how many amino acids are there?

Question

it's a true or false question. it says" there are 21 amino acids|"
so it it true or false. & how many amino acids are there?

Answer 1

There are 20 that you use. So, false.

Answer 2

There are 20 common amino acids but I think there are more than that and are not that common. The 20 refer to those that are standardly coded for in DNA. Wikipedia says that two other amino acids are very rarely coded for in proteins. It also says that there are a lot of non-standard amino acids that are found in the body but are not used in proteins such as ornithine and lanthionine. I don't know how many non-standard amino acids there are. Wiki says a vast amount. But 20 standard amino acids, not 21.

Answer 3

That is true, those 20 essential amino acids are the ones used by mammals. But there are more amino acids that we do not use. There are 2 more that were just discovered (search Science Weekly). These other amino acids that we do not use may be used by other organisms and especially bacteria.
Articles to read: (The third article has the structure of the 22nd. amino acid. It is an excellent structure.).

http://researchnews.osu.edu/archive/aminoacd.htm

http://www.genomenewsnetwork.org/articles/05_02/amino_acid.shtml

http://pubs.acs.org/cen/topstory/8021/8021notw1.html

good luck.

Answer 4

Any molecule that contains an amine and a carboxyl functional group is an amino acid.. so theoretically there are infinite amino acids.

But only 20 are commonly used in biology.

Answer 5

There are maybe thousands of possible amino acids, if you count acids synthesized in a lab and amino acids that are theoretically possible, but in nature, there now appears to be 21 amino acids:

Answer 6

For a basic bio class, the answer is false.

Answer 7

yup there are 21