Except for that portion of the insulin that combines with receptors in the target cells, the remainder is degraded by the enzyme _____?

TLS Online TPP Program

#Question id: 13122

#Unit 2. Cellular Organization

Choose the incorrect?

1- COPI vesicles transport proteins from the rough ER to the cis -Golgi; COPII vesicles transport proteins in the reverse s Direction.

2- The KDEL receptor binds more tightly to its ligand ar low pH, and it is thought that the receptor is able to bind KDEL peptides in the cis-Golgi but to release these peptides in the ER because the pH of the Golgi is slightly lower than that of the ER.

3- The KDEL sorting signal is recognized and bound by the KDEL receptor, a transmembrane protein found primarily on small transport vesicles shuttling between the ER and the cis -Golgi and on the cis-Golgi reticulum.

TLS Online TPP Program

#Question id: 13123

#Unit 2. Cellular Organization

Match the correct one?

A- COPI                           i- vesicles transport proteins from the ER to the Golgi.

B- COPII                          ii- vesicles mainly transport proteins in the retrograde direction between Golgi cisternae and from the cis -Golgi back to the ER.

C- Clathrin                      iii- vesicles transport proteins from the plasma membrane (cell  surface) and the trans-Golgi network to late endosomes.

TLS Online TPP Program

#Question id: 13154

#Unit 2. Cellular Organization

In starving cells, however, such degradation would deplete essential enzymes and regulatory proteins. Lysosomes therefore also have a selective pathway, which is activated only after a prolonged fast, that imports and degrades cytosolic proteins containing the pentapeptide  , the sequence is

TLS Online TPP Program

#Question id: 13155

#Unit 2. Cellular Organization

Lysozyme is an enzyme that destroys bacterial cell walls. It does so by hydrolyzing the β(1→4) glycosidic linkages from N- acetylmuramic acid (NAM or MurNAc) to N- acetylglucosamine (NAG or GlcNAc) in cell wall peptidoglycans. The only functional groups in the immediate vicinity of lysozyme’s reactive center that have the required catalytic properties are the side chains of Glu 35 and Asp 52.

a- Glu perform reaction in its protonated state and Asp perform reaction in its deprotonated state. 

b- Glu perform reaction in its deprotonated state and Asp perform reaction in its protonated state. 

c- both in its protonated form

d- both in its deprotonated form 

Choose the correct option?

TLS Online TPP Program

#Question id: 13156

#Unit 2. Cellular Organization

Tay sach;s disease are caused when which enzyme is mutated or non-functional?

TLS Online TPP Program

#Question id: 13157

#Unit 2. Cellular Organization

Following are the some statement . Choose the correct one?

a. Primary Lysosomes are also called storage granules, protolysosomes or virgin lysosomes. Primary lysosomes are newly formed organelles bounded by a single membrane and typically having a diameter of 100 nm. They contain the degradative enzymes which  participate in digestive process. 

b. Heterophagosomes are also called heterophagic vacuoles, heterolysosomes or phagolysosomes. Heterophagosomes are formed by the fusion of primary lysosomes with cytoplasmic vacuoles containing extracellular substances brought into the cell by any of a variety of endocytic processes.

c. Autophagosomes are able to digest intracellular structures including mitochondria, ribosomes, peroxisomes and glycogen granules.