NB CH20 Flashcards
Transcription
DNA is transcribed to RNA
Translation
Uses RNA to build proteins
Where does transcription happen?
In the nucleus
Once mRNA has been transcribed, what modifications are done to it? What does this help with?
Poly-A tail is added to the 3’ end
Addition of a 5’ cap
Help increase the lifespan of mRNA
Nucleotide
Sugar, nitrogenous base, and phosphate group
Nucleoside
Sugar and nitrogenous base
What differentiates ribose and deoxyribose?
Ribose has a hydroxyl on the 2’ carbon while deoxyribose doesn’t
Which base pairs are purines and which are pyramidines?
Purines: adenine and guanine
Pyrimidine: cytosine, uracil, and thymine
What is the difference between a purine and pyrimidine?
Purines have two rings, pyrimidines have one
What’s at the 5’ and 3’ end of a nucleotide?
3’ end: hydroxyl group
5’ end: phosphate group
What are the 5’ and 3’ ends analogous to?
3’ end: C-terminus
5’ end: N-terminus
How many H-bonds between A-T?
2
How many H-bonds between A-U?
2
How many H-bonds between C-G?
3
Chargaff’s rule
A = T
C = G
Name of the bond that connects two nucleotides
Phosphodiester bond
Phosphodiester bond
What atoms are involved?
Polar or nonpolar?
Polar bond between oxygen and phosphorus
What is coupled to provide the energy to join two nucleic acid monomers?
An exergonic reaction involving the hydrolysis of one of the phosphoanhydride bonds
What does the reaction joining two nucleic acid monomers generate?
A pyrophosphate ([P2O7]4-), which splits into two inorganic phosphates
DNA Polymerase I
Removes RNA primers and replaces them with DNA nucleotides
DNA Polymerase III
Synthesizes daughter strands
Helicase
Separates parent DNA strands
Ligase
Connects Okazaki fragments
Primase
Generates RNA primers
