Chapter 4 Nucleic Acids and RNA Flashcards
DNA stores ______ and is replicated using ______
genetic information, proteins
RNA world hypothesis
proposition that at one point in evolution RNA store genetic information and catalyzed its own replication
DNA
deoxyribosenucleic acid
RNA
ribonucleic acid
nucleic acids are polymers made up of…
monomers called nucleotides
3 component of a nucleotide
- phosphate group
- five carbon sugar
- nitrogenous base
what are the monomers of RNA?
ribonucleuotides
what are the monomers of DNA?
Add to dictionary
what are the 4 possible nitrogenous bases for DNA?
cytosine, thymine, guanine, adenine
what are the 4 possible nitrogenous bases for RNA?
cytosine, uracil, guanine, adenine
difference between pyrimidines and purines?
purines have two rings from 9 atoms, while pyrimidines have a single ring of 6 atoms
name the 3 pyrimidines
cytosine, uracil, thymine
name the 3 purines
adenine, guanine
explain the different in the sugar group of DNA and RNA an why it is significant
ribose in RNA has a hydroxide group bound to the 2’ on the carbon ring, while deoxyribose in DNA only has a hydrogen bound to the 2’. the OH group is much more reactive, so RNA can catalyze more reaction while DNA remains much more stable
to which points on the carbon sugar do the phosphate groups bind to form the backbone?
the 5’ and 3’
to which point on the carbon sugar do the nitrogenous bases bind?
the 1’
explain the phosphodiester linkage between the 3’ on the sugar group and the phosphate group. what type of reaction occurs?
the O linked to the sugar binds to the P group, releasing OH and H, water, so this is a condensation reaction
direction that sequences of bases are written
5’ to 3’
direction that strands of DNA and RNA are replicated
5’ to 3’
explain where the energy for polymerization comes from
adding 2 phosphates to a nucleotide (creating a nucleotide triphosphate) increases the potential energy. These become activated nucleotides, an example of this is ATP
what is ATP
an activated ribonucleotide called adenine triphosphate, it carries a large amount of potential energy, the energy is released when the phosphates are released so the molecule can form more stable bonds
Chargaffs rule(s)
A DNA molecule has an equal number of pyrimidines as purines, the # of A’s = # T’s, and the # of C’s = # of G’s
Rosalind Frankilind and Maurice Wilkins
X ray crystallography, DNA has a regular structure, it is helical
Watson and Crick
complementary base pairing between A-T and C-G, purine-pyrimidine pairs
number of bond forms between base pairs
3 hydrogen bond between C-G, 2 hydrogen bonds between A-T
antiparallel strand form:
double helix
meaning of antiparallel strands
one runs 5’ to 3’, the other 3’ to 5’
why double stranded structure of DNA is important for replication
both strands of DNA can act as a stable template for synthesis of new DNA
how does hydrogen bonding effect the secondary structure of RNA?
the majority of the purine-pyrimidines bonds form with bases on the same strand, causing the RNA to fold over into a hairpin structure
hairpin structure
RNA which has forms a double helix with an unpaired loop on one end
RNA synthesis
- complementary bases pair
- copied strand polymerizes
- template and copy separate
- copy serves as a template
- new copy polymerizes
- new copy is identical to original template
ribozymes
catalytic RNA, or RNA enzymes as they are capable of forming complex structure to react multiple ways
