AP Bio Cell Signaling Quiz #1

Which of the following is true for the signaling system in an animal cell that lacks the ability to produce GTP?

• It could activate only the epinephrine system.
• It would be able to carry out reception and transduction but would not be able to respond to a signal.
• It would not be able to activate the G protein on the cytoplasmic side of the plasma membrane.

• It would employ a transduction pathway directly from an external messenger.

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

• Estrogen is produced in very large concentration and therefore diffuses widely.
• Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding.
• The subcomponents of estrogen, when metabolized, can influence cell response.
• Estrogen is kept away from the surface of any cells not able to bind it at the surface.

Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because

• they amplify the original signal manyfold.
• they always lead to the same cellular response.
• they are species specific.
• the number of molecules used is small and fixed.

In cell signaling, how is the flow of specific ions

regulated?

• Opening and closing of ligand-gated channels

• Transduction

• Cytoskeleton rearrangement

• Endocytosis

Many signal transduction pathways use second messengers to:

• transport a signal through the lipid bilayer portion of the plasma membrane.

• relay a signal from the outside to the inside of the cell.

• relay the message from the inside of the membrane throughout the cytoplasm.

• amplify the message by phosphorylating proteins.

Which of the following can activate a protein by transferring a phosphate group to it?

• cAMP

• G proteins

• phosphodiesterase

• protein kinase

A signal molecule that binds to a plasma-membrane protein is a

• ligand
• second messenger
• protein kinase
• receptor protein

What determines whether a cell is a target cell for a particular signal molecule (ligand)?

• phosphorylation cascade
• cAMP
• The shape of its signal receptors

• phosphatase

Which of the following is a chemical message that usually travels through the bloodstream to target cells?

• hormone
• local regulator
• endocrine cell

The 3 steps of signal transduction in order are

• reception, transduction, response
• response, transduction, reception
• reception, response, transduction
• transduction, reception, response