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Write true or false and please explain 30. In secretory cells, the constitutive

ID: 7227 • Letter: W

Question

Write true or false and please explain

30. In secretory cells, the constitutive and regulatory pathways of exocytosis diverge at the cis Golgi network. ------------------ ( ) ( )
31. Many proteins are posttranslationally glycosylated at tyrosine residues in the ER. ------------------------------------------------- ( ) ( )
32. Cells import LDL molecules exclusively through pinocytosis. ------------------------------------------------------------------------- ( ) ( )
33. Cells recycle LDL receptors from lysosome to the plasma membrane. ----------------------------------------------------------------- ( ) ( )
34. Phagosomes fuse with late endosome. ------------------------------------------------------------------------------------------------------ ( ) ( )
36. If a Sec mutant showed an accumulation of newly synthesized proteins at ER,
then the Sec gene is likely a component of vesicle-budding machinery of trans-Golgi network. ------------------------------------ ( ) ( )
37. A signal recognition particle is a single pass trans-membrane protein of the ER membrane. ---------------------------------------- ( ) ( )

Explanation / Answer

30. In secretory cells, the constitutive and regulatory pathways of exocytosis diverge at the cis Golgi network.

- false. Constitutive pathways works normally, where as regulatory pathway needs signals to function.

31. Many proteins are posttranslationally glycosylated at tyrosine residues in the ER.

- true. Liver and muscle glycogenin carries a glucose on a tyrosine side chain. This is the only known example of glycosylated tyrosine in nature.

32. Cells import LDL molecules exclusively through pinocytosis.

- it is receptor mediated endocytosis.

33. Cells recycle LDL receptors from lysosome to the plasma membrane.

-true.

34. Phagosomes fuse with late endosome.

- true.

37. A signal recognition particle is a single pass trans-membrane protein of the ER membrane.

- true.