for GFAP?
Neuroglia; Think: "Gfap = neuroGlia"
What cell type is identified using an immunohistochemical stain for Neurofilaments?
Where is the Na+-K+ ATPase located, and on which side is its ATP?
Na+-K+ ATPase is located in the plasma membrane with ATP site on the cytosolic side.
What happens to Na+ and K+ for each ATP consumed by the Na+-K+ ATPase?
For each ATP consumed, 3 Na+ go out and 2 K+ come in
What is the function of Ouabain?
Ouabain inhibits (sodium-potassium pump) by binding to K+ site