AP Bio Insta-Review Topic 4.1*: Cell Communication

What extracellular component aids in direct cell-cell communication?

• Cell Wall

• Cytoskeleton

• Glycolipid

• Secretory Vesicle

Answer explanation

Glycolipids are short carbohydrates attached to lipid molecules. These are used for cell to cell communication. The sugar component will bind to an active site on a receptor protein of another cell to communicate.

Signaling where ligand binds to nearby cell...?

• Autocrine

• Hormonal

• Paracrine

• Synaptic

Answer explanation

Paracrine signaling refers to a local signaling where the signaling molecule is released from a nearby cell then binds to a receptor on the target cell.

Signal that binds to the secreting cell...?

• Autocrine

• Hormone

• Paracrine

• Synaptic

Answer explanation

The prefix “auto” means self, so autocrine will bind to the same cell. The secreting cell is also the target cell. The signaling molecule is released from the cell then binds to a receptor on that same cell.

What type of signaling is shown?

• Autocrine

• Hormone

• Paracrine

• Synaptic

Answer explanation

In autocrine signaling, the secreting cell is also the target cell. As you see in the image, the cell secretes the signaling molecule then it binds to a receptor on the membrane.

Describe the pathway of signaling molecule released from the cell.

Answer explanation

› Protein synthesized in Rough ER

› Protein modified in Golgi bodies

› Secretory vesicle fuses with plasma membrane

› Signaling molecule released by exocytosis

Signaling by cell to cell contact like a Helper T cell binding to an antigen presenting cell. Which describes the type of signaling?

• Direct Signaling

• Local Signaling

• Long Distance Signaling

• Synaptic Signaling

Answer explanation

The antigen presenting cell has the antigen bound to a MHC on the membrane. The white blood cell receptor will bind to the antigen. This is a direct contact between the two cells hence “direct signaling”.

In autocrine signaling, which cell released the signal?

• A nearby cell

• An endocrine cell

• The brain cell

• The same cell

Answer explanation

In autocrine signaling, the secreting cell is also the target cell. The prefix “auto” means self so the signaling molecule will be released then bound to the same cell.

In endocrine signaling, what cell released the signal?​

• A nearby cell

• An endocrine cell​

• The brain cell​

• The same cell​

Answer explanation

Endocrine signaling is a long distance signaling. An endocrine cell will release the signaling molecule into the blood stream which will carry the signaling molecule to the target cell.

In paracrine signaling, which cell released the signal?​

• A nearby cell​

• An endocrine cell​

• The brain cell​

• The same cell​

Answer explanation

Paracrine signaling refers to a local signaling where the signaling molecule is released from a nearby cell then binds to a receptor on the target cell.

Where is the receptor for a steroid hormone?​

• Intracellular​

• Membrane Bound​

Answer explanation

Steroids are nonpolar due to their carbon ring structures. The plasma membrane is also nonpolar. The steroid is able to pass directly through the membrane so the receptor needs to be on the inside of the cell (intracellular)