2.11 Replication Flashcards
Bonds that join the 3’hydroxyl group of the deoxypentose of one nucleotide to the 5’hydroxyl group of the deoxypentose of an adjacent nucleotide through a phosphate group
Phosphodiester bonds
Single unique nucleotide sequence wherein prokaryotic DNA replication begins
Origin of Replication
Protein that binds to specific nucleotide sequences at the origin of replication, causing short, tandemly arranged AT regions in the origin to melt
DNA-A Protein
Enzyme that binds to ssDNA forces the strands apart, unwinding the double helix
DNA helicases
Proteins that bind to newly separated ssDNA in order to hold them apart.
Single stranded DNA binding proteins (SSBP)
Enzymes that cut one strand of the double helix to relieve supercoiling
DNA Topoisomerase Type 1
Enzymes that make transient breaks in both dsDNA strands
DNA Topoisomerase Type II
Monomeric units or building blocks of nucleic acids
Nucleotides
Functions of nucleotides
Precursors for informational molecules Part of coenzyme Donors of phosphoryl groups Regulatory nucleotides Synthetic analogues as drugs
Nitrogen-containing cyclic compounds whose rings contain both carbon and other elements
Nitrogenous bases
Purine
Guanine
Adenine
Pyrimidine
Cytosine
Uracil
Thymine
Has two rings
Purine
Has one ring
Pyrimidine
Has a planar characteristic that facilitates stacking of rings one on top of each other
Nitrogenous bases
Pair with two H-bonds
Adenine and Thymine/
Adenine and Uracil
Pair with three H-bonds
Guanine and Cytosine
Also known as methyl uracil
Comes from folate system
Thymine
Nitrogenous base + sugar
Nucleoside
Link between nitrogenous base and ribose sugar
beta-N-glycosidic bond
Anomeric carbon is attached to ___ for pyrimidine, and __ for purine
N1; N9
Nucleosides + phosphate
Phosphorylated nucleosides
Nucleotide
Esterified to a hydroxyl group of the sugar
Phosphoryl group
Phosphoryl group usually attached to __ of the pentose
C-5
5’-phosphoryl group forms a ___ with the 3’-OH of another nucleotide
Phosphodiester bond
Catalyze the hydrolysis of phosphodiester bonds
Phosphodiesterases
True or False
DNA is more table than RNA.
True
Presence of hydroxyl group in carbon 2 of RNA makes it suscpetible to base-catalyzed hydrolysis
5’ end
Phosphoryl group
3’ end
Hydroxyl group
Polymer composed of nucleotide building blocks
Chemical basis of heredity
DNA
DNA can be cleaved ___ by chemicals and hydrolyzed enzymatically by ___ or ___
Hyrolytically
Exonucleases
Endonucleases
DNA has ___, meaning the strands run in opposite directions
Antiparallel strands
True or false
DNA, regardless of the number of strands, follows Chargaff’s rules
False
Chargaff’s rule does not apply in single-stranded DNA (ssDNA)
Supercoiling of the DNA is being regulated by ___
Topoisomerases
Name the 3 processes in central dogma
Replication
Transcription
Translation
A process in which DNA makes identical copies of itself, which are transmitted to the daughter cells during cell division
Replication
Occurs during the S (synthesis) phase of the cell cycle
Replication
New complementary strand is synthesized from 2 old single strands
The base sequence of each old strand predicts base sequence of the new complementary strand
Semiconservative
Basis for the accuracy of DNA replication
Complementarity
Enzyme that catalyzes addition of DNA nucleotides to a gw
DNA polymerase