What is the basis of isoelectric focusing separation of protein.
(a) Relative content of positively charged residues only
(b) Relative content of negatively charged residues only
(c) Size
(d) Relative content of positively and negatively charged residues
The correct answer is:
(d) Relative content of positively and negatively charged residues
Explanation:
- Isoelectric focusing (IEF) separates proteins based on their isoelectric point (pI), which is the pH at which a protein has no net charge.
- Proteins contain both positively charged (basic) residues (e.g., lysine, arginine, histidine) and negatively charged (acidic) residues (e.g., aspartic acid, glutamic acid).
- During IEF, proteins migrate in a pH gradient under an electric field until they reach their pI, where their net charge is zero and they stop moving.
Why Not the Other Options?
- (a) Relative content of positively charged residues only → Incorrect because both positive and negative charges influence the pI, not just positive residues.
- (b) Relative content of negatively charged residues only → Incorrect because proteins also have basic residues that contribute to their net charge and pI.
- (c) Size → Incorrect because IEF does not separate proteins by size, unlike SDS-PAGE or gel filtration.
Conclusion:
Isoelectric focusing depends on the balance of both positive and negative charges in a protein, making option (d) correct.



66 Comments
Prami Masih
February 27, 2025Okay sir
Akshay mahawar
March 19, 2025Done 👍
Arushi
April 2, 2025👍✔️
Anita choudhary
April 18, 2025Done 👍✅
Aman Choudhary
August 13, 2025option d is correct Relative content of positively and negatively charged residues
Mohd juber Ali
August 14, 2025Option (4)
Protein content both positive and negative charge
° positive=basic accept H+ ion
° negative= acidic release H+ ion
IEF seprate protein on the basis of charge or PI
In IEF protein migrate in pH gradient until reach their PI
Monika meena
August 27, 2025Both positively and negatively charge
shruti sharma
August 14, 2025d is correct
Mahima Sharma
August 24, 2025Relative content of positivity and negativity charge reduce
Khushi Agarwal
August 14, 2025Option 4 is correct bcz
Net charge is zero
Dharmpal Swami
August 14, 2025On the basis of charge molecules [+.-]
Anurag Giri
August 14, 2025Ans 4 Isoelectric focusing depends on the balance of both positive and negative charges in a protein
Priya dhakad
August 14, 2025Isoelectric focusing depends on the balance of both positive and negative charges in a protein.
Neelam Sharma
August 14, 2025Relative content of positively and negatively charged residues
Devika
August 14, 2025Done sir positive and negative both ke basis pr separation hota h
Soniya Shekhawat
August 14, 2025Done sir ✅
Mansukh Kapoor
August 14, 2025The correct answer is option 4th The relative content of positive and negative charge content residue
IEF is the technique which separates the protein on the basis of pH where the net charge becomes zero and protein stops in the pH gradient
Pratibha sethiya
August 14, 2025Correct answer is 4
IEF separates proteins based on the pH at which the net charge on a protein is zero
Pratibha sethiya
August 14, 2025Correct answer is 4
Relative content of positive and negative charge residue
IEF separates proteins based on the pH at which the net charge on a protein is zero
Aafreen
August 14, 2025Ans-4
Relative content of positively and negatively charged residues
IEF is the technique which separates the protein on the basis of pH ,the net charge is zero
Dipti Sharma
August 14, 2025The pH at which a protein has no net charge is IEF as
Proteins contain both positively charged and negatively charged residues correct answer is 4
Manisha gujar
August 14, 2025IEF separate the protein on basis of positive and negative charged
Karishma
August 14, 2025relative content of +VEly and -vely charged residues
Priti khandal
August 14, 2025option d is right because IEF is the technique which separate the protein on the basis of PH the net charge of zero and relative content of positively and negatively Charged residues
Priya khandal
August 14, 2025Relative content of positively and negatively charged residues
Roopal Sharma
August 14, 2025Done
Deepika Sheoran
August 15, 2025Option 4th is correct answer
Releative content of positive & Negative charge residue. Net charge on a protein is zero.
Santosh Saini
August 15, 2025Option 4th is correct bcz IEF = separation of protein on the basis of iso electric point (pi) or change so net charge is zero (positive and negative charge reduced)
Priyanka choudhary
August 16, 2025Correct answer is option d, because net charge hi 0
Nilofar Khan
August 16, 2025Correct answer is d
Manisha choudhary
August 17, 2025Done sir
Protein p negative and positive charge dono hota h protein ph gradient p electric charge ki presence m move krti h isliye pi value tk
Pi value = ph at which net charge on protein is zero
Kavita choudhary
August 17, 2025Relative contant of positive and negative charge reduse because net charge is zero
Surbhi Rajawat
August 17, 2025IEF is basically a technique to identify the Pi of a protein which is the ph at which it’s neutral. And neutrality of anything depends upon the relative content of both positive and negative charge. Hence answer is D
Kajal
August 17, 2025Relative content of positively and negatively charged protein
Avni
August 17, 2025Relative content of positively and negatively charged residue
Varsha Tatla
August 19, 2025IEF is a protin sep. Tech on the basis of isoilectric point PI means which have +ve basic or -ve acidic amino acid residue
Easily seprate by IEF
Sneha .......
August 20, 2025D is correct
Bhavana Kankhedia
August 24, 2025relatively content of positively and negatively charged residues
Bharti Yadav
August 24, 2025Isoelectric focusing depends on both positive and negative charges in a protein
Payal Gaur
August 24, 2025Relative content positively and negatively charge residue
Priyanka Choudhary
August 24, 2025Option d is correct answer because the Relative content of positively and negatively charged residues,and the net charge will be 0
Sonan saini
August 24, 2025D is Right answer
Niti Tanwar
August 24, 2025D is right answer
Alec
August 24, 2025option d – relative content of positively and negatively charged molecules.
Anjali
August 24, 2025Option d is correct bcz net charge is 0
Falguni Prakash
August 24, 2025Option d. Coz it depends on both charge
Sakshi
August 24, 2025Relative content of negative and positive charge residue is correct
Vijay kumar Meena
August 24, 2025D ✔️ 👍
Devika
August 25, 2025Relative content of positively and negatively charged residues
Kashish yadav
August 25, 2025Option d
sakshi khatri
August 25, 2025done
Shivani Panwar
August 25, 2025Relative content of positively and negatively charged molecule
Ayush Dubey
August 25, 2025Relative content of positively and negatively charged residues
Pratibha Jain
August 30, 2025Correct answer is option (d)
Relative content of positively and negatively charged residues
Sheikh Aleen
August 30, 2025Relative content of positively and negatively charged residues
Anisha Beniwal
August 30, 2025Relative content of positively and negatively charged residues
Vanshika Sharma
August 30, 2025Iso electric focusing seperate protiens on the basis of their isoelectric point at which net charge is zero
anjani sharma
August 30, 2025Answer d
Relative content of positively and negatively charged residues
Akshita Jangid
August 31, 2025Isoelectric focusing depends on the balance of both positive and negative charges in a protein
Shobha Kanwar
August 31, 2025Correct answer is 4 bcoz IEF separates proteins based on the pH at which the net charge on a protein is zero
Asha Gurzzar
August 31, 2025D is correct relative content of both type charges residues
Anisha jakhar
September 3, 2025(d) Relative content of positively and negatively charged residues
Muskan Yadav
September 3, 2025Relative content of positively and negatively charged residues.
Somya Yadav
September 5, 2025Relative content of positively and negatively charged residues
Aakansha sharma Sharma
October 1, 2025The correct answer is:
(d) Relative content of positively and negatively charged residues
Vanshika Sharma
January 16, 2026Relative content of positively and negatively charged residues