What is the reproductive difference between sea urchins and mammals 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: 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: 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: 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: 13121

#Unit 2. Cellular Organization

--------- act as a nuclear export factor and directs the associated mRNP to the central channel of the NPC by transiently interacting with FG- nucleoporins.

TLS Online TPP Program

#Question id: 13120

#Unit 2. Cellular Organization

Match the correct one?

Target organelle	Location of sequence within protein	Removal of sequence	Nature of sequence
1- ER	i- N- terminal	a- yes	P- Core of 6-12 hydrophobic aa often preceded by one or more basic ammo acids (Arg, Lys)
2-Mtochrondria matrix	ii- N- terminal	b- yes	Q- Multiple different kinds;  rich in Lys and Arg residues
3-Chloroplast stroma	iii- N- terminal	c- no	R- Lys and arg one side and other side hydrophobic aa
4-Nucleus	iv-varies	d- yes	S- Generally rich in ser and thr, poor in glu and asp