Unit 1 Chapter 4: Nucleic Acids Flashcards
What is a nucleic acid
a polymer made up of monomers called nucleotides
What are the 3 components of a nucleotide
5C sugar, nitrogenous base and a phosphate group (phosphate bonded to sugar which is bonded to N-base)
What is a sugar
an org. compound with a carbonyl group and several hydroxyl groups
Which carbon is the phosphate group attached to in the nucleotide
5’
What are the differences between RNA and DNA
- ribose vs. deoxyribose
- OH at 2’ C vs H at 2’C
- single strand vs. double
- hairpin vs. double helix
- uracil vs. thymine
Purines
guanine. adenine
* larger than pyrimidines
Pyrimidines
cytosine, thymine, uracil
How do nucleotides polymerize to form RNA and DNA
by forming phosphodiester linkages through condensation rxns (between the phosphate group of one nucleotide and the hydroxyl group of the sugar of another)
A phosphodiester linkarge joins the ______carbon on the ribose of one nucleotide to the ______carbon on the ribose of another
5’, 3’
The sugar-phosphate backbone of a nucleic acid is
directional (one strand goes 5’ -> 3’ and the other goes 3’ -> 5’)
The sequences of bases found in RNA/DNA are always written in the ____ direction
5’->3’
Where are new bases added
3’ end
The primary structure of a nucleic acid is
the sequence of nitrogenous bases
Are base pairs located in the interior or exterior of the double helix
interior
What does the phosphate group do for nucleotide
make it charged
What do N-bases do
store info
Why do organisms living in high temperatures have more C and G bases
because they have one more H-bond which makes them stronger
Which carbon do N-bases bond to on the 5 C sugar
1st C
What did Rosalind Franklin do
collected the X-ray diffraction pattern of DNA and also helped discover the double helix
What type of bonds form between base pairs
H-bonds
What does the addition of one or more phosphate groups do
raises the pot. energy of substrate molecules enough to make an otherwise endergonic rxn possible
Where does most DNA and RNA synthesis occur
the nucleus
What are the 2 empirical rules of DNA
- # of purines=# of pyrimidines
2. # of A and T are equal and # of C and G are equal
DNA strands are… (direction)
anitparallel
How many H bonds form between each base pairing
- 2 between A and T
- 3 between C and G
What part of DNA is hydrophob/philic/ what is the whole molecule?
inside is phobic, outside is philic, total is hydrophilic
How is DNA stabilized
hydrophobic interactions in the interior and H-bonding between base pairs
What is the secondary structure of DNA
double helix
Who discovered the double helix
watson and crick with help from the findings of rosalind franklin
How is DNA copied (3 steps)
- heat or enzyme rxns cause double helix to separate
- free deoxyribonucleotides form H-bonds with complementary bases on the original DNA making a template strand (direction opposite to og strand)
- complementary base pairing allows each double helix to be copied making 2 daughter molecules
Is DNA or RNA more stable, why
DNA because it doesnt have the OH on its 2’C and its antiparallel strands form a double helix
What are the 2 functions of a self replicating molecule
- carry info
2. perform catalysis
What is the primary structure of RNA
sequence of nucleotides
Which evolved first DNA or RNA
RNA
What is the secondary structure of RNA
- results from base pairing
- hair pin(single strand =loop, double =helix)
How do the secondary structures of RNA and DNA differ
in RNA bases undergo H-bonding with complementary bases on the SAME strand where in DNA they bond with those on a different strand
What is the tertiary structure of RNA
forms that fold distinctive 3D shapes
What is the quaternary structure of RNA
associations between several RNA molecules
What is the intermediate between the complexity of proteins and simplicity of DNA
RNA
Are N-bases more accessible in the major or minor groove of the DNA helix
major
