Phosphorylation Cascade in Signal Transduction

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What is the main consequence of Cholera toxin permanently activating adenylyl cyclase?

Inhibition of calcium ions production
Enhanced calcium ions uptake into mitochondria
Decreased cAMP production causing dehydration
Increased cAMP production leading to severe diarrhea (correct)

Which statement accurately describes calcium ions' concentration inside the cell?

Actively transported by calcium pumps into the cell
Influencing energy production in the endoplasmic reticulum
Around 100 nanomolar (nM) and typically low (correct)
More than 1000-fold higher compared to outside the cell

How do calcium ions influence cellular responses after flowing out of the endoplasmic reticulum?

Decreasing cAMP production
Inhibiting protein phosphorylation
Enhancing cholesterol synthesis
Activating various proteins (correct)

What role does phospholipase C (PLC) play in the signaling cascade related to calcium ions?

Key player in activating cellular responses (B) Signup and view all the answers

How does Cholera toxin interfere with the phosphorylation cascade pathway?

Permanently activates adenylyl cyclase (D) Signup and view all the answers

What is the role of protein kinases in a phosphorylation cascade?

They add a phosphate group to the next kinase in line. (C) Signup and view all the answers

What is the role of phosphatases in signal transduction via a phosphorylation cascade?

They remove the phosphate group, rendering the protein inactive. (C) Signup and view all the answers

How does cAMP act as a second messenger in signal transduction?

It relays the signal from the receptor to downstream proteins. (D) Signup and view all the answers

What happens when a ligand binds to a GPCR (G protein-coupled receptor) in signal transduction?

It activates adenylyl cyclase. (C) Signup and view all the answers

Where does phosphorylation typically occur within proteins in signal transduction?

At Serine or Threonine residues (C) Signup and view all the answers

What molecule does Phospholipase C (PLC) cleave PIP2 into?

Diacylglycerol (DAG) and IP3 (D) Signup and view all the answers

In signal transduction, what does IP3 bind to?

A gated channel in the Endoplasmic Reticulum (ER) (B) Signup and view all the answers

Why do cells have multiple signaling pathways?

To provide specific responses through different pathways (A) Signup and view all the answers

How do diverse pathways help cells in fine-tuning responses?

By providing multiple control points for adjustment (C) Signup and view all the answers

What analogy is used to explain why different signaling pathways allow for specific responses?

A complex dance where each move matters (C) Signup and view all the answers

What is the role of G Protein coupled receptors (GPCRs) in signal transduction?

They interact with ligands and trigger a downstream phosphorylation cascade. (D) Signup and view all the answers

How do ligand-gated ion channel receptors differ from G Protein coupled receptors (GPCRs) in terms of function?

Ligand-gated ion channels directly open ion channels in response to ligand binding. (A) Signup and view all the answers

Which statement best describes the role of ligand-gated ion channels in cellular processes?

They facilitate the flow of ions across the cell membrane upon ligand binding. (A) Signup and view all the answers

What is the main function of signal transduction via phosphorylation cascade?

Initiating a series of protein modifications to relay a signal within the cell. (C) Signup and view all the answers

How does the specificity of ligand-receptor interactions contribute to effective cellular responses?

By ensuring that only specific cells with particular receptors respond to signals. (D) Signup and view all the answers

What is the role of caffeine in blocking PDEs?

Inhibiting cyclic nucleotide breakdown (A) Signup and view all the answers

How does adrenaline trigger the activation of glycogen phosphorylase?

Through a phosphorylation cascade involving protein kinases (B) Signup and view all the answers

What is the main function of glycogen phosphorylase?

Catalyzing the release of glucose from glycogen (A) Signup and view all the answers

What is the significance of a phosphorylation cascade in signal transduction?

Causing cellular responses through altering protein function (D) Signup and view all the answers

How does caffeine's effect on PDEs relate to cell signaling pathways?

It modulates cyclic nucleotide signaling cascades (B) Signup and view all the answers

What is the primary function of autocrine signaling?

Cells respond to signals they themselves secrete (B) Signup and view all the answers

In endocrine signaling, how do hormones reach their target cells?

Via the circulatory system (blood) (A) Signup and view all the answers

What role does the receptor protein play in signal transduction?

It binds to the signaling protein initiating a response (D) Signup and view all the answers

In signal transduction, what do second messengers like cAMP or IP₃ do?

Participate in a relay of intracellular changes (C) Signup and view all the answers

What analogy best represents the ligand-receptor binding in signal transduction?

A secret handshake between friends (B) Signup and view all the answers

Which type of signaling involves growth factors like fibroblast growth factor (FGF1) acting locally on nearby target cells?

Paracrine Signaling (D) Signup and view all the answers

In cell communication, what is the role of neurotransmitters like acetylcholine (ACh) that zip across synapses?

Transmit electrical signals (A) Signup and view all the answers

How do cells respond when the conductor (external signals) raises the baton in cell signaling?

Cells listen attentively (B) Signup and view all the answers

Which cellular component releases hormones in the process of cell communication?

Endocrine cells (B) Signup and view all the answers

What is the function of stem cells in cell communication?

Await cues for differentiation (A) Signup and view all the answers

Which type of feedback loop in cell signaling keeps the performance in balance?

Negative feedback (D) Signup and view all the answers

What do immune cells do as part of the cellular orchestra in cell communication?

Coordinate defense (C) Signup and view all the answers

In cell signaling, what are neurotransmitters, hormones, and growth factors compared to in the text?

Chemical signals (B) Signup and view all the answers