Cellular Signaling Mechanisms

Professor Dave explains how cells communicate through receptors, which are proteins that receive signals from outside the cell. These signals, often in the form of ligands like hormones, bind to receptors and cause conformational changes that trigger various cellular responses. The video covers signal transduction pathways, receptor-mediated endocytosis, and intracellular receptors, highlighting how these processes regulate gene expression, metabolism, and cell division.

What is the primary function of receptors in cellular communication?

• To produce energy for the cell

• To store genetic information

• To receive and process information from outside the cell

• To transport nutrients across the cell membrane

What is a ligand in the context of cellular receptors?

• A type of cell

• A molecule that binds to a receptor

• A protein that transports signals

• A type of enzyme

What role do G proteins play in signal transduction?

• They bind to enzymes to trigger further signaling

• They act as receptors on the cell surface

• They store genetic information

• They transport nutrients into the cell

What is the function of second messengers in cellular signaling?

• To directly bind to DNA

• To transport oxygen

• To amplify the signal within the cell

• To break down proteins

What occurs during a phosphorylation cascade?

• Molecules exchange phosphate groups in a chain reaction

• Cells divide uncontrollably

• Proteins are synthesized

• DNA is replicated

What is receptor-mediated endocytosis?

• The process of receptors releasing ligands

• The absorption of bulk substances through receptor clustering

• The breakdown of cellular waste

• The synthesis of new proteins

Where are intracellular receptors typically located?

• On the cell surface

• In the cell wall

• In the cytoplasm or nucleus

• In the mitochondria

What type of molecules can pass through the plasma membrane to reach intracellular receptors?

• Small and nonpolar molecules

• Proteins

• Large and polar molecules

• Ions

How can signaling molecules influence gene expression?

• By storing energy

• By acting as transcription factors

• By transporting proteins

• By breaking down DNA

What can happen if a signal to stop cell division is not received?

• The cell will change shape

• Tumor growth may occur

• The cell will produce more energy

• The cell will become dormant