The Question is from neet-botany biomolecules-biology , and it was created by the author NISHANTH

Question

A novel protein was discovered containing a unique amino acid with a side chain composed of a selenol group (-SeH).  Compared to a cysteine residue (-SH) in a similar protein, this selenol-containing amino acid would MOST likely exhibit which property?

NISHANTH · Accepted Answer

## CORE INFORMATION
✓ **Answer**: A
## CONCEPT FRAMEWORK
 **Primary Concept**: Redox chemistry of thiols and selenols
 **Related Topics**:  Amino acid properties, protein structure, oxidation-reduction reactions
 **Prerequisites**: Understanding of electronegativity and bond strengths.
## SOLUTION PATHWAY
**Given Information**:
A novel amino acid with a selenol (-SeH) group is compared to cysteine (-SH).
**Method & Steps**:
1. Compare the reactivity of Se and S towards oxidation.
  Reasoning: Selenium (Se) is larger and less electronegative than sulfur (S).  This makes the Se-H bond weaker than the S-H bond. Weaker bonds are more easily broken.
  Formula/Rule:  Oxidation involves the loss of electrons.  Selenols are more easily oxidized than thiols.
2. Consider the products of oxidation.
  Working:  Both selenols and thiols can be oxidized to form diselenides (-Se-Se-) and disulfides (-S-S-), respectively. However, selenols are oxidized more readily.
  Key Point: The weaker Se-H bond contributes to increased reactivity towards oxidizing agents.
3. Determine the most likely property.
  Result: The selenol-containing amino acid would exhibit increased reactivity towards oxidizing agents.
  Verification: The increased reactivity is consistent with the weaker Se-H bond and the lower electronegativity of selenium compared to sulfur.
 ## OPTION ANALYSIS
A ✓: Increased reactivity towards oxidizing agents: Correct. Selenols are more easily oxidized than thiols due to the weaker Se-H bond.
B :x: Decreased reactivity towards oxidizing agents: Incorrect. The weaker Se-H bond leads to increased reactivity.
C :x: Identical reactivity towards oxidizing agents: Incorrect. Selenium and sulfur have different chemical properties.
D :x: Formation of stronger disulfide bonds: Incorrect.  It forms diselenide bonds, which are generally weaker than disulfide bonds.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing electronegativity trends: Remember that electronegativity decreases down a group in the periodic table.
  2.Overlooking bond strength differences: The difference in bond strength between Se-H and S-H is crucial for understanding the reactivity difference.
 **Quick Tips**:
  1.Remember that weaker bonds are more reactive.
  2.Selenium is below sulfur in the periodic table, thus exhibiting different properties.

NISHANTH · Answer

The correct Option is "Increased reactivity towards oxidizing agents"

NISHANTH · Answer

Decreased reactivity towards oxidizing agents

NISHANTH · Answer

Identical reactivity towards oxidizing agents

NISHANTH · Answer

Formation of stronger disulfide bonds

NEET Botany Biology Biomolecules MCQs

Select Topic

Question Tags

NEET Subjects

Our Bots

Company