C2.1 Cell Signalling (HL only) SV

What type of molecules are considered ligands in chemical signaling?

• Proteins
• Lipids
• Gases
• Amino acids

Answer explanation

Ligands include a variety of molecules such as proteins, small peptides, amino acids, nucleotides, steroids, amines, and gases like nitric oxide, crucial for cellular communication and response.

How do receptor proteins on the cell surface interact with ligands?

• Bind to specific ligands
• Repel ligands
• Destroy ligands
• Synthesize ligands

Answer explanation

Receptor proteins on the cell surface have unique structures that allow them to bind specifically to ligands, which is essential for the targeted cellular response in signal transduction.

What is a secondary messenger in cellular signaling?

• An intracellular signal
• A type of ligand
• An external receptor
• A DNA molecule

Answer explanation

A secondary messenger is a molecule inside the cell that helps propagate the signal initiated by the binding of a ligand to its receptor, playing a crucial role in further cellular responses like enzyme activation.

What does quorum sensing determine in bacteria?

• Population density for activity
• Cell size
• Nutrient levels
• Waste removal

Answer explanation

Quorum sensing is a mechanism in bacteria that checks the population density to decide if it is large enough to initiate a collective activity, influencing gene expression and behavior.

What are the typical ligands for intracellular receptor proteins?

• Steroid hormones
• Water molecules
• Lipid-soluble molecules
• Gases

Answer explanation

Intracellular receptors bind to non-polar, lipid-soluble ligands, such as steroid hormones, which can diffuse through the plasma membrane, affecting gene expression and cell function.

What does the activation of a transmembrane receptor typically result in?

• Signal transduction
• Ligand release
• Energy production
• Receptor degradation

Answer explanation

Activation of a transmembrane receptor leads to signal transduction across the membrane, affecting cellular functions by initiating further signaling events inside the cell.

Which ions are involved in neurotransmitter secretion in neurons?

• Calcium ions
• Potassium ions
• Sodium ions
• Magnesium ions

Answer explanation

Calcium ions facilitate the exocytosis of neurotransmitters into the synaptic gap in neurons, playing a key role in neural communication and muscle contraction.

What is the primary role of cytokines?

• Signaling in immune responses
• Energy storage
• Muscle contraction
• Lipid transport

Answer explanation

Cytokines are small proteins that act as signaling chemicals involved in immune responses, cell growth, and development, acting locally on the secreting cell or nearby cells.

Tags

NGSS.HS-LS1-3

What is the difference between hormones and neurotransmitters in their mode of action?

• Duration and speed of action
• Molecular structure
• Origin of secretion
• Receptor types

Answer explanation

Hormones generally act over longer periods and are transported by the bloodstream, while neurotransmitters act quickly across synaptic gaps, highlighting their different roles in cellular communication.

Which cellular function is directly influenced by steroid hormones?

• Gene transcription
• Protein synthesis
• Lipid metabolism
• Enzyme activity