Answer:
a. AAA TCG
b. CGA AAT
Explanation:
DNA and RNA both have 4 nitrogenous bases, and the base pairing rule dictates which one each will bond with. If you have a hard time visualising the base paring rule, imagine it as two pairs of lovebirds.
So in DNA:
A ♡ T
(likewise) T ♡ A
C ♡ G
(likewise) G ♡ C
A will only bond with T, and C will only bond with G. Likewise, T will only bond with A and G with C. But you might've noticed that in your picture, there are no T! This is because this is a RNA strand instead of a DNA one, so the base paring rule is a bit different.
In RNA:
A ♡ U
(likewise) U ♡ A
C ♡ G
(likewise) G ♡ C
When transcribing RNA strands into DNA ones, the U's always translate to A, and the A's always translate to T's! You can think of the U's as the T's of RNA -- just (mentally) replace all the U's in the picture with T's, and the DNA base pairing rule applies. T's always translate to A, and the A's always translate to T's, right?
Another way you can make solving this question easier is to rearrange the bases vertically so it looks much more like the familiar base pairing rules layout!
U ♡ A
U ♡ A
U ♡ A
A ♡ T (because we're going RNA -> DNA, and DNA doesn't have base U!)
G ♡ C
C ♡ G
UUU AGC -> AAA TCG
In the answer you will see that all 4 DNA bases (A,T,C,G) are present :)
tdlr; if you're going RNA -> DNA, no U's in answer (replace them with T's!). If you're going DNA -> RNA, no T's in answer (replace them with U's!)
In either way both of them love A very much and will always translate into A :)
