Chapter 9: Cellular Communication

Hydrophobic ligands are.....

- Nonpolar - steroids - have direct effect on target cell as they diffuse into it

A scientist notices that a cancer cell line fails to die when he adds an inducer of apoptosis to his culture of cells. Which hypothesis could explain why the cells fail to die?

- The cells have a mutation that prevents the initiation of apoptosis signaling. - The cells have lost expression of the receptor for the apoptosis-inducing ligand. - The cells overexpress a growth factor pathway that inhibits apoptosis.

Apoptosis can occur in a cell when the cell is ________________.

- damaged - no longer needed - infected by a virus

Calcium is very essential in...

- muscle contraction and regulating heart beat and fluid balance within cells - building strong bones and teeth - blood clotting and nerve impulse transmission

Water soluable ligands are.....

- polar, require assistance into the cell - peptides, insulin and glucagon are examples

What is the function of a phosphatase?

A phosphatase removes the phosphate group from phosphorylated amino acid residues in a protein.

A scientist notices that when she adds a small, water-soluble molecule to a dish of cells, the cells turn off transcription of a gene. She hypothesizes that the ligand she added binds to a(n) ______ receptor.

Enzyme-linked

Cholera is an infections disease that causes extreme diarrhea, what cell to cell surface receptor and subsequent confirmation change is associated with this?

G-protein linked receptor and an ion channel

A doctor is researching new ways to treat biofilms on artificial joints. Which approach would best help prevent bacterial colonization of the medical implants?

Inhibit quorum sensing

Why are ion channels necessary to transport ions into or out of a cell?

Ions are charged particles and cannot diffuse through the hydrophobic interior of the membrane.

Paracrine signaling uses what types of cells to allow for fast signaling?

Nerve cells

How does PKC's signaling role change in response to growth factor signaling versus an immune response?

PKC interacts directly with signaling molecules in growth factor cascades, but interacts with signaling inhibitors during immune signaling.

Receptors are what type of macromolecule?

Protein

What is the effect of an inhibitor binding an enzyme?

The enzyme is inactivated.

What property prevents the ligands of cell-surface receptors from entering the cell?

The molecules bind to the extracellular domain.

What enzyme is used in phosphorylating Tyrosine?

Tyrosine Kinase

An ion channel is....

a channel through the membrane that allows a specific ion to pass through.

Quorum sensing is triggered to begin when ___________.

a sufficient number of bacteria are present

What is intercellular signaling?

cell to cell communication

What is Paracrine signaling?

communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior of those cells, and they move by diffusion through the extracellular matrix.

What is Direct signaling?

communication through water-filled channels allowing small signaling molecules, called intracellular mediators, to diffuse between the two cells.

What is Endocrine signaling?

communication travel from distant cells, many of which are located in endocrine glands such as the thyroid, hypothalamus and pituitary gland, and they have a slower response but a longer-lasting effect

What is intracellular signaling?

communication within the cell

The secretion of hormones by the pituitary gland is an example of _______________.

endocrine signaling

An Enzyme linked receptor is....

have intracellular domains that are associated with an enzyme; in some cases, the domain of the receptor is an enzyme.

Internal receptors are found in the cytoplasm of the cell and respond to...

hydrophobic (nonpolar) ligand molecules that are able to travel across the plasma membrane

In signal transduction, in which an extracellular signal is converted into a/an

intracellular signal

What is Autocrine signaling?

is a form of cell signaling in which a cell secretes a hormone or chemical messenger that binds to a receptors on that same cell, leading to changes in the cell

Endocrine signals are....

longer lasting and more gradual in terms of their effects

Which type of molecule acts as a signaling molecule in yeasts?

mating factor

An G-protein receptor is....

receptors bind a ligand and activate a membrane protein

Paracrine signals are....

short in duration, and immediate in their effect

What is a ligand?

signaling molecule

Second messengers are...

small molecules that propagate a signal after it has been initiated by the signaling molecule binding to the receptor.

Endocrine signals are transmitted more slowly than paracrine signals because ___________.

the ligands are transported through the bloodstream and travel greater distances

Internal receptors are found in the cytoplasm of the cell and once in the cell

these molecules bind to proteins that act as transcription regulators to mediate gene expression.