Structure of DNA Flashcards
linear polymers of nucleotides that function in the storage and expression of genetic information, and its transfer from one generation to the next
Nucleic Acid
two types of nucleic acids
ribonucleic acid (RNA) De-oxyribonucleic Acid (DNA)
the three molecular components of nucleotides
nitrogenous base
pentose sugar
phosphate
six membered heterocyclic rings of C and N
Pyrimidines
fused six membered and five membered heterocyclic rings of C and N
purines
N-groups can accept protons, giving “basic” properties to the molecule
bases
three characteristics of xanthine and hypoxanthine
rarely occur
are removed during DNA repair
are intermediates in nucleotide catabolism
which bases are found in DNA
adenine
guanine
thymine
cytosine
which bases are found in RNA
adenine
guanine
uracil
cytosine
secondary metabolites of cocoa beans and tea leaves
act as diuretic, cardiac stimulant, and esp vasodilator
theobromine and theophylline
stimulant
diuretic
antagonist to adenosine
caffeine
nitrogenous bases attached to sugars
nucleosides
inhibitory neurotransmitter synthesized in the brain, binds to its respective receptor
adenosine
binding of adenosine causes
drowsiness
dilation of blood vessels
what competes with adenosine receptor to cause opposite effects
caffeine
antibiotic produced from fungus cordyceps militaris
which inhibits the final step of RNA biosynthesis by termination of the ribonucleotide chain
cordycepin (3’ deoxy adenosine)
plant hormones derived from adenine
contains adenine ring system with an attached 5-carbon hydrophobic group at free NH2
promote cell division in plants
cytokinins
when you have the base, phosphate and sugar all together
nucleotide
phosphate acceptor/donor
ATP
protein synthesis and signal transduction
GTP
Membrane and storage lipid synthesis
CTP
carbohydrate synthesis and degradation
UTP
bond between the 5’ carbon and the oxygen of the first phosphate group in ATP
phosphoester bond
bonds between the oxygens of the second and third phosphate groups in ATP
phosphoanhydride bonds
a molecule that ATP is able to borrow phosphate groups from
phosphocreatine
the energy difference before and after a process or reaction occurs
delta G
gibbs free energy
if delta G is +
input of energy required
if delta G -
energy is given off
the reaction is spontaneous
a short lived intracellular chemical signal molecule that relays a message from an external “first messenger” which will lead to a cascade of events
secondary messenger
common first messengers
hormones and neurotransmitters
common secondary messengers
calcium ions
inositol-Pi3
diacylglycerol
cyclic nucleotides
how is cAMP formed
the oxygen on the phosphate group wraps around to bond with the 3’ carbon
involved in many signal cascades including hormone signaling, apoptosis, disease reactions, neuron function
adenylate cyclase (cAMP)
involved in nitric oxide signaling, blood pressure homeostasis, nerve impulse transmission, and stress response in plants
guanylate cyclase (cGMP)
enzyme that produces cyclic amp
adenylate cyclase
explain the cAMP mediated signal transduction
first messengers bind to receptor
activate G protein which changes GDP to GTP
activates active adenylate cyclase
creates cAMP
adenine and thymine form how many hydrogen bonds
2
guanine and cytosine form how many hydrogen bonds
3
DNA and RNA are always read from ____ to ____
5’ to 3’
what is the distance for the major groove
3.3 nm
how many bases are stacked in a major groove
10
each base is how long
0.34 nm
what is the most stable form of DNA
B-DNA
form when DNA/RNA duplexes form and due to low hydration
A-DNA
left handed DNA that can form as a result of torsion during transcription
Z-DNA
helps to compact DNA into cell nucleus
supercoiling
help with the supercoiling process
histones
chromatin is
DNA and histones
8 histones with DNA wound to it
neucleosome
structure of chromatin when neucleosomes are spread out from each other, is easily manipulated, beads on a string model.
euchromatin
neucleosomes and DNA are packed so tightly, no free DNA is available for manipulation
heterochromatin
performed experiments with a harmless and deadly bacteria strains on mice to
Griffith
proved that only DNA transformed strain R, ie, only isolated DNA from strain S could make strain R harmful, not proteins
Avery, MacLeod, and McCarthy
further proved that DNA is the genetic material using viruses
hershey and chase