nucleic acids Flashcards
test 2
what are the pyrimidine nitrogenous bases
cytosine, thymine and uracil
what are the purine bases
adenine and guanine
what are the common base tautomeric forms
lactam (keto) form
what are the rare base tautomeric forms
lactim (enol)
what does a tautomeric shift mean
spontaneous rearragment of the positoins of protons and electrons within a molecule
what is a nucleoside
nitrogenous base+ sugar
what is the sugar in a nucleoside
D-ribose or 2’-deoxy D ribose
how is the base connected in a nucleoside
Beta- N glycosidic bond on the 1 carbon
what is a nucleoTIDE
nucleoside + phosphate
- phospheric acid is exterified with an OH of the monosacc. mostly on the 3’ or 5’-OH
what is 3’-5’ cylcic adenosine monosphosphate
- derived from ATP
- cAMP is used in signal transduction as an important second messenger
what is this
cyclic adenosone monosphosphate
DNA has deoxy ribose and what bases
AGCT
What bases does ribose have
AGCU
what is the nucleoside for the base Adenine
adenosine
what is the nucleoside for the base cytosine
cytidine
what is the nucleoside for base thymine
doexythimidine = thymidine
what is considered the energy currency of the cell
ATP
many antivirals are what analogs
nucleoside/nucleotide
what is zidovudine
nucleoside analong reverse transciptase inhibtor
zidovudine is a [blank] analog
nucleoside
what is this image of
zidovuine
what is emtricitabine
used for treatment of HIV infection in adults and treat meant
emtricitabine is a [blank] analog
blank
what is this image of
emtricitiabine
what contains minor bases
rna specifically tRNA
what are minor bases in dna
methylated forms of major bases
protect genetic informaiton
name 3 types of xanthines
hyoxanthine
inosine (hypoxanthine + ribose)
xanthine
where is inosine found
in tRNA essenstial for wobble base pairs
how are nucleid acids or polynicleotides joined together
phosphodiester linkages
what is the primary structure or the sequence
read from 5’to 3’ end
how many OHs are in rna
2
how many Hs are in dna
2
what is RNAs problem
stability
why is Dna more stable than RNA
no 2-oH
Rna is susceptible to what
base catalyzed hydrolysis
what are chargaffs rules
G=c. A=T
who explained the base rations
erwin chargaff
what image is this
guanine matiching with cytosine
what image is this
adenine mathcing with thymine
replication is based on what
complementarity
what image is this explaning
the central dogma of molecular biolody
what are some characteristics of B DNA structure
- right handed helix
- perpendicular to the helix
- wide and deep major groove
- narrow and deep minor groove
- phosphate backones
what pitch does B DNA structure have
pitch = 10 bases per turn so 34 angstrons
what is the helix rise per base for B dna structure
3.4 angstrons
is dna antiparallel
yes
what is this image
syn- adenosine and anti adenosine
what structure is this
A-dna
what structure is this
b dna
what structure is this
z dna
helical B is what orientation
right handed
helical Z dna is what hand
left handed
what are telomeres
ends of linear chromosomes
what type of dna does telomere have
tetraplex or quaduplex dna
characteristics of the rna strucutre
- single stranded
- wound back double helical regions that assume type A helix
what enzymes affect dna superstructures
toposisomerases, type 1, type 2
what is topoisomerase
relax supercoils in dna by causing a tansient nick that is sealed
what us Type 1 enzyme
supercoils by breaking only 1 strand ssDNA break
type 2 enzyme
relax or supercoils by breaking both strands dsDNA
what inhibitorsa are widely used anticancer and antibacterial agents
topoisomerase
what are bacterial plasmids
separate small circular moleculs that carry genes
dna packaging in prokaryotes
- circular dna bound to basic proteins to give bacterial chromosomes in the nucleoid
characteristics of dna packing in eukaryptes
- dna packages as chromatin
- coilded around histone octamer
- nucleosomes look like beads on a string
- 1.8 turns
what are the name of the histones
H2A, H2B, H3, and H4
what are histones
small proteins rich in basic amino acids lysine and argine whose side chains have +’ve charge
what charge is dna
-ve
what is number of the last histone
H1
what is alkylation
causes dna mismatch mutations that lead to cancer
what is used for forensic analysis when nuclear dna is too degraded
mitochondiral and chloroplast dna
uv irridation induced dna damage example
thymine dimers (cyclobutyl dimers)
since alkylating agents can cause to cancer what are they called
carinogenic
what is an example of an alkylating agents
mustard gas or nitrogen gas
what is the compound from food that is curred with NaO2 that causes dna mismatch mutations that lead to cancer
HNO2
