diff --git a/backend/src/controllers/biochemController.js b/backend/src/controllers/biochemController.js
index d5ef6f1..0e927c3 100644
--- a/backend/src/controllers/biochemController.js
+++ b/backend/src/controllers/biochemController.js
@@ -1,6 +1,6 @@
 'use strict';
 const db = require('../db/db');
-const { awardXP } = require('./gamificationController');
+const { awardXP, checkAchievements } = require('./gamificationController');
 
 /* ── Helpers ─────────────────────────────────────────────────────────── */
 const MAX_V = { H:1, C:4, N:3, O:2, P:5, S:6, Cl:1, Na:1, Ca:2, K:1, Mg:2, Fe:3, Br:1, I:1, F:1 };
@@ -178,6 +178,7 @@ function solveChallenge(req, res) {
       return res.status(400).json({ error: 'wrong_answer' });
     stmts.markDone.run(req.user.id, challenge.id);
     awardXP(req.user.id, challenge.xp_reward, `biochem_challenge:${challenge.id}`);
+    checkAchievements(req.user.id);
     return res.json({ ok: true, xp: challenge.xp_reward });
   }
 
@@ -190,6 +191,7 @@ function solveChallenge(req, res) {
       return res.status(400).json({ error: 'wrong_answer' });
     stmts.markDone.run(req.user.id, challenge.id);
     awardXP(req.user.id, challenge.xp_reward, `biochem_challenge:${challenge.id}`);
+    checkAchievements(req.user.id);
     return res.json({ ok: true, xp: challenge.xp_reward });
   }
 
@@ -203,6 +205,7 @@ function solveChallenge(req, res) {
       return res.status(400).json({ error: 'wrong_answer' });
     stmts.markDone.run(req.user.id, challenge.id);
     awardXP(req.user.id, challenge.xp_reward, `biochem_challenge:${challenge.id}`);
+    checkAchievements(req.user.id);
     return res.json({ ok: true, xp: challenge.xp_reward });
   }
 
@@ -216,6 +219,7 @@ function solveChallenge(req, res) {
       return res.status(400).json({ error: 'wrong_answer' });
     stmts.markDone.run(req.user.id, challenge.id);
     awardXP(req.user.id, challenge.xp_reward, `biochem_challenge:${challenge.id}`);
+    checkAchievements(req.user.id);
     return res.json({ ok: true, xp: challenge.xp_reward });
   }
 
@@ -230,6 +234,7 @@ function solveChallenge(req, res) {
       return res.status(400).json({ error: 'wrong_answer' });
     stmts.markDone.run(req.user.id, challenge.id);
     awardXP(req.user.id, challenge.xp_reward, `biochem_challenge:${challenge.id}`);
+    checkAchievements(req.user.id);
     return res.json({ ok: true, xp: challenge.xp_reward });
   }
 
@@ -244,6 +249,7 @@ function solveChallenge(req, res) {
       return res.status(400).json({ error: 'wrong_answer' });
     stmts.markDone.run(req.user.id, challenge.id);
     awardXP(req.user.id, challenge.xp_reward, `biochem_challenge:${challenge.id}`);
+    checkAchievements(req.user.id);
     return res.json({ ok: true, xp: challenge.xp_reward });
   }
 
@@ -274,6 +280,7 @@ function solveChallenge(req, res) {
 
   stmts.markDone.run(req.user.id, challenge.id);
   awardXP(req.user.id, challenge.xp_reward, `biochem_challenge:${challenge.id}`);
+  checkAchievements(req.user.id);
   res.json({ ok: true, xp: challenge.xp_reward });
 }
 
@@ -303,6 +310,7 @@ function saveMolecule(req, res) {
     JSON.stringify(atoms),
     JSON.stringify(bonds),
   ).lastInsertRowid;
+  checkAchievements(req.user.id);   // bc_first_molecule
   res.status(201).json({ id, formula, known: known || null });
 }
 
diff --git a/backend/src/controllers/gamification/service.js b/backend/src/controllers/gamification/service.js
index 119d87e..0c222f8 100644
--- a/backend/src/controllers/gamification/service.js
+++ b/backend/src/controllers/gamification/service.js
@@ -343,6 +343,19 @@ function checkPhase3Achievements(userId, userRow) {
     if (tb) unlockAchievement(userId, 'tb_first_para');
   } catch (e) { /* table missing */ }
 
+  // ── biochem: решённые задачи + первая собранная молекула ───────
+  try {
+    const bc = db.prepare(`
+      SELECT COUNT(*) AS n FROM bio_user_challenges WHERE user_id = ?
+    `).get(userId)?.n || 0;
+    if (bc >= 5)  unlockAchievement(userId, 'bc_5_challenges');
+    if (bc >= 20) unlockAchievement(userId, 'bc_20_challenges');
+    const mol = db.prepare(`
+      SELECT 1 FROM bio_user_molecules WHERE user_id = ? LIMIT 1
+    `).get(userId);
+    if (mol) unlockAchievement(userId, 'bc_first_molecule');
+  } catch (e) { /* bio tables missing on legacy install */ }
+
   // ── flashcards: total reviews ──────────────────────────────────
   try {
     const fc = db.prepare(`