Help with genetics?

Question

1. Know which nitrogen bases pair up and be able to identify the corresponding side of a double helix DNA when given the first side
2.Be able to identify the messenger RNA strand when given one side of the DNA ladder

Answer 1

1. DNA's nitrogen bases pair adenine with thymine (these start with letters that have straight lines, so they go together A-T) and cytosine with guanine (these start with letters that are rounded, so they go together C-G).

If this is one side of the DNA:
C G A A T C

G C T T A G is the matching, opposite side.

2. RNA uses uracil in place of thymine, so just put a U wherever you would have used a T in DNA.

If the DNA says:
C G A A T C

G C U U A G is the mRNA that would match it.

Think AUstralia. Don't know why, but this sticks with my students.

Answer 2

the bases are easy.....
Firstly in DNA there are 4...AGCT (or Adenine, Guanine, Cytosine and Thymine)....I always remember A goes with T (and T with A) and G goes with C (and C with G) or that the striaght letters go togehter and the curved letters go together.

whatever is on one side of the DNA molucule the corresponding or complimentary DNA strand will have those letters which I outlined above so if you have a DNA strand that was

AGGCCCCTTGGA

the corresponding DNA strand (ie the other one) would be
TCCGGGGAACCT Easy huh!

Now RNA...firstly RNA is only 1 strand and has NO THYMINE..instead it has a very similar chemical called URACIL...or U....so the 4 bases in RNA are AGCU

G and C are the same and pair up EXACTLY the same as in DNA, but everywhere you would put a T you put a U instead.
If we had the same DNA code as before
AGGCCCCTTGGA The RNA (or tRNA in this case) code would be
UCCGGGGAACCU.....

Just so you know this messenger RNA goes out to ribosomes in the cell and pases this code to transfer RNA and it would be (for interests sake..and continuing on using the same code as above)
AGGCCCCUUGGA....its back to the original, EXCEPT that U is where the T was as its still RNA and still only has U rather than T (but as I said its very similar chemically to T and codes for the right amino acid).

Hope it helps.