nucleotide versus base pair

[dayana42200]

Hello everyone

I have a basic question to ask.
What is the difference between nucleotide and base pair?

From what I understand, nucleotide are A, C, G and T.
Base pair is the nucleotide with its complimentary nucleotide, (A-T or vice versa and G-C or vice versa).

If Im doing DNA Sequencing using FASTA,

QUERY Sequence.txt:

>1
AGGTCATT

LIBRARY Sequence.txt:

>Dataset
ACGTGTAT

so the QUERY Sequence.txt contain 8bp or 8 nucleoties?

Also i found some article would write 25kb.
Does kb means kilo bytes or kilo base pair?
If kilo bytes, does this determine by the saved file size?

Thank you very much.

[fznajar]

I use them interchangeably. If you have 8 nucleotides you automatically have 8 bp. Technically, of course, they are different.

[hkeward]

Your understanding is correct - a nucleotide is an individual base, a base pair refers to the base and its complement.
I'm with fznajar; they're used pretty much interchangeably, despite having different meanings. Sometimes the distinction is relevant, often it isn't.

In your example the query sequence is 8 nucelotides (8 bases).

Also i found some article would write 25kb

The article means 25 kilo bases - 25000 bases. Generally speaking, people will talk about DNA in its single-stranded form, particularly when talking about lengths. We know of course that each of the bases has a complementary base, meaning that there are also 25 kilobase pairs, but it's less ambiguous to talk about bases (how many total bases/nucleotides are there in 25 kilobase pairs -- 25000? 50000? two different readers may come to different conclusions).