Why can't adenine and cytosine pairs form?

  • Thread starter joejo
  • Start date
  • Tags
    Form
In summary, DNA replication is important for the survival of organisms because it allows for the creation of new, complex molecules.
  • #1
joejo
150
0
hi I was curious Why can't adenine and cytosine pairs form? Like I know it doesn't happen but WHY?

thanks for your help guys and girls!
 
Physics news on Phys.org
  • #2
joejo said:
hi I was curious Why can't adenine and cytosine pairs form? Like I know it doesn't happen but WHY?
It is not that they can't bond at all. It is just that the total bond strength is not very strong, so it is not stable. All bonds are hydrogen bonds, so to make a strong molecular bond there have to be many points of contact between points with opposite polarity. This will only occur if the shapes are complementary so that they fit together. The fact is that the shape of adenine and the shape of cytosine don't fit together very well. Thymine (or uracil in RNA) fit much better with adenine, providing many more points of hydrogen bonding and a much more stable bond.

AM
 
  • #3
hey andrew,

thanks soo much its makes more sense now...because they are all constant at 2nm but then again there will be a lack of hydrogen bonding making the pair unstable...


my next ? is why is duplication important? is there any reason behind the importance of duplication/replication
 
  • #4
joejo,

"is there any reason behind the importance of duplication/replication"

That depends on what makes something "improtant". Nature doesn't care one way or the other whether one of its processes involves the replication of extermely complex molecules. It just stumbled on to this system, and the result was living organisms (which it also doesn't give a hoot about). However, as living organisms ourselves, we tend to think that life IS important. And without replication there wouldn't be any.
 
  • #5
true true...thanks jdavel...i thought there was something scientific behind its importance...is there?
 
  • #6
joejo said:
my next ? is why is duplication important? is there any reason behind the importance of duplication/replication
Without the ability to duplicate, a successful molecule (ie. successful in surviving in its environment) would not proliferate. Successful molecules that duplicate themselves would proliferate. It is as simple as that.

AM
 
  • #7
thanks guys! now i completely understand the importance of DNA
 

Related to Why can't adenine and cytosine pairs form?

1. Why can't adenine and cytosine pair together?

Adenine and cytosine cannot pair together because their chemical structures and hydrogen bonding capabilities do not allow for a stable pairing. Adenine has a double-ring structure, while cytosine has a single-ring structure. This difference in structure makes it energetically unfavorable for them to form a stable hydrogen bond.

2. Can adenine and cytosine form a base pair in DNA?

No, adenine and cytosine cannot form a base pair in DNA. In the DNA double helix, adenine always pairs with thymine, and cytosine always pairs with guanine. These pairings are based on the complementary base pairing rule, where adenine and thymine form two hydrogen bonds, while cytosine and guanine form three hydrogen bonds.

3. What is the significance of adenine and cytosine not being able to pair together?

The inability of adenine and cytosine to pair together plays a crucial role in maintaining the stability and accuracy of DNA replication. If adenine and cytosine were able to pair together, mutations would occur at a higher rate, potentially leading to genetic disorders or diseases.

4. Can adenine and cytosine pair together in RNA?

No, adenine and cytosine cannot pair together in RNA either. While RNA does not have thymine, it still follows the complementary base pairing rule, where adenine pairs with uracil and cytosine pairs with guanine. This allows for RNA to have a similar structure to DNA and perform its functions effectively.

5. Are there any exceptions where adenine and cytosine can pair together?

In rare cases, adenine and cytosine can form a weak bond known as a wobble base pair. This occurs in certain RNA molecules and plays a role in protein synthesis. However, this pairing is not stable and is only possible due to the flexibility of RNA structure.

Similar threads

  • Introductory Physics Homework Help
2
Replies
44
Views
2K
  • Chemistry
Replies
3
Views
2K
  • Biology and Chemistry Homework Help
Replies
1
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
334
Replies
44
Views
2K
  • Introductory Physics Homework Help
Replies
10
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
303
  • Biology and Chemistry Homework Help
Replies
1
Views
2K
Replies
2
Views
908
  • Quantum Physics
Replies
6
Views
946
Back
Top