Exam 9: Cell Communication

A mutation in the DNA binding domain of a steroid hormone receptor is most likely to affect the

In plants,cell-cell junctions can only occur at gaps in the cell walls through cytoplasmic connections that form across the plasma membranes of the touching cells.These junctions are called

Synaptic signaling requires which of the following to be released into the synaptic gap?

Chemically-gated ion channels are receptor proteins through which ions pass.A cell biologist has blocked these channels in a lab rat's liver tissue by using a chemical that

Hormones are an example of intercellular communication known as _____________ signaling.

A mutation that affects Ca⁺⁺ binding to calmodulin is most likely to interfere with which aspect of a signal transduction pathway?

Signals with short-lived,local effects are called

In the digestive tract adjacent cells develop connections to form a sheet that prevents leakage of small molecules.These connections between cells are called

All of the following statements about chemically-gated ion channels are true except

A researcher is investigating several MHC proteins.That means she is

Tight and anchoring _______ cause cells to adhere tightly to each other.

The protein SOS is a guanine nucleotide exchange factor for Ras.SOS helps facilitate the exchange of GDP for GTP.What would be the effect of a mutation that inhibits the interaction between SOS and Ras?

Communication between cells can occur by all of the following basic mechanisms except

The molecules that convert extracellular signals into intracellular ones are

Leptin is a hormone that is produced by fat cells and plays a role in body metabolism and obesity.Studies have demonstrated that when obese mice are injected with leptin they quickly lose their excess weight.Interestingly,however,many overweight people have high levels of leptin in their bloodstream.Which of the following explanations is most consistent with this observation?

Short-lived,causing local effects.

The protein Sonic Hedgehog (SHH)plays a role in specifying the identity of digits (such as fingers,etc. )in mammals.Several digits arise directly from cells that both express and respond to secreted SHH.In this case,SHH is acting as

A biochemist is designing a new drug that will mimic the shape and function of a particular signal molecule.Therefore she must produce a molecule that will bind to the receptor protein and

Which of the following is not part of the cell communication system in animal cells?

Chemically-gated ion ________ open or close when signal molecules bind to the channel,allowing specific ions to diffuse through the channel.