UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
How it Works
Ask a Question
Search Topics
Our Scientists
Science Links
Contact Information
It is known that living cells can, to some extent, repair their DNA. Do you think this process can be done without using some form of energy?
Question Date: 2004-04-15
Answer 1:

DNA repair mechanisms are a common and important part of cellular life. There are a number of "sensing" mechanisms that a cell may use to detect DNA damage. If the damage is irreparable,these cells often undergo cell death by a process called "apoptosis." In fact, many cancers are thought to be the results of "mistakes" in the sensing and checking processes -- a cell with damaged/mutated DNA is able to escape death and thus becomes cancerous.

As you might imagine, the DNA repair machinery(which is fairly well described and studied) in the cell involves enzymes that can cut and re-ligate the nucleic acid strands. And this requires energy to do so. To my knowledge, there is no form of DNA repair that does not require energy. I am curious as to why you ask the question --does it have something to do with the idea that DNA replication has such high fidelity and is a"template" directed process? Or that it is a biological polymer that might be described as"self healing"?

Answer 2:

DNA repair, like every active cellular process, requires energy. In fact,the laws of physics tell us that everything, every single thing, that maintains order in the universe requires energy.

DNA with a specific sequence is more orderly than DNA with a random sequence, so energy must be spent to maintain that order. Keeping your room clean is maintaining order,too, and it also requires energy. That energy comes to you in the form of the food you eat. In the case of DNA repair, the energy comes from the heat required to keep the repair enzymes active, and in the ATP that goes into breaking and reforming the bonds that hold the DNA molecules together.

Questions like yours are why it's important for biology students to take physics!

Answer 3:

Cool question. I like to keep students thinking about the big ideas like energy.DNA polymerase fixes mutations. Enzymes don't require extra energy to work(though they may be expensive to make). Energy in the form of molecular movement is required, and the more heat, the more movement, the more enzymatic activity. At least until it's so hot that the enzyme is destroyed. So enzymes themselves don't have to be "recharged" to do their jobs, but energy is required for them to work. Here's a good summary of the temperature/enzyme relationship:

energy Of course the big question is, "can anything be done without some form of energy?" By definition, no work can be done without energy. But it's a great idea for students to discuss apparent contradictions as a way of exploring the different forms of energy, energy conversion, and entropy.

Answer 4:

Repairing DNA requires energy. It cannot be done without energy. The Second Law of Thermodynamics states that disorder (entropy) must increase with time, and the restoration of order in DNA therefore requires a greater expenditure of order (releasing energy) elsewhere.

Click Here to return to the search form.

University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2020 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use