1. (A)–(II); (B)–(III); (C)–(IV); (D)–(I)

2. (A)–(III); (B)–(IV); (C)–(II); (D)–(I)

3. (A)–(I); (B)–(II); (C)–(IV); (D)–(III)

4. (A)–(III); (B)–(I); (C)–(IV); (D)–(II)

Apoptosis Proteins Matching: Bcl-2, Bax, Rb, EGFR Functions Explained

Bcl-2 family proteins and tumor suppressors like Rb regulate cell survival and growth in cancer biology. This SEO-optimized guide solves Q.52 matching question with the correct answer and breakdowns of all options.

Correct Answer

The correct option is 1. (A)–(II); (B)–(III); (C)–(IV); (D)–(I). Bcl-2 suppresses apoptosis, Bax induces it, Rb suppresses retinoblastoma (cell cycle control), and EGFR acts as a growth factor receptor.

Protein Functions

• Bcl-2 (A): Anti-apoptotic protein that inhibits programmed cell death by blocking mitochondrial cytochrome c release.

• Bax (B): Pro-apoptotic Bcl-2 family member that promotes mitochondrial outer membrane permeabilization to trigger apoptosis.

• Rb (C): Retinoblastoma protein (pRb) acts as a tumor suppressor by binding E2F transcription factors to halt cell cycle at G1/S checkpoint.​

• EGFR (D): Epidermal growth factor receptor, a tyrosine kinase that binds EGF to drive cell proliferation and survival signals.​

Incorrect Options Explained

• Option 2: (A)–(III); (B)–(IV); (C)–(II); (D)–(I) Wrong: Bcl-2 does not induce apoptosis (it’s a suppressor); Bax not a retinoblastoma suppressor; Rb not primarily apoptosis suppressor.

• Option 3: (A)–(I); (B)–(II); (C)–(IV); (D)–(III) Wrong: Bcl-2 not a growth receptor; Bax not suppressor; EGFR not apoptosis inducer.

• Option 4: (A)–(III); (B)–(I); (C)–(IV); (D)–(II) Wrong: Bcl-2 not inducer; Bax not growth receptor; EGFR not apoptosis suppressor.

Key Biology Context

Apoptosis regulation balances Bcl-2 (pro-survival) vs. Bax/Bak (pro-death), while Rb prevents uncontrolled proliferation and EGFR fuels cancer growth. Dysregulation links to tumors like retinoblastoma and lung cancer.