Exam 9: Cellular Signaling

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogen and other steroid hormones. How can one hormone, such as estrogen, mediate so many different effects?

An inhibitor of which of the following enzymes could be used to block the release of calcium from the endoplasmic reticulum?

If an animal cell suddenly loses the ability to produce GTP, what will most likely happen to its signaling system?

A drug could inhibit the release of glucose from liver cells by having which of the following effects on the liver cells?

A protein kinase is an enzyme that functions in which of the following ways?

What does it mean to say that a signal is transduced?

A type of localized signaling in which a cell secretes a signal molecule that affects neighboring cells is best described as which of the following?

Consider the following pathway: Epinephrine → G protein-coupled receptor → G protein → adenylyl cyclase → cAMP Which of the following molecules serves as the second messenger in this pathway?

Binding of a growth factor to its receptor is most likely to immediately activate which of the following molecules?

Certain receptor tyrosine kinases (RTKs) that promote excessive cell division are found at high levels in various cancer cells. HER2 is an RTK that is present at excessively high levels in some breast cancer cells. Herceptin is a protein that binds to HER2 and inhibits cell division. Herceptin may be an effective treatment for breast cancer treatment under which of the following conditions?

Which of the following occurs during apoptosis?

Which of the following statements best explains why testosterone, a lipid-soluble signaling molecule that crosses the membranes of all cells, affects only target cells?

Protein phosphorylation is commonly involved with which of the following?

Which of the following statements best describes why phosphorylation cascades are useful in cellular signal transduction?

Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of substances on opposite sides of the membrane?

Which of the sequences below best describes the sequential steps (numbered 1-5) in a signal transduction pathway that utilizes a G protein-coupled receptor? 1) The signal-receptor complex activates a G protein. 2) Protein kinases are activated. 3) A signal molecule binds to a receptor. 4) Target proteins are phosphorylated. 5) cAMP is produced.

Which of the following activities would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins?

Which of the following statements best describes how steroid hormones access their receptors within target cells?

Which of the following statements describes a likely effect of a drug that inhibits testosterone binding to its receptor in human cells?

What is a primary function of transcription factors?