LS7C: Week 1 Launchpad Questions and CQs

Which of the answer choices is a cellular response to signal transduction? A) a change in the proteins found in the cytosol B) a change in the activity of an enzyme C) the release of signaling molecules from the cell D) All of these choices are correct.

D) all of these choices are correct Signal transduction can produce many changes in the cell, ranging from changes in gene expression to the release of signals to communicate with other cells.

Notch and Delta are both transmembrane proteins involved in cell communication in the developing nervous system of vertebrate animals. What makes Notch different from Delta? Notch is a receptor, and Delta is a signaling molecule. Notch is a signaling molecule, and Delta is a receptor. Notch is required at higher density than Delta to alter cell fate. All of these choices are correct.

Notch is a receptor, and Delta is a signaling molecule. Delta binds to Notch on neighboring cells, activating Notch and causing signal transduction to prevent neuronal development in Notch-activated cells.

One example of a cellular response to a signal is the triggering of cell division. If a mutation occurred in the gene for the signal receptor in this pathway that caused the receptor to reject binding of the signal, what response can be predicted? The cell does not divide. The signal is not produced. The cell divides repeatedly without the signal.

The cell does not divide.

Which of the answer choices correctly lists the types of cellular communication from shortest to longest distance traveled by the signaling molecule to reach its responding cell? paracrine, autocrine, endocrine autocrine, paracrine, endocrine endocrine, paracrine, autocrine autocrine, endocrine, paracrine

autocrine, paracrine, endocrine (and even shorter is contact dependent )

Mammalian steroid hormones are signaling molecules that function in which type of cell signaling?

endocrine

Which signaling system involves the longest distance between release of a signaling molecule and activation of a receptor? autocrine endocrine paracrine contact-dependent

endocrine

T/F: A cell can only respond to signals from other cells, not from the physical environment

false

Kohler and Lipton first discovered platelet-derived growth factor (PDGF) by observing that fibroblasts: grew better in cell culture containing blood serum containing proteins released by platelets during clotting. grew at the same rate in cell culture containing either blood plasma or serum. grew better in cell culture blood plasma without the proteins released by platelets.

grew better in cell culture containing blood serum containing proteins released by platelets during clotting. Kohler and Lipton found that blood serum that was derived from clotted blood, in which platelets had released their contents to drive blood clotting, enhanced growth of fibroblasts better than blood plasma, in which platelets were still intact.

A receptor that is inside the cell would require a __________ signal molecule that can ____________________ the plasma membrane. nonpolar; pass through polar; pass through nonpolar; bind to polar; bind to

non polar; pass through

Growth factors such as platelet-derived growth factor (PDGF) function in: endocrine signaling.contact-dependent signaling.autocrine signaling.paracrine signaling.

paracrine signaling (short distance between two cells)

Signal molecules that are _______ usually have their corresponding receptor ______________ of the cell. nonpolar; on the surface polar;in the cytoplasm polar; on the surface

polar; on the surface

Which is the correct order for these steps in cell signaling? receptor activation, signal transduction, response response, signal transduction, termination receptor activation, response, signal transduction signal transduction, receptor activation, response

receptor activation, signal transduction, response

In many signaling pathways, once a signaling molecule binds to a receptor, the receptor becomes phosphorylated. This initial phosphorylation step best demonstrates: receptor activation. either cellular response or signal transduction .termination signal transduction cellular response.

receptor activation. When receptors bind to their signaling molecules, receptor activation results from a change in shape of the receptor that activates enzyme activity of the receptor or allows binding of other proteins to the receptor.

A _________ expresses a gene or genes that direct production of the signaling molecule, and the _______________ expresses a gene or genes that direct production of the _________________. signaling molecule; responding cell; signaling cell responding cell; receptor protein; signal protein responding cell; signaling cell; receptor protein signaling cell; responding cell; receptor protein

signaling cell; responding cell; receptor protein

When cells communicate by the signaling process, one cell produces a _________________ that must be received by the ___________ on or in the responding cell.

signaling molecule; signal receptor

The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on: the location of the tissue or organ with respect to the circulatory path. the presence of the appropriate receptors on the cells of the target tissue or organ. the membrane potential of the cells of the target organ. nothing; all hormones of the body are able to stimulate all cell types because hormones are powerful and nonspecific.

the presence of the appropriate receptors on the cells of the target tissue or organ. - Cellular response to any signaling requires that receptors are present that are activated by the signaling molecule.

Signaling molecules involved in paracrine and autocrine signaling: travel by diffusion. travel in the circulatory system. remain attached to the plasma membrane.

travel by diffusion. Paracrine signals are released by cells and diffuse to affect nearby cells, whereas autocrine signals are released by cells to diffuse and bind to receptors on that cell's own plasma membrane.

T/F: Signaling pathways have been conserved in a wide range of organisms

true why????what does this mean