Regulation of Heating and Cooling in PCR
The alternate heating and cooling of reaction mixture in a PCR is regulated by
(a) A heating element and refrigerant
(b) A Peltier device
(c) Electric potential
(d) A heater and chemical coolant
The correct answer is (b) A Peltier device.
✅ Correct Answer: (b) A Peltier device
Explanation
Polymerase Chain Reaction (PCR) requires precise and rapid temperature cycling to enable denaturation, annealing, and extension of DNA. The heating and cooling of the reaction mixture in a PCR machine is controlled by a Peltier device based on the thermoelectric effect.
How a Peltier Device Works
-
Thermoelectric Effect:
- When an electric current passes through the Peltier device, it creates a temperature gradient.
- One side of the device becomes hot, and the other side becomes cold due to the flow of current.
-
Rapid Temperature Cycling:
- The device alternates heating and cooling rapidly by switching the direction of current flow.
- Temperature adjustments can be achieved in seconds.
-
Accuracy and Stability:
- Peltier devices provide high precision, allowing accurate temperature control within ±0.1°C.
- Essential for specific primer binding and DNA polymerase activity.
PCR Cycle and Role of Peltier Device
| Step | Temperature | Purpose | Role of Peltier Device |
|---|---|---|---|
| Denaturation | 94–98°C | DNA strands separate | Heats up rapidly |
| Annealing | 50–65°C | Primers bind to template strand | Cools down rapidly |
| Extension | 72°C | DNA polymerase synthesizes new strand | Maintains stable temperature |
Why Other Options Are Incorrect
| Option | Explanation | Correct/Incorrect |
|---|---|---|
| (a) A heating element and refrigerant | Heating elements are used for heating, but refrigerants are slow and not suitable for PCR. | ❌ Incorrect |
| (b) A Peltier device | Peltier devices allow rapid and precise temperature cycling, essential for PCR. | ✅ Correct |
| (c) Electric potential | Electric potential generates heat but cannot control rapid cooling and heating cycles. | ❌ Incorrect |
| (d) A heater and chemical coolant | Chemical coolants are not suitable for rapid and repeated cycling required in PCR. | ❌ Incorrect |
Advantages of Peltier Devices in PCR
✅ High Precision: Can maintain temperatures within ±0.1°C.
✅ Rapid Cycling: Fast heating and cooling increase PCR efficiency.
✅ Compact Size: Peltier devices are small and integrated into modern thermocyclers.
✅ Durability: Peltier devices are robust and have a long operational lifespan.
Challenges of Using Peltier Devices
- Power Consumption: High energy consumption during rapid cycling.
- Cost: Peltier-based thermocyclers are more expensive than older models.
- Heat Dissipation: Requires effective heat sinks for continuous operation.
Applications of PCR-Based Amplification
✅ 1. Diagnostic Testing
- Detection of viruses (e.g., COVID-19) using RT-PCR.
✅ 2. Forensic Analysis
- DNA fingerprinting for criminal investigation.
✅ 3. Genetic Research
- Amplification of gene sequences for mutation analysis.
✅ 4. Cloning and Gene Editing
- Amplification of target genes for CRISPR experiments.
Summary
- PCR thermocyclers rely on Peltier devices for rapid and accurate temperature cycling.
- The ability of Peltier devices to switch between heating and cooling in seconds enables efficient PCR amplification.
- Peltier-based thermocyclers are widely used in clinical diagnostics, forensic analysis, and genetic research.
76 Comments
Rohit Meena
March 16, 2025Temperature 🌡️
Lokesh kumawat
March 16, 2025Done
Akshay mahawar
March 17, 2025Done 👍
Suman bhakar
March 17, 2025👍👍
Anmol
March 17, 2025Got it
Parul
March 23, 2025Easily done sir.
Ujjwal
March 24, 2025✔️👍
Khushi Pareek
August 23, 2025Peltier device : controls rapid cooling and heating in pcr
Roopal Sharma
August 24, 2025Peltier device regulates cooling and heating in pcr .
Neha Yadav
August 24, 2025Peltier device regulates heating and cooling mixture in a pcr
Soniya Shekhawat
August 24, 2025Pelter devices is a device that allow the rapid and precise temperature which is essential for the PCR.
Mohd juber Ali
August 24, 2025Peltier device regulat the alternate heating and cooling of reaction mixtures
Anurag Giri
August 24, 2025Ans b
Peltier device regulat the alternate heating and cooling of reaction mixtures
Priya dhakad
August 24, 2025Peltier device regulates the heating and cooling rxn mixture in PCR . So option b is correct.
Avni
August 24, 2025Peltier devices allow rapid and precise temperature cycling which is essential for PCR.
Arushi Saini
August 24, 2025Peltier device is used for alternate heating and cooling in pcr
Mansukh Kapoor
August 24, 2025The correct answer is option 2nd
A peltier device while is based on thermoelectric effect helps into controlling the cooling and heating of the mixture in pcr
karishma don
August 24, 2025peltier device which works on thermoelectric effect
Surbhi Rajawat
August 24, 2025A peltier device is used in PCR for rapid heating and cooling as and when required. It is based on thermoelectric principle that is it uses electricity to create a temperature gradient and can reverse the direction also
Aakanksha Sharma
August 24, 2025Peltier device
Dharmpal Swami
August 24, 2025Peltier device is allow rapid and precise temperature cycling to PCR
Yashika Choudhary
August 24, 2025Alternate heating and cooling reaction is for peltier device
Aman Choudhary
August 24, 2025Peltier device regulates the heating and cooling of reaction in mixture
Payal Gaur
August 24, 2025Peltier device used because rapidly heat and cool in reaction mixture
Santosh Saini
August 24, 2025Peltier device regulate heating and cooling of the reaction mixture in a PCR
Karishma
August 24, 2025Peltier device…
Dipti Sharma
August 24, 2025Peltier device regulates heating and cooling in PCR.
Karishma
August 24, 2025Peltier device is regulated heating and cooling in PCR
Karishma
August 24, 2025Peltier device is regulated heating and cooling in PCR….is right answer
Priyanka Choudhary
August 24, 2025B is the right answer,Peltier device regulat the alternate heating and cooling of reaction mixtures
Sneha Kumawat
August 24, 2025A peltier device , cooling and heating ko control karta h
Divya rani
August 24, 2025PCR machine is controlled by a peltier device and it is based on thermoelectric effect which regulate the heat and cooling.
Heena Mahlawat
August 24, 2025Peltier device
MOHIT AKHAND
August 24, 2025Done sir ✅
Neelam Sharma
August 24, 2025Peltier device
Peltier devices provide high precision, allowing accurate temperature control within ±0.1°C.
Essential for specific primer binding and DNA polymerase activity.
anjani sharma
August 24, 2025Answer b
Peltier device- regulates heating and cooling mixture in the process of pcr
Ayush Dubey
August 24, 2025A Peltier device
Shrddha Modi
August 24, 2025Pcr m bar bar denaturation and annealing krnaa padtaa h so we use peltier device
Priyanka Verma
August 24, 2025The correct answer is Peltier device which is based on the thermoelectric effect.
Bharti Yadav
August 24, 2025Peltier devices allow rapid and precise temperature cycling in PCR
Falguni Prakash
August 24, 2025Peltier device
Varsha Tatla
August 24, 2025Peltier device for heating and cooling during pcr
Minal Sethi
August 24, 2025A peltier device
Priti khandal
August 25, 2025Peltire device
shruti sharma
August 25, 2025Peltier device
Mitali saini
August 25, 2025PCR thermocyclers rely on Peltier devices for rapid and accurate temperature cycling.
Anjana sharma
August 25, 2025Peltier device control the temperature during polymerase chain reaction
Vanshika Sharma
August 25, 2025Peltier device regulate the heating and cooling during pcr
Surendra Doodi
August 25, 20252nd option A Peltier device
Bhavana kankhedia
August 26, 2025a Peltier device
Nilofar Khan
August 26, 2025Correct answer is b
A peltier device for alternative heating and cooling of reaction mixture in a PCR
Manisha
August 26, 2025Done with explanation..
Devika
August 26, 2025Peltier device Best Institute for CSIR NET Life Science Coaching – Let’s Talk Academy”
Alec
August 26, 2025Peltier device regulates cooling and heating in pcr.
Rishita
August 26, 2025Done
Pallavi Ghangas
August 26, 2025Alternate heating and cooling in PCR is achieved by using peltier device
Mohini
August 27, 2025B) Peltier device
Kanica Sunwalka
August 28, 2025only peltier device – able to do rapid alteration bw heating and cooling
Kajal
August 28, 2025Correct answer is option b peltier device is used in PCR for temperature control
Muskan singodiya
August 28, 2025Option b
Peltier device
Deepika sheoran
August 28, 2025Option b is correct
Peltier Device= controls rapid cooling & Heating in PCR.
Neeraj Sharma
August 28, 2025Peltier device is used for heating and cooling in pcr so option b is correct
Anisha Beniwal
August 28, 2025Option B is correct
Parul Yadav
August 29, 2025The alternate heating and cooling of the reaction mixture in PCR is regulated by a Peltier device.
Asha Gurzzar
August 30, 2025Peltier device used for heating and cooling in pcr as it maintains the rapid and precise heating and cooling
Yogita
August 30, 2025Peltier device
Khushi Singh
August 30, 2025Peltier device gives thermoelectric effect.
Sonam Saini
August 30, 2025A platry device
Sonam Saini
August 30, 2025A peltier divice
Alec
August 30, 2025A peltier device is used.
Kirti Agarwal
August 31, 2025Peltier device
Sakshi yadav
August 31, 2025Peltier device is used in the cooling and heating in pcr
Kajal
August 31, 2025Correct Answer is(b) A Peltier device
Aartii sharma
August 31, 2025A peltier device
Meenakshi Choudhary
September 4, 2025Peltier device is used for heating and cooling in pcr so option b is correct.
Muskan Yadav
September 5, 2025The heating and cooling of the reaction mixture in a PCR machine is controlled by a Peltier device based on the thermoelectric effect.