Assertion (A) : Some cell signalling receptor are at the cell surface with transmembrane domains that help them embed in the plasma membrane.
Reason (R) : They are localized at the cell surface as their activating ligands cannot enter the cell interior.
In the light of the above statements, choose the most appropriate answer from the options given below :
Analysis of Cell Signalling Receptor Statements
This question involves evaluating two statements about cell signalling receptors, Assertion (A) and Reason (R), to determine their validity and relationship.
Evaluating Assertion (A)
Assertion (A) states that some cell signalling receptors are located at the cell surface and possess transmembrane domains.
- Cell surface receptors are a well-known class of receptors involved in transmitting signals from the extracellular environment into the cell.
- A key structural feature of many cell surface receptors is the presence of one or more transmembrane domains, which anchor the receptor protein within the lipid bilayer of the plasma membrane.
Therefore, Assertion (A) is factually correct.
Evaluating Reason (R)
Reason (R) suggests that these receptors are at the cell surface because their activating ligands cannot enter the cell interior.
- Many signalling molecules (ligands), such as peptide hormones and growth factors, are hydrophilic and cannot freely cross the hydrophobic lipid bilayer of the cell membrane.
- For these extracellular ligands to trigger a cellular response, receptors must be accessible on the cell surface to bind them.
This explains the necessity of cell surface receptors for such ligands. Therefore, Reason (R) is also factually correct.
Relationship Between Assertion (A) and Reason (R)
Reason (R) explains *why* receptors are located at the cell surface—because the signalling molecules (ligands) that activate them are unable to cross the plasma membrane. Assertion (A) describes the structural characteristic (transmembrane domains) of these cell surface receptors that allows them to be embedded in the membrane. The need for surface localization (explained by R) directly leads to the structural requirement for membrane anchoring (described in A). Thus, Reason (R) provides a correct and logical explanation for Assertion (A).
Conclusion
Both Assertion (A) and Reason (R) are correct, and Reason (R) is the correct explanation for Assertion (A).
Similar Questions
- Primary changes in Acid Base disorders are :
A. Metabolic acidosis decreased plasma bicarbonate
B. Metabolic alkaloses decreased plasma bicarbonate
C. Respiratory alkalosis decreased $pco_{2}$
D. Respiratory acidosis decreased $pco_{2}$
Choose the correct answer from the options given below : - Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : A covlent single bonds in biological molecules have energies similar to the energy of the C-C bond in ethane.
Reason (R) : It is because less electrons are shared between atoms in double bonds they require more energy to break than single bonds.
In the light of the above statements, choose the most appropriate answer from the options given below : - A solution is called hypertonic when :
List - I shows various isotopes and List - II indicates their half-lives.
Match List - I with List - II.
List - I List - II A. ${ }^{3}\text{H}$ I. 60 days B. ${ }^{14}\text{C}$ II. 14.5 days C. ${ }^{32}\text{P}$ III. 5700 years D. ${ }^{125}\text{I}$ IV. 12.2 years
Choose the correct answer from the options given below :- Based on the position of Centromere Chromosome can be divided into 4 types :
A. Meta centric : Centromere in the middle
B. Submetacentric : Centromere at the end
C. Telocentric : Terminal Centromere
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Choose the correct answer from the options given below : - Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Neurons are the functional cells in brain. Glial cells are the supporting cells of the brain.
Reason (R) : Astroglia are starshaped neuronal cells.
In the light of the above statements, choose the most appropriate answer from the options given below : - Which of the following are the correct components of PCR reation ?
A. Taq Polymerase
B. Buffer (5X)
C. Primers (F and R)
D. NTPs
E. $\\text{H}_{2}\\text{O}$
Choose the correct answer from the options given below : - List the proteins detection techniques in increasing order of sensitivity :
A. Bradford
B. Biuret
C. Lowry
Choose the correct answer from the options given below : - Match List - I with List - II.
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Choose the correct answer from the options given below : - Match List - I with List - II.
List - I List - II A. SDS-PAGE I. DNA B. Agarose gel electrophoresies II. Liquid chromatography C. Native Page III. Non-denatured proteins D. HPLC IV. proteins
Choose the correct answer from the options given below :
Important Questions from Mixed Topic (CUET PG)
- Who was the founder of Bolshevik Communist party?
- What is the key guide to statecraft in the realist tradition?
- Chronologically arrange the events in the Cold War period.
A. Berlin Wall is constructed
B. Communist China joins the UN
C. Soviet invasion of Czechoslovakia
D. Berlin Blockade
Choose the correct answer from the options given below: Morgenthau's principles of political realism are:
A. Politics is rooted in permanent and unchanging human nature which is basically self centred, self-regarding and self-interested
B. Politics is an autonomous sphere of action and cannot therefore be reduced to morals
C. International Politics is an arena of conflicting self-interests
D. The ethics of international relations is situational ethics which is very different from private morality
Choose the correct answer from the options given below:Who among the following political thinkers consider the anarchical self help system to be a compelling factor for States to maximise their relative power positions?
