Respuesta :
ANSWER: The complementary strand will be TACCCGATCAGAA.
WHY:
DNA (Deoxyribonucleic Acid) is made up by different parts called NUCLEOTIDES. In DNA, these nucleotides consist of 3 broad groups:
1. Phosphate Group 2. Five-Carbon Sugar Group (AKA Deoxyribose) 3. Nitrogen Base Group.
The area of focus in this question is group #3: The Nitrogen Base Group, which contains four bases:
1. A- Adenine 2. G- Guanine
3. T- Thymine 4. C- Cytosine.
Adenine and Guanine, or A and G respectively, are an example of a PURINE, which simply means they consist of a 6-Atom Ring & 5-Atom ring that share 2-Atoms. Meanwhile, Cytosine and Thymine are a type of PYRIMIDINE, composed of 1-Atom ring.
Together, these four nitrogen bases are part of the double helix of DNA that are separated into 2 groups of 2 (BASE PAIRS), each consisting of one purine and one pyrimidine. The base pairs are: A-T, and C-G. They can only be paired in this way because their shapes complement one another, allowing them to bond with each other using hydrogen bonds. In the case of A-T, two hydrogen bonds form; while in C-G, three hydrogen bonds form.
Therefore, the answer is TACCCGATCAGAA. If it is difficult to see why, it's best to draw them out like so (the lines in between are optional) and try pairing them out:
A T G G G C T A G T C T T
| | | | | | | | | | | | |
T A C C C G A T C A G A A
In doing so, one can see more clearly if the pairs are correct. Again, the pairs are A-T & C-G. One way to memorize this is to remember that the letters G and C look almost identical (&/or think of CoG, like the gear), whereas for A-T, think "Where are you AT?", or any other mnemonic device that makes sense.
Here are some practice questions:
1. Find the complimentary strand of ATTCGT?
2. Is the following base pair true: CGGATG and GCCGAC?
3. What are the two base pairs?
Answers
1. TAAGCA
2. False A&G is not a pair.
CGG(A)TG
GCC(G)AC
3. A-T and C-G
