lec 2: nucleic acid structure Flashcards
this is an unbranched polymer with monomer units called nucleotides
nucleic acid
are the building blocks of nucleic acids
nucleotides
The first scientist to isolate nucleic acid in 1869
Johannes Friedrich Miescher
the three-subunit molecule is composed of:
- pentose sugar
- phosphate group
- nitrogen-containing heterocyclic base
2 types of nucleic acid
- deoxyribonucleic acid (DNA)
- ribonucleic acid (RNA)
the template/basis for transmission of genetic information
DNA
Protein synthesis and regulation of gene expression
RNA
this sugar is present in DNA
pentose ribose
Sugar + Base
nucleoside
the third component of a nucleotide
phosphate
where is phosphate attached?
to the 5’ carbon
sugar + base + phosphate = ?
nucleotide
a monosaccharide having five carbons
pentose ribose
the sugar unit is either:
- pentose ribose
- 2’ - deoxyribose
this sugar is present in RNA
2’-deoxyribose
bases under purines
adenine, guanine
bases under pyrimidines
cytosine, thymine, uracil
bases present in both DNA and RNA
A G C
the base present in RNA as a substitute for thymine
uracil
this base is only present in DNA
thymine
2 categories of bases
purine, pyrimidine
is purine bigger than pyrimidines?
yes na yes 4 u bec 2 ang closed rings niya
The nucleotides are linked to each other through
sugar-phosphate bonds
does the sugar-phosphate backbone vary?
no
if the sugar-phosphate backbone does not vary, where does the structure of the nucleic acid depend?
on the sequence of bases
primary structure of DNA segment
5’ TGCA 3’
proposed an explanation for the base composition patterns associated with DNA molecules
James Watson & Francis Crick
The bases (side chains) of each backbone ____ _____ toward the bases of the other strand
extend inward
The two strands in DNA are connected by ____ _____ between their bases
hydrogen bonds
are the DNA strands parallel?
no, it’s antititititi-parallel
what can only fit within the DNA helix interior?
1 purine, 1 pyrimidine
pairs of bases in a nucleic acid structure that can hydrogen-bond to each other
complementary bases
pair of A
T (thymine)
pair of C
G (Guanine)
can the strands be identical in DNA?
NONONONO
predict 3’ A-G-T-C-G-T-A-C-A-T-G 5’
5’ T-C-A-G-C-A-T-G-T-A-C 3’
The two strands of the double helix run in ____ directions
opposite
Derivative of pyrimidine and seen in DNA
thymine
What is the difference between ribose and deoxyribose?
second carbon atom
Derivative of purine and seen in RNA
none
what is the RNA nucleoside with uracil as sugar?
uridine
Identify the DNA nucleoside with adenine as sugar
deoxyadenosine
DNA Nucleotide with cytosine as sugar
deoxycytidine 5’-monophosphate
