Chemical Messengers and Communication

Dr. Ketchum discusses chemical messengers, focusing on intercellular communication. The lecture covers the classification of chemical messengers into functional and chemical categories, explaining how they are synthesized, transported, and how they interact with target cells. The differences between direct and indirect communication are highlighted, with an emphasis on the role of gap junctions in direct communication. The lecture concludes with a review of the chemical properties of messengers and their impact on cellular communication.

Why is intercellular communication crucial for survival?

• It prevents cells from dying.

• It helps cells to grow larger.

• It enables cells to communicate and coordinate functions.

• It allows cells to divide.

What is a chemical messenger also known as?

• A neurotransmitter

• A receptor

• A ligand

• A hormone

What is the function of a secretory cell in intercellular communication?

• To synthesize and secrete ligands

• To receive ligands

• To destroy ligands

• To transport ligands

Which of the following is NOT a functional classification of chemical messengers?

• Paracrine signaller

• Eicosanoid

• Neurotransmitter

• Hormone

Which chemical property describes a lipophilic ligand?

• Non-polar

• Hydrophilic

• Polar

• Hydrophobic

Which of the following is a chemical classification of chemical messengers?

• Amino acids

• Paracrine signaller

• Neurotransmitter

• Hormone

What is the role of gap junctions in direct communication?

• They prevent cells from communicating.

• They connect cells physically for communication.

• They transport nutrients between cells.

• They allow cells to divide.

Which proteins compose the gap junctions?

• Keratin and elastin

• Tubulin and dynein

• Connexin and connexon

• Actin and myosin

What is the main difference between direct and indirect communication?

• Direct communication uses ligands, indirect does not.

• Indirect communication is faster than direct communication.

• Direct communication involves physical connection, indirect does not.

• Indirect communication does not involve receptors.

What happens when a ligand binds to a receptor on a target cell?

• The target cell divides.

• The receptor is deactivated.

• The target cell responds.

• The ligand is destroyed.