Chpt 4 Nucleic Acids Flashcards
what are the 2 types of nucleic acids?
DNA and RNA
what are the 3 chemical components of all nucleic acids?
- (pentose) sugar
- organic (nitrogenous) base
- phosphate group
why are they called ‘nucleic’ acids?
the guy who discovered them found them in cell nuclei
what’s the main difference between DNA and RNA?
the nature of the sugar component is different
in a nucleic acid, which of the sugar’s carbons is the BASE usually connected to?
prime C1
in a nucleic acid, which of the sugar’s carbons is the PHOSPHATE usually connected to?
prime C5
In DNA and RNA, how are chains of nucleic acids connected to one another?
the phosphate group from one nucleic acid (attached at C5) connects with the other nucleic acid at C3
what are the 2 bases that a nucleic acid can have
purine or pyrimidine
why are the carbons in a nucleic acid’s sugar called ‘prime’ carbons?
to keep them from getting mixed up with the carbons from the base and phosphate
what are the two types of purine bases that a nucleic acid can have?
adenine and guanine
what are the 3 types of pyrimidine bases that a nucleic acid can have?
cytosine, uracil and thymine
uracil is only in RNA
what base can RNA have that DNA can NOT have?
RNA has uracil instead of thymine
what is a (nitrogenous) base, as found in nucleic acids?
an organic molecule that contains the element nitrogen and acts as a base in chemical reactions.
how many classes of (nitrogenous) bases are there?
2 (purine and pyrimidine)
Are (nitrogenous) bases in nucleic acids polar or non-polar?
non-polar
are (nitrogenous) bases planar or 3D?
planar
how many different (nitrogenous) bases are there?
A lot, but we only need to know the 5 that are in DNA and RNA for our class
are (nitrogenous) bases aromatic?
yes
why does Shimko call the (nitrogenous) bases heterogenous?
because they are rings that include atoms other than just carbons and hydrogens.
They have nitrogen
what role does the sugar/pentose play in the structure of a nucleic acid?
it serves as the backbone of the structure
what is ribose?
a cyclic sugar whose :
- ring(?) has 5 carbons, and oxygen, and an aldehyde group
- structure has has 3 OH groups on it
is ribose found in DNA or RNA?
RNA
in order to draw a ‘stereochemically correct’ nucleic acid, where should the (nitrogenous) base be located relative to the 5C carbon?
the base and the 5C carbon must be drawn on the same side of the ring
(on a flat representation, they must both be pointed up or both be pointing down)
what is the difference between a DEOxyribose and a ribose?
ribose has OH groups on its C2 and C3 carbons. Deoxyribose has H on its C2 carbon instead.