What are the base-pairing rules for DNA?

Question

1. A-G; T-C
2. A-C; T-G
3. A-U; C-G
4. A-T; C-G

A RNA molecule is typically

1. a double helix
2. single-stranded
3. double-stranded
4. triple-stranded

Answer 1

4. A-T; C-G

A's pair with T's and C's with G's.

Adenine and Guanine are a class of molecule called purines
Cytosine and Thymine are pyrimidines.

A base pair has one purine and one pyrimidine.

In RNA, uracil, which differs from thymine only in that uracil lacks a methyl (CH3-) group present in thymine, replaces thymine.

An RNA molecule is typically
2. single-stranded

Answer 2

For the first question, choice 4 is correct: A-T; C-G (Adenine-Thymine); (Cytosine-Guanine).
....Under normal cellular conditions, hydrogen bonds only form between specific purine and pyrimidine bases. Adenine and guanine are purines, and cytosine and thymine are pyrimidines. In other words, in a DNA double helix, hydrogen bonds form between purines-pyrimidines only. 2 hydrogen bonds form between adenine and thymine, and 3 hydrogen bonds form between cytosine and guanine. Thus, the C-G bond is stronger than the A-T bond, and thus the C-G bond takes more energy to break than A-T.

The base U, or uracil, is not found in DNA. Uracil replaces thymine in RNA.

For the second question, RNA id typically a single-stranded molecule. If you think about DNA transcription, which is semi-conservative, meaning that one strand serves as the template and the other DNA strand serves to ensure a perfect copy of the DNA is retained. Only 1 mRNA is produced from the DNA double helix, as only a single mRNA strand is used to translate protein.

Answer 3

The base pairing rule is 4.. Adenine pairs with thymine, cytosine pairs with guanine..

basicly.. purine pairs with pyrimidine.. so..

purine= Adenine, guanin
pyrimidine= Thymine, cytosine...

Rna is a single stranded with ribise sugar as the pentose sugar..

Answer 4

A(adenine) T(thymine)
G(guanine) C(cytosine)



RNA is single-stranded

Answer 5

A_G
T-C

Option A is correct

In RNA Thymine (T) does not exist

At the start codon A is paired with U instead of G