Exam 7: Cell Communication and Multicellularity

The human pituitary gland secretes thyroid-stimulating hormone (TSH).TSH stimulates the thyroid gland to release thyroxine, a hormone that regulates metabolism.TSH has no effect on heart cells.Based on your knowledge of membrane receptors, what can you say about how cells in the thyroid gland compare with heart cells?

Refer to the table below. A student created the table to help her remember the differences between chemical signal types.Which statement about the table is true?

The rate of ion flow into or out of a cell is affected by the number of ion channels present in the cell membrane and by the concentrations of small molecules that open and close the channels.Consider that there are signal transduction pathways that stimulate expression of ion channel proteins to increase the number of ion channels in the membrane, and there are signal transduction pathways that stimulate production of small molecules that open or close channels.Which of these signal transduction mechanisms would be most effective for responses that need to change rapidly, and which would be most effective for responses that need to change slowly, and why?

Which statement about gap junctions is true?

Which experimental technique would be best used to investigate whether a transcription factor is activated as part of a signal transduction pathway?

A cell deep within a large multicellular organism receives its signals from

If a ligand binds to a G protein-coupled receptor but the normal exchange of GDP for GTP on the associated G protein does not take place, what will happen in the cell?

Increased synthesis of phosphodiesterase would most likely lead to

The binding of one molecule of epinephrine to a receptor can result in the activation of 1,000 molecules of glycogen phosphorylase.This is an example of signal _______.

Gap junctions allow passage of ions and small proteins from one cell to the next through small channels called

Refer to the figure below. The figure shows a signal transduction pathway in a cell.Which of the following plays a role in signal transduction in this case?

Which statement about cell signaling is false?

A signal transduction pathway was found to rely on a second messenger molecule that has no enzymes that change its chemical structure and no membrane pumps that remove it after it has completed its signaling function.The likely identity of this second messenger molecule is _______.

Refer to the table below, which summarizes effects of three hormones on different types of human cells. This information supports the concept that only cells with the appropriate _______ can respond to a chemical signal.

_______ is a second messenger found in the pathway in which epinephrine activates the liver enzyme that breaks down glycogen.

Refer to the figure showing the signal transduction pathway that is initiated by the binding of cortisol to its receptor. Based on the figure, cortisol acts as a signal and binds to its receptor, which is bound to a _______ protein.

Phosphorylation of a protein can lead to changes in its conformation, which can cause changes in its _______.

A cascade of events initiated by a signal that causes several different intracellular responses is an example of signal

Refer to the figure below. The figure illustrates how the signal in a signal transduction pathway can be _______.

Which statement about G proteins is true?