Prepare for NEET Biology Chemical Coordination and Integration (Mechanism Of Hormonal Action) with MCQs & PYQs on NEET.GUIDE. Access free practice, previous year questions, and expert help to understand receptor binding, second messengers, and feedback loops.
NEET Questions / Zoology / Chemical Coordination and Integration / Mechanism Of Hormonal Action
A researcher discovers a novel hormone that utilizes a tyrosine kinase-linked receptor. Which of the following is LEAST likely to be a downstream effect of this hormone binding to its receptor?
Phosphorylation of intracellular proteins
Activation of a cascade of protein kinases
Changes in gene expression
Direct activation of adenylate cyclase
Certain hormones can exert their effects by altering the permeability of the cell membrane to specific ions. Which of the following scenarios is LEAST likely to be a direct result of such a mechanism?
Changes in membrane potential
Influx of calcium ions leading to muscle contraction
Release of neurotransmitters
Activation of a nuclear receptor
Which of the following is NOT a characteristic of steroid hormone action?
Binding to intracellular receptors
Regulation of gene expression
Long-lasting effects
Rapid onset of action
A hormone's effect is amplified within the cell due to a cascade of events. This amplification is primarily attributed to:
The high affinity of the hormone for its receptor
The presence of multiple receptors for the hormone on each cell
The activation of multiple enzymes by a single hormone-receptor complex
The rapid internalization of the hormone-receptor complex
Hormone X activates a G protein-coupled receptor, which in turn activates adenylate cyclase. A drug that inhibits phosphodiesterase would likely have what effect on the cellular response to hormone X?
Inhibit the response by decreasing cAMP levels
Enhance the response by increasing cAMP levels
No effect on the response
Inhibit the response by blocking the hormone-receptor interaction
Which characteristic distinguishes the mechanism of action of peptide hormones from steroid hormones?
Peptide hormones directly regulate gene expression, while steroid hormones activate second messenger systems.
Peptide hormones bind to intracellular receptors, while steroid hormones act through cell surface receptors.
Peptide hormones primarily act through cell surface receptors, while steroid hormones bind to intracellular receptors.
Both peptide and steroid hormones utilize the same receptor types and signaling pathways.
Which of the following statements is INCORRECT regarding the mechanism of steroid hormone action?
Steroid hormones bind to intracellular receptors.
The hormone-receptor complex interacts directly with DNA.
Steroid hormones do not require a second messenger system.
Steroid hormone action is typically rapid compared to peptide hormones.
The primary function of secondary messengers in hormone action is to:
Transport hormones across the cell membrane.
Bind directly to DNA and regulate gene expression.
Amplify the hormonal signal and initiate intracellular responses.
Inhibit the binding of hormones to their receptors.
Which hormone utilizes the adenylate cyclase-cAMP second messenger system?
Insulin
Glucagon
Thyroxine
Cortisol
Hormone receptors exhibit high specificity. This means that:
Hormones can bind to any receptor on the cell surface.
Each receptor binds only to a specific hormone.
Receptors can bind to multiple hormones simultaneously.
Hormones can elicit any cellular response regardless of the receptor.
