When do we use 'a' and 'an'?

[Stephanie]

Dear all, I have a question, is it:
a mRNA

or an mRNA ?

I cannot find the rule anywhere and also my english speaking collegues cannot help!

thanks a lot!

[Pamela]

I don't know what mRNA is - acronym or anything else but you must use an article "a"("a"is used before consonant sounds and "an" before vowel sounds)
Ex.An apple, a peach
Hope,it's clear

[Guest]

thank you very much. what you wrote is clear to me. however, if you pronouce m it starts with a vowl....thats why i asked...for peach it is clear...

[Pamela]

"m" is not a vowel but can you explain what mRNA is.

[Guest]

ok, i found the anwer myself...just replying to you to let you also know....

"an is used before words starting with a vowel sound, regardless of whether the word begins with a vowel letter"
so an mRNA is correct (mRNA stands for messanger RNA wich is a product of the DNA of each of a bodies cell)

greetings,

stephi

[Yankee]

Hi Stephanie

Yes, that's right! With an abbreviation that has a vowel sound at the beginning (even though what you write is a consonant), you need to use "an".

- an mRNA
- an MBA
- an RSVP

Amy

[Pamela]

.I found what I was looking for"The "life cycle" of an mRNA in a eukaryotic cell. The abbreviation itself confused me
Hi Stephanie and Amy!By the "vowel sound or consonant sound" I meant not a letter

[Yankee]

Hi Pamela

Yes, I noiticed that you wrote vowel sound in your first post, but since Stephanie still seemed confused and then mentioned that she had 'found the answer herself', I just wanted to confirm the answer.

Amy

[Pamela]

While I was writing to her you've already passed ahead of me