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28 Cards in this Set
- Front
- Back
what are the three proteins involved in cell adhesion
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2) 80 kDa protein 3) discoidin |
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what is CAD-1
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expressed during cell adhesion - aggregation of ameoba -cell surface protein -a type of glycoprotein -involved in cells sticking together -not a strong interaction since is a one small, protein |
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what is the 80kDa adhesion protein
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-a complex of proteins called site A similar to mammalian protein - CAM -CAM - cell adhesion molecule -form a tight aggregate -cAMP turns on its expression |
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order of proteins expressed in the aggregation of ameoba in the slime mold
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2) then when camp binds - CSA gene/CAM is expressed = tighter aggregate 3)discoidin - start of culmination |
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what is discoidin
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the last adhesion protein expressed in distychstelium allow the multicell organism to adhere to outsite environment starts to express during culimination (after aggregation) |
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what is culmination
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making the fruiting body |
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what is discoidin's mammal homologue?
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integrin is used in mammals to attach cells to extracell substances/matrix |
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what is CF factor
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called the counting factor determines how many cells can adhere, detects aggregate up to 10,000 cells inhibits adhesion after this number |
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why limit the number of cells in an aggregate?
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don't want to get to large, hard to maintain, move together |
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adhesion proteins initiate signal transduction inside the cells
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initiate cell stage, specific response |
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once aggregation finishes what occurs
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moves as a multicell organism |
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what is culmination
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cells differentiate form fruiting body |
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what are the conditions that initiate culmination and why
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-ammonia is byproduct of protein metabolism - shows that bacteria are around and being digested by other ameoba -high ammonia concentration = bacteria present -low ammonia = not a lot of bacteria present = favors culmination |
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what is the mechanism behind ammonia concentrations - leading to culmination
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ammonia interferes with camp signaling - won't continue culmination process, can even dissociate |
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how does control of DNA lead to differentiation?
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leads to differentiation, gives cell its character and function |
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how does the slug determine which part differentiates into what (spore or stalk)
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-posterior end - end of the slug location of the cells in the slug = determine what it differentiates into location seems random |
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which part of the slug differentiates into what (spore or stalk)
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-posterior portion of slug become prespore -tip of posterior - ALC - anterior like cells are located, part of stalk formation |
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receptors and signals involved in differentiation |
high concentrations are present in the slug since cells are close together |
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where are CAR-3 and 4 expressed |
CAR-3 is expressed in the anterior portion of slug |
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pathway when CAR-4 binds to camp?
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CAR-4 when binds to camp - activates phosphotyrosine phosphatase - which removes phosphate group from GSKA -GSKA deactivated - promote spore gene expression |
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when CAR-3 binds to camp?
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activate ZAK-1 a kinase - phosphorylates GSKA phosphorylated GSKA promotes stalk gene expression |
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GSKA
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phosphorylated when CAR-3 active, ZAK-1 active, stalk expression dephosphorylated when CAR-4 active, spore expression |
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what does GSKA's homologue do in mammals
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also determines cell fate |
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how are stalk cells further differentiated after GSKA, what are the different stalk cell types |
-PSTO - upper cup of stalk -PSTA - actual stalk long portion -PSTAB - lower cup of stalk -anterior like cells on the posterior end of the slug - make the basal disk of stalk prespore cells sit on the basal disk |
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pathway of Dif-1
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signal passes to STAT - signal transduce and activator of transcription -in dictastelium, STAT actually inhibits transcription |
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what does Dif-1 STAT do when activated
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Dif-1 migrates within slug to create differentiation amongst cells |
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what happens after the stalk cells are differentiated
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-once stalk is formed, spore cells are pushed to the cup at the top of the stalk -spores in the cup can be spread and released into atmosphere, they are heat and cold reistant, can survive bad conditions |
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can the cells undifferentiate
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no, once ammonia level is too low and camp has bound to receptors, can't go back to being single cells |