PRIN 4 Organization of the Cell Flashcards
diastrase
enzyme that digests glycogen
*was used to clear the liver biopsy sample of glycogen. As a result, PAS allows visualization of the glycosylated granules of alpha1-proteinase inhibitor that was defective and trapped in the rER
Plasma vs Serum
PLASMA: contains all clotting factors
SERUM: after clotting factors have been removed
What is “Alpha-1 antitrypsin?”
- protein that is produced mostly in the liver
* protects the lungs from neutrophil elastase
What is “Neutrophil elastase?”
- enzyme that digests damaged or aging cells and bacteria in the lungs
- regulated by alpha 1 proteinase inhibitor
What is the result of alpha1-proteinase inhibitor def?
Elastase digests lung tissue in an uncontrolled fashion and leads to emphysema
***HIGH risk of lung disease
How is Kartageners Syndrome inherited?
Autosomal recessive mutation
What causes Kartageners Syndrome?
loss of dynein arms: cilia don’t work properly
Clinical Manifestation of Kartageners Syndrome:
(1) recurrent upper resp infections
(2) male infertility
(3) ectopic preg
(4) organs on wrong side
What causes CF?
Cystic Fibrosus Autosomal recessive (CFTR gene) *Defect in ABC transporter (ATP-binding cassette) results in faulty transmembrane protein that is an epithelial Cl- channel
What happens to the faulty CFTR gene in CF?
gets degraded by proteosome
Newly made proteins leave the rER and go where?
cis face of golgi via vesicle with COP2 coat
How do vesicles get BACK to the golgi?
via COP1 coat
What is the “H-antigen?”
*protein that is expressed on RBC membrane surfaces
What is glyco-syl-transferase?
- protein that modifies H-antigen on RBC surfaces
* exists in 3 forms depending on the 3 allele forms: ABO
What does the O allele result in?
encodes for an inactive glyco-syl-transferase leaving the H antigen unmodified
Example of Regulated Secretion
(1) Synaptic Transmission
(2) Mast Cell
(3) Salivary Glands
How is exocytosis regulated in Synaptic Transmission?
V-SNARE on vesicle interacts with T-SNARE on target
How do tetanus toxins disrupt synaptic transmission?
cleave SNARES preventing interaction and release of contents into synaptic cleft
How does hay fever result in allergies?
Hay fever toxins mimic IgE and bind & stimulate release of Mast Cell granules
What causes scurvy?
Lack of Vit C
Vit C is involved in recycling of enzyme proline hydroxylane which is needed to make collagen in rER
Proteosome vs Lysozome
PROTEOSOME: recycling of intracellular cytoplasmic materials
LYSOSOME: digestion of endocytized material
Orientation of Hepatocyte
BASAL: Sinusoids (Hepatic Artery branch & Portal Vein branch)
APICAL: Secrete bile into Bile Canaliculi which flows into Bile Duct
Cytoskeleton Sizes
Microfil: 5-9nm
Int. Fil: 10-12nm
Microtub: 25nm
Name for Intermediate Filaments in epithelia
Keratins
Name for Intermediate Filaments in Muscle
Desmin
Name for Intermediate Filaments in CT
Vimentin
Name for Intermediate Filaments in neurons
Neurofilaments
What are the roles of Microtubules?
(1) moving cargo around cell
(2) cilia (bronchials, sperm)
(3) spindle formation
Cell-Cell Attachments
(1) ZONULA ADHERINS (cadherins, catenin, actin)
(2) ZONULA OCCLUDENS (tight junctions)
(3) DESMOSOMES (macula densa)
(4) GAP JUNCTIONS (via connexons)
How to recognize Microtubules on EM?
They are HOLLOW
What does “Zonula Adherens” mean?
Zonula = Belt
cadherins, catenin, actin
Descibe the Core Junction Complex in cells
Receptors: cadherins
Linkers: Catenins
Cytoskeleton: Actin
Why are Cadherins so important for development?
Each tissue has specific cadherins so that they stick to only those of similar kind
What do Catenins do?
(1) LINK cadherins to actin cytoskeleton
(2) signal transduction
Where are desmosomes located?
usually more basal than Zolulas but can be located anywhere along lateral surface
How are desmomes linked?
linked to stable intermediate filaments
**provide tensile strength
Structure of Gap Junctions
Connexins = pores
Cell-ECM Attachments
HEMIDESMOSOMES (stable)
FOCAL ADHESIONS (dynamic)
What do Hemidesmosomes anchor to?
Basal Lamina
What do Focal Adhesions do?
Example?
- migrate according to kinase activity
* Movement of neurons to extend their dendrites to form new synapses
What is the role of APC?
APC (tumor supp.) roams the cell and sends loose B-catenin to the Proteosome.
(Wnt turns of APC)
What gives microvili their shape?
Actin
Invagination vs Evagination
Invagination: infolding of one part within another part of a structure
Evagination: obtrusion of a layer or part to form a pouch.
Why can’t a protein that is normally synthesized on the rough ER be translated in the cytosol and THEN enter the ER lumen?
Proteins must cross into the ER as they are being synthesized
Hyperplasia vs Hypertrophy
Hyperplasia = increase in number of cells Hypertrophy = increase in size of cells
Hemidesmosomes VS Focal Adhesions
Hemidesmosomes = static
Focal Adh = dynamic
What can cause tissue enlargement?
(1) Hyperplasia
(2) Hypertrophy
(3) Increase in ECM
(4) Increased Perfusion
(5) Inflammation
(6) Inc spaces between cells
(7) Scarring/fibrosis
Why does repeated elastase activity reduce the total amount of lung elastin over time?
elastin synthesis essentially ceases after the age of about 18 years
Variants of a1 anti-trypsin
MM - normal pop
MZ - hetero (Lucy’s parents)
ZZ - Lucy
Where does Protein synthesis of lysosomal enzymes occur?
rER
What is the function of Clathrin-coated vesicles?
Transport from trans face of the Golgi apparatus to lysosomes and from the PM into the cell.
How and where are Lysosomal enzymes produced?
Lysosomal enzymes are synthesized in rough ER and are targeted through the Golgi before ending up in lysosomes.
True or False:
Alpha-1-antitrypsin is a neutrophil enzyme that degrades elastin in the lungs
FALSE … here’s the truth:
Alpha-1-antitrypsin: proteinase inhibitor
Elastase: neutrophil enzyme
