Question

answer only question number 7.please answer only question number 7

Why termination of a cell signaling event is important? Explain with two examples how GPCR signaling is terminated. What is actin filaments treadmilling? What would be the consequence for actin filament assembly/disassembly if a mutation prevented actin's ability to bind ATP? What would be the consequence if a mutation prevented actin's ability to hydrolyze ATP? Predict the effect on a cell's actin cytoskeleton if function blocking antibody against cofilin was microinjected into cells. How can you prepare one very stable actin filament in-vitro: artificially? How cellular components have bidirectional movement on microtubules? Is it possible for certain cellular components to move on both directions along actin filament? What is MTOC? How it play important role during cell division? Kinesin has two globular domains and each can bind to beta-tubulin. Alpha & beta-tubulin dimer has length 8-nm. What is the length of the steps for kinesin? Is this a continuous speed or does kinesin take discrete steps? How does the interaction of myosin and actin affected by ATP binding? What will the effect of a non-hydrolyzable analogue of ATP on muscle contraction? And why? What is stem cell self renewal? How self renewal is regulated? What is neurotrophin, explain with example? What are the possible fates of a cell after injury? What are the effect of mitogen in stem cell self renewal? What are caspases? What is the mechanism of caspases activation? How caspases activation leads to apoptosis? Describe the function of oncogene and tumor-suppressor gene with example?

Answer 1

Stem cell self renewal is the capability of the cell to undergo several cycles of cell division while maintaining the undifferentiated state. The self renewal programs are regulated by cell-extrinsic signals from the niche, the microenvironment that maintains stem cells and regulates their function in tissues.

Neurotrophins are a family of proteins that induce the survival, development, and function of neurons. They belong to a class of growth factors, secreted proteins that are capable of signaling particular cells to survive, differentiate, or grow. Example neurotrophin-3 is a protein growth factor that helps to support the survival and differentiation of existing neurons and encourages the growth and differentiation of new neurons and synapses.

Possible fates of a cell after injury are necrosis , apoptosis or repair,regeneration and replacement.

Mitogen helps in regulating development and in forming differentiated cells.