Cell Signaling and Signal Transduction

Cell signaling and Signal transduction for AP biology.

What is the significance of cell signaling in organisms?

It’s crucial for coordinating activities and responding to environmental changes.

How does cell signaling differ between organisms?

In unicellular organisms, it influences how the cell responds to the environment, while in multicellular organisms, it coordinates activities within cells to support overall function.

What is the most common type of signal used for cell communication?

Chemical

What are the two main types of signaling based on distance?

Local and long distance.

What is juxtacrine signaling?

Direct physical contact between cells without the secretion of signaling molecules.

What role do plasmodesmata and gap junctions play in local signaling?

They allow for the exchange and transport of materials in adjacent cells.

What is autocrine signaling?

When a cell secretes a chemical that targets itself.

What is paracrine signaling?

Cells secreting molecules that affect nearby cells.

What is quorum sensing in bacteria?

A process that allows them to coordinate their behaviors based on local cell density.

What are morphogens and their role in embryonic development?

Ligands that influence cell differentiation based on their concentration and the activation of cell receptors.

What is the function of neurotransmitters in synaptic signaling?

They are secreted between nerve cells to transmit signals or induce muscle contractions.

What is endocrine signaling?

The secretion of hormones into the bloodstream to target distant cells.

What is the role of insulin in long distance signaling?

When secreted by the pancreas it signals cells to transport glucose, aiding in energy use.

How does human growth hormone affect growth and development?

It stimulates growth in bones and muscles and increases energy availability by signaling fat and liver cells.

What are pheromones and their function?

Chemical signals released outside an organism to induce physiological or behavioral changes in others of the same species.

What are embryonic stem cell markers?

Molecules on the surface of embryonic stem cells that signal to adjacent cells, guiding differentiation.

What is the function of the thyroid gland in signaling?

It produces hormones that regulate metabolic activity and cell proliferation.

What is the role of nitric oxide during physical activity?

It’s released by endothelial cells to relax smooth muscle and increase blood flow.

How does acetylcholine function in muscle contraction?

It’s released by motor nerves to bind to receptors on skeletal muscles, causing contraction.

What is the significance of auxins in plant growth?

They’re hormones that mediate growth and development, requiring plasmodesmata for transport.

What is the role of epidermal growth factor (EGF) in wound healing?

It signals surrounding cells to grow, proliferate, and differentiate during the healing process.

What are signal transduction pathways?

Series of steps in which a signal outside the cell is converted into a specific cellular response.

What are the three stages of signal transduction?

Reception, Transduction, and Response.

What is a ligand?

A small chemical messenger that binds to specific receptor proteins to produce a response in a cell.

What are intracellular receptors?

Proteins located inside the target cell that bind to small, nonpolar, and hydrophobic ligands.

What are membrane receptors and what roles do they play?

They’re integral proteins with a ligand binding domain outside the cell that bind to large, polar, and hydrophilic ligands.

What is allosteric regulation in signal reception?

The binding of a ligand to a receptor protein causes a change in the receptor's conformation, affecting its activity.

What is a phosphorylation cascade?

A series of protein kinases phosphorylating and activating other kinases, amplifying the signal.

What is the function of protein kinases?

Enzymes that transfer phosphate groups from ATP to proteins, activating them.

What do are protein phosphatases and what do they do?

Enzymes that remove phosphate groups from activated molecules, turning them off or inactivating them.

What are secondary messengers?

Small, non-protein, hydrophilic molecules or ions that activate proteins involved in the transduction pathway.

What is the role of cyclic AMP (cAMP) in signal transduction?

It activates protein kinase A, which initiates phosphorylation cascades or activates other cellular molecules.

How is IP3 involved in signal transduction?

It activates calcium channels, allowing Ca2+ to diffuse into the cytoplasm and activate proteins for cellular responses.

What is signal amplification?

The process where each step in a signal transduction pathway results in a greater number of activated products.

What determines the specificity of a cellular response to a signal?

The particular collection of signal receptor proteins, relay proteins, and proteins needed for the response in the cell.

What is the G-protein coupled receptor (GPCR) pathway?

A signaling system where ligand binding activates a G-protein, triggering a cellular response.

What is the function of tyrosine-kinase receptors?

They’re membrane receptors that can activate multiple transduction pathways and cellular responses simultaneously.

What happens when a ligand binds to a ligand-gated ion channel?

The channel opens, allowing ions to flow through and initiate a signal transduction pathway.

What is the role of scaffolding proteins in signal transduction?

They hold multiple important relay proteins close together, increasing the efficiency of signal transduction.

How do cellular responses vary?

They can occur in the nucleus or cytoplasm and may involve regulating protein synthesis or enzyme activity.

What is the significance of reversible ligand-receptor binding?

It allows the target cell to stop responding to the signal after the appropriate response has occurred.

What is the role of adenylyl cyclase in cAMP production?

It converts ATP to cAMP in response to signal reception, activating downstream signaling pathways.

What is the function of phosphodiesterase in relation to cAMP?

It converts cAMP back to inactive AMP, regulating the levels of cAMP in the cell.

What is the role of calcium ions (Ca2+) in cellular responses?

They activate various proteins involved in processes like muscle contraction and cell division.

What is the importance of signal transduction pathways in cellular communication?

They allow cells to respond to external signals, coordinating complex cellular activities.